3D printing biomimetic materials and structures for biomedical applications

Abstract

Over millions of years of evolution, nature has created organisms with overwhelming performances due to their unique materials and structures, providing us with valuable inspirations for the development of next-generation biomedical devices. As a promising new technology, 3D printing enables the fabrication of multiscale, multi-material, and multi-functional three-dimensional (3D) biomimetic materials and structures with high precision and great flexibility. The manufacturing challenges of biomedical devices with advanced biomimetic materials and structures for various applications were overcome with the flourishing development of 3D printing technologies. In this paper, the state-of-the-art additive manufacturing of biomimetic materials and structures in the field of biomedical engineering were overviewed. Various kinds of biomedical applications, including implants, lab-on-chip, medicine, microvascular network, and artificial organs and tissues, were respectively discussed. The technical challenges and limitations of biomimetic additive manufacturing in biomedical applications were further investigated, and the potential solutions and intriguing future technological developments of biomimetic 3D printing of biomedical devices were highlighted.

Full text

Bio-Design and Manufacturing (2021) 4:405–428
https://doi.org/10.1007/s42242-020-00117-0
REVIEW
3D printing biomimetic materials and structures for biomedical
applications
Yizhen Zhu1·Dylan Joralmon1·Weitong Shan2·Yiyu Chen3·Jiahui Rong3·Hanyu Zhao3·Siqi Xiao2·
Xiangjia Li1
Received: 26 August 2020 / Accepted: 24 November 2020 / Published online: 3 January 2021
© Zhejiang University Press 2021
Abstract
Over millions of years of evolution, nature has created organisms with overwhelming performances due to their unique mate-
rials and structures, providing us with valuable inspirations for the development of next-generation biomedical devices. As
a promising new technology, 3D printing enables the fabrication of multiscale, multi-material, and multi-functional three-
dimensional (3D) biomimetic materials and structures with high precision and great flexibility. The manufacturing challenges
of biomedical devices with advanced biomimetic materials and structures for various applications were overcome with the
flourishing development of 3D printing technologies. In this paper, the state-of-the-art additive manufacturing of biomimetic
materials and structures in the field of biomedical engineering were overviewed. Various kinds of biomedical applications,
including implants, lab-on-chip, medicine, microvascular network, and artificial organs and tissues, were respectively dis-
cussed. The technical challenges and limitations of biomimetic additive manufacturing in biomedical applications were
further investigated, and the potential solutions and intriguing future technological developments of biomimetic 3D printing
of biomedical devices were highlighted.
Keywords 3D printing ·Bioprinting ·Biomimetic material ·Functional structures ·Biomedical applications
Introduction
Traditional manufacturing methods have been used to fabri-
cate biomedical devices for a long period [1]. However, the
human body is composed of complex structures and material
systems, and the current manufacturing technologies, which
are limited in material selection and fabrication capability,
cannot meet criteria that produce biomedical devices with
complex bioinspired architectures and structures, impeding
the development of biomedical devices in diverse applica-
BXiangjia Li
xiangjia.li@asu.edu
1School for Engineering of Matter, Transport and Energy,
Arizona State University, 501 E. Tyler Mall, Tempe, AZ
85287, USA
2Mork Family Department of Chemical Engineering and
Materials Science, Viterbi School of Engineering, University
of Southern California, 925 Bloom Walk, Los Angeles, CA
90089, USA
3Department of Aerospace and Mechanical Engineering,
Viterbi School of Engineering, University of Southern
California, 854 Downey Way, Los Angeles, CA 90089, USA
tions [1]. A promising rapid prototyping technology, addi-
tive manufacturing (AM), also known as three-dimensional
(3D) printing, has emerged to address these shortcomings
[2,3]. Currently, different types of 3D printing technolo-
gies, such as electron beam melting (EBM), two-photon
polymerization (TPP), stereolithography (SLA), selective
laser melting/sintering (SLM/S), direct ink writing (DIW),
extrusion-based 3D printing (EBP), fused deposition mod-
eling (FDM), laminated Object Manufacturing (LOM), and
laser-induced forward transfer (LIFT), have been developed
to create new opportunities for manipulating and fabricat-
ing multiscale, multi-material and multi-functional structures
with precise control of details [1]. Because of the out-
standing fabrication capabilities, 3D printing processes have
wide applications in different fields, including biomedical
engineering, automobile, aerospace, electronics, civil engi-
neering, sustainable energy, etc. [2,3]. As a form of 3D
printing technology, bioprinting, which fabricate biomedi-
cal parts with cells, tissues, growth factors, biomaterials and
other biological related materials, are also rapidly devel-
oped based on existing 3D printing technologies, such as
SLA, DIW, EBP and Ink jet, could be used in bioprinting.
123

406 Bio-Design and Manufacturing (2021) 4:405–428
Alterations of organism’s morphologies are delicately crafted
over millions of years of evolution and the evolved high-
performance biological materials and structures provide us
with valuable inspiration for the design of next-generation
functional structures and material systems [3–7]. Integra-
tion of 3D printing and biomimicry promotes advancements
in the fabrication of functional material and structures for
future engineering systems, which will further lead to break-
throughs of various applications in the biomedical industry
[8].
Along with the progress made in biomimetic 3D print-
ing technologies, an increasing number of materials, such
as metal, ceramic, polymer, composite, and living cells,
can be manufactured to mimic natural or living matter
with unique structures and properties [8–18]. For example,
conventional metallic and ceramic biomaterials have been
studied and applied to the construction of bioinspired scaf-
fold assisted microenvironments [14]. Besides, biomimetic
polymeric material, such as nanocomposite and hydrogels,
has drawn more attention in the growing field of tissue engi-
neering over the past few years [15,19,20]. Compared with
other materials, biocompatible and biodegradable hydrogels
[21] and polymers [22] were long-established for the creation
of 3D cell culture microenvironment. Hydrogel provides an
aqueous environment to support the transportation of nutri-
ent and cell waste [19], and reveals a lot of advantages such
as structural similarity to the natural extracellular matrix
(ECM), easy handling and processing, adjustable biochemi-
cal and biophysical properties [20,21]. Mammalian sourced
hydrogel can be harvested by using detergent treatment to
remove cells and antigens from tissues [22,23], and nonmam-
malian sourced hydrogel can be derived from marine algae
[24,25] and plants [26,27]. For mammalian sourced hydro-
gel, collagen monomers enable self-assembly to form fibrillar
structures and further to be crosslinked into a viscoelastic gel
when temperature, pH, and ionic strength are close to physi-
ological conditions [28]. Currently, the mammalian hydrogel
is an appealing material for diverse biomimetic microen-
vironment applications, such as substrates for in vitro cell
culture [29], and lab-on-chip systems [30]. As for nonmam-
malian sourced hydrogel, alginate has been massively used
to produce hydrogels via many different crosslinking meth-
ods [31,32]. As a potential material solution of bioinspired
medical devices, alginate hydrogels exhibit a lot of promis-
ing properties. For instance, alginate hydrogels can be used
to print bioinspired microrobots for the releasing of small
molecules and proteins, due to bioactive ligands to cells and
adjustable-rate degradation [33–35]. Besides, lots of stud-
ies have manifested the potential applications of polymers
as biomaterials for the fabrication of biomimetic medical
devices [36–38]. The food and drug administration (FDA)
approved polymers, including polyglycolic acid (PGA) [39],
polylactic acid (PLA) [40], poly(lactic-co-glycolic acid)
(PLGA) [41] and poly(ε-caprolactone) (PCL) [42], etc., were
commonly used in diverse biomedical applications, because
of easy processing, consistency, adequate mechanical prop-
erties, and biodegradability [43,44].
Enigmatic natural creatures, such as animal, plants, and
microorganism, which possess unique structures for gath-
ering nutrients or evading from predators, give engineers
massive potential ideas to mimic the natural interior material
ingredients and exterior geometric structures. For example,
hydroxyapatites, known as one type of bone material, were
employed to fabricate the scaffold with biomimetic bone
structures to achieve the desired mechanical requirement for
bone regeneration [13]. Specific bionic microenvironment
to meet the demands of disparate cells has been devel-
oped, and many novel methods were investigated to realize
specific medical goals based on bioinspired structures and
material system [40,45]. For instance, magnetic 3D printed
micro-fish was used as a bioinspired carrier to transfer drugs
into the target area under the control of the magnetic field
[45]. Bionic material systems and structures have achieved
remarkable functionalities, and this review summarized cur-
rent progress in 3D printing of biomimetic materials and
structures for biomedical applications. Inspired by natural
plants and animals, unique biological structures and mate-
rials were reproduced through 3D printing technologies for
various biomedical applications (refer to Fig. 1). This paper is
mainly carried out in five aspects: (1) 3D printing biomimetic
scaffold-based implants. (2) 3D printing biomimetic lab-on-
chip. (3) 3D printing biomimetic medicine for drug delivery.
(4) 3D printing biomimetic microvascular network. (5) 3D
printing artificial organs and tissues. In each aspect, the
investigation covers the bioinspired design scenario of the
functional devices, the development of novel 3D printing
techniques, the adoption of advanced biomaterials, the con-
struction of distinguished biomimetic structures, and current
achievements in specific applications. In the end, the cur-
rent achievement, existing challenges, and outlook of future
further work in the field of biomimetic AM of biomedical
devices will be discussed.
3D printing of biomimetic scaffold-based
implants
Scaffolds are designed with 3D porous structures to achieve
decent mechanical properties for tissue regrowth [46]. The
porous structures with adjustable hole size and distribu-
tion build up a microenvironment for cell attachment and
nutrition exchanging [47]. With the advancement of tissue
engineering, 3D scaffold-based implants play a vital role
to replace and repair tissues and organs [47]. Researchers
tried to create a biological environment similar to the native
tissue environment by utilizing biomimetic scaffolds and
123

Bio-Design and Manufacturing (2021) 4:405–428 407
Fig. 1 Status of biomimetic 3D printing in the biomedical and tissue
engineering. a3D-printed scaffold with bone material using slurry-
based 3D printing for long bone regeneration (copyright is from [14]).
b3D-printed biomimetic micro-texture using projection-based SLA for
cell culture [43]. c3D-printed bioinspired microneedles with mechan-
ical reinforcement using magnetic field-assisted SLA for drug delivery
(copyright is from [44]). d3D-printed microvascular structures using
SLA [140]; and e3D-printed artificial cornea using DIW-based 3D
printing (copyright is from [167])
materials. The biomimetic scaffolds must imitate the intri-
cate properties and characteristics of the native extracellular
matrix (ECM) [48]. Due to the complicated constitution of
human organs and tissues, the biomimetic scaffold needs to
be designed with corresponding bioinspired structures and
materials for the regeneration of related tissue and organ
[49]. The biomimetic design of material and structures brings
challenges for the fabrication due to limited manufacturing
capability and material selection. A lot of efforts have been
made to develop new design and manufacturing methods of
scaffolds to reproduce natural tissue structures and material
system, aiming to achieve superior inter-connectivity, high
porosity, suitable mechanical performance, and controllable
degradation [50]. Conventional scaffold fabrication methods,
such as freeze casting [51], foam replica [52], particle leach-
ing [53], injection molding [54], and solvent casting [55],
showed the shortcomings of fabricating scaffolds with com-
plex biomimetic structures and materials. 3D printing enables
the fabrication with more control and versatility benefit from
the unique material accumulation principle [3]. The advanced
3D printing not only facilitates the design of scaffolds with
bioinspired structures but also produces novel biomimetic
microarchitectures with better anisotropic properties [56].
Besides, 3D scaffolds can be fabricated with novel materi-
als that better imitate the natural ECM by using specifically
developed printing process [14,56–61]. Recent develop-
ments in biomimetic scaffold fabrication on both fabrication
methods and biomaterials development were reviewed in this
section.
The biomimetic scaffold can be utilized for tissue regener-
ation with the combination of different bioinspired materials
and rapid prototyping techniques. Several novel bioinspired
materials that promote the healing and regeneration of
certain kinds of tissues have been proposed. For exam-
ple, a novel bioinspired nanomaterial consisted of hydro-
thermally treated nano-crystalline hydroxyapatite (nHA) and
core–shell polyacid (PLGA) was developed to mimic a
constructive microenvironment for the regeneration of osteo-
chondral tissue [61]. Due to the biomimetic structure and
composition of nHA, the novel bioink provided mechan-
ical stability for the fabrication of scaffold by using 3D
printing technology (Fig. 2a). Besides, the vivo experiment
result indicated that such bioinspired nanomaterial enhanced
human mesenchymal stem cells proliferation and osteochon-
dral differentiation [57–59]. Another example is that the
hybrid material incorporated chicken eggs (egg white and
eggshell) and gelatin methacryloyl (GelMa) was developed
to fabricate bone scaffold using photopolymerization-based
printing technologies (refer to Fig. 2b) [60]. This new method
extensively kept good biocompatibility and improved the
mechanical properties of newly growing bone tissue based
on the bioinspired material. Thus, bioinspired material-based
scaffolds with, can be fabricated by 3D printing to provide
a desired microenvironment for cell growth with excellent
biological properties.
Moreover, biomimetic structures, which improve the
porosity and mechanical performance, can prompt more
effective cell delivery and tissue regeneration [61]. For exam-
ple, haversian bone structures were reproduced to create
functional scaffold, which demonstrated promising possi-
bilities in multicellular delivery [62]. As shown in Fig. 2b,
haversian canals, volkmann canals and cancellous bone struc-
tures were imitated in the scaffold design by using bioactive
glass and bioceramic for the delivery of cell and nutrition
[62]. The vivo results showed that the scaffold promoted the
ingrowth of blood vessels and new bone regeneration [62].
Lotus root [61] is a common vegetable with unique parallel
channels, and this parallel multichannel architectures con-
nects the lotus root and leaves, achieving air and moisture
exchange with the external environment [61]. This special
architecture is an ideal structure with low density, high poros-
ity, and low flow resistance. Inspired by such microstructure
of lotus root, biomimetic materials were designed and fab-
ricated into the scaffolds with lotus root-like structures for
oxygen perfusion, cell delivery, and tissue ingrowth along
the channels [61]. In addition, lotus root inspired scaffolds,
composed of akermainite (AKT, Ca2MgSi2O7), were printed
to regenerate bone tissue for large bone defects (refer to
123

408 Bio-Design and Manufacturing (2021) 4:405–428
Fig. 2 3D printing of biomimetic scaffolds with novel materials and
structures. aNovel biological inspired nanocomposite composed of
nHA and PLGA was fabricated by 3D bioprinting (copyright is from
[200]). b3D printing of haversian bone-inspired scaffolds for bone
formation (copyright is from [62]). cLotus root inspired bioscaffolds
were printed using biomimetic materials (copyright is from [61]). d3D
printing of the spinal cord structure-inspired scaffold (copyright is from
[65]); and e3D-printed scaffolds with multiscale bone structures for
long bone regeneration (copyright is from [63])
Fig. 2c). The lotus root inspired vascular structure facilitated
the regeneration of bone defects, allowing forth of blood ves-
sels and bone tissues to grow inside the structures [61]. To
fabricate the inner bioinspired microchannel, the unique noz-
zle was modified and the newly developed printing process
provided better flexibility to design scaffolds with complex
bioinspired structures, patterns, and porosity [61]. Kim et al.
[63] developed a novel 3D-printed micropatterned scaffold,
123

Bio-Design and Manufacturing (2021) 4:405–428 409
which mimics microfibril structures for effective muscle cell
regeneration. A PVA leaching process was utilized to obtain
uniaxially aligned polycaprolactone (PCL) microfiber, and
then the aligned PCL fibers were printed to produce aligned
3D structures that mimicked muscle tissues [63]. To func-
tion as a better ECM, PCL fibers were coated with collagen
for the regeneration of muscle fiber [63]. The experiment
results indicated that this bioinspired aligned structure pro-
vided decent mechanical properties and showed potential for
more effective muscle tissue regeneration.
Compared with extrusion-based 3D printing, digital light-
assisted stereolithography (SLA) presents better fabrication
resolution, especially for microscale fabrication. In SLA
printing process, the photocurable polymer is selectively
cured to form the 3D scaffolds with complex structures,
fast speed, and low cost [64]. For example, a microscale
continuous projection-based SLA was applied to fabricate
spinal cord inspired scaffold with central nervous system
structures (refer to Fig. 2d) [65]. Hydrogel made up of
poly(ethylene glycol)diacrylate (PEGDA) and GelMa was
selected as the material of the scaffold, and the neural pro-
genitor cells (NPCs) was loaded into the 3D-printed scaffolds
to support axon regeneration [65]. The vivo test demon-
strated that the biomimetic scaffold with NPCs enhanced the
rebuilding process of central nervous system structures [65].
Besides, hydroxyapatite and tricalcium phosphate (HA/TCP)
are major constituents of natural bone and teeth, and exhibit
attractive biological properties for bone regeneration [13].
HA/TCP scaffolds with certain range of microporous struc-
tures have been successfully fabricated by using different 3D
printing processes; however, it is hard to duplicate the natu-
ral bone structures with hierarchical porosity, which enables
cell growth and nutrient transport [13]. To overcome this
challenge, a microscale slurry mask image projection-based
SLA was developed and a HA/TCP-based scaffold can be
formed with complex geometry including biomimetic fea-
tures and hierarchical porosity [13].
In this section, recent advancements in the fabrication
of biomimetic scaffolds with 3D printing techniques were
present. 3D printing is an effective tool that demonstrates
great potentials in the fabrication of biomimetic scaffolds.
As shown in Fig. 3, 3D-printed scaffolds are developed for
soft tissue and hard tissue regeneration, and physical sup-
porting implant [49]. Combining various bioinspired material
and structures, 3D printed scaffolds demonstrated numerous
advancements in various aspects, such as biocompatibility,
complex geometries, controllable porosities, and mechan-
ical properties. However, there are certain bottlenecks in
biomimetic 3D printing of scaffolds for tissue regeneration.
To be more specific, material selection is subject to the print-
ing principle, and it is still hard to directly process most of
natural material into 3D shapes by using current 3D printing
technologies. A board range of natural material and corre-
sponding manufacturing processes are required to be further
investigated for future bio-fabrication. Moreover, replicat-
ing the original biological structures can potentially simulate
original ECM and produce better support for cell growth and
tissue regeneration. Therefore, more biomimetic structures
should be extensively investigated and explored for scaf-
fold design. The multiscale biomimetic scaffold sets higher
demands on the printing capability of the 3D printing process.
However, current 3D printing processes cannot accurately
reproduce such multiscale natural structure, especially in
micro- and nanoscales, and it still needs further development
for the fabrication of scaffold with multiscale biomimetic
structures for tissue regeneration. Currently, more and more
researches are focused on the invention of multiscale additive
manufacturing technologies, which will bring new possibili-
ties and benefits to the fabrication of biomimetic scaffold for
tissue regeneration [43,66–68]. To sum up, one of the future
trends in scaffold fabrication will focus on developing bioma-
terials and corresponding biomimetic structures that provide
a better biomimetic microenvironment for specific cell regen-
eration and growth. The other direction to further develop
multiscale and multi-material 3D printing processes for the
fabrication of scaffold with distinctive biomimetic structures
and material systems. Besides, bioactive cells and biomate-
rial are used to fabricate the scaffolds for tissue regeneration
by using advanced bioprinting technologies. How to improve
the cell survival rate, cell reaction, and function recovery
of the cell after the printing still is a big challenge that
need to be solved in the future. With developments in both
biomimetic material and structure and the printing process,
advancements of 3D printed biomimetic scaffolds will have
a significant impact on tissue engineering in the long term
and finally become available for clinical applications.
3D printing of biomimetic lab-on-chip
Various methods have been established to work on repro-
ducing the microenvironments of the living organisms in
order to identify the pathological mechanism, study clinical
therapeutic effects, and conduct drug screening for human
wellness [69]. However, due to the limitation of manufac-
turing capability, most of the traditional approaches showed
drawbacks and inadequacy in the representative, validation,
and prediction of real cell or tissue environments [69]. For
instance, recent studies have proven that the animal underly-
ing mechanism is not quite the same as the human beings
[70]; and the 2D cell culture validation method can only
mimic the fragmentary phase of disease rather than the
physiology in tissue or organ level, which may lead to
inaccurate results [71]. The new construction technique of
microenvironment is urgently needed to address these draw-
backs. The development of 3D printing has brought new
123

410 Bio-Design and Manufacturing (2021) 4:405–428
Fig. 3 Summary of 3D printing biomimetic scaffold on resolution,
material and process. a3D printing of degradable scaffold for soft tissue
regeneration (copyright is from [63]). b3D printing of mussel-inspired
scaffold for hard tissue regeneration (copyright is from [201]); and c3D
printing of nondegradable supporting implants (copyright is from [202])
hope to build the bio-mimic microenvironment [43]. Benefit
from the 3D printing technologies, 3D printed biomimetic
scaffold, 3D printed artificial tissue, and 3D printed lab-on-
chip are three main methods that have been widely used
to simulate the actual microenvironment. For example, the
micro-architecture of the 3D scaffold can be precisely rebuilt
by using advanced printing technology so that the printed
scaffolds can mimic the human tissues and create an observ-
able medium for cell culture [72,73]. Artificial tissue and
organ are constructed through precisely controlled deposition
and the combination between material and human cells, pro-
viding a direction of possibility for substitutes of the human
organ [74]. 3D printed tissue and organ enables the drug
screening in vitro without the animal test, increasing the
accuracy and authenticity of the testing results. Besides, it
may achieve in vivo transplantation to ease the problem of
organ shortage for transplantation need [75].
3D-printed lab-on-chip is a technique that integrates sev-
eral microfluidic components and procedures in a single chip
to simulate the chemical and biological processes [76,77].
For example, microvascular networks are fabricated to con-
struct the lab-on-chip [78]. 3D-printed lab-on-chip is widely
used for various purposes including diagnose diseases and
biochemical analysis and detection [78]. The concept of
lab-on-chip is that conduct cell co-cultures in a dynamic
fluid combine with controlled atmospheres contact to achieve
the recreation of important disease models and to under-
stand the physiological mechanisms [79]. In lab-on-chip, not
only biomaterial should be selected and developed, but also
the structure of the living environment for cells should be
reconstructed in order to mimic the microenvironment. For
example, the muscle tissues of the heart forced the heart cells
(cardiomyocytes) to couple mechanical stress to each other,
and further generated elongated cell bundles, which created
an anisotropic syncytium [80]. For achieving the elongation
and coupling of cardiomyocytes, scientists developed unique
structures with groove arrays along the surface. This des-
ignated lab-on-chip with nanostructure provided a suitable
microenvironment for cardiomyocytes to elongate and align
[81]. Another example is that one type of cells, which formed
epithelial tissues of the human liver, is polarized to maintain
efficient mass transfer between three types of surfaces [82].
To realize the function of these cells in vitro, researchers
have demonstrated a method to reproduce the microenvi-
ronment using lab-on-chip for better cell polarization with
modification of the surface of nanofibers [82]. There are still
a great number of undiscovered unique structures in nature,
which can better engineer and reproduce the microenviron-
ment in vitro.
More and more 3D printing techniques, such as FDM,
SLA, DIW, etc. are employed to fabricate the lab-on-chip
for reproducing the biological microenvironment. For exam-
ple, De Jaeghere et al. [83] developed a lab-on-chip with
biomimetic heterocellular-shaped structures to recapitulate
the tumor microenvironment of peritoneal metastases in vitro
and in vivo. Ma et al. [84] adopted a novel bioprinting
approach called a digital light processing (DLP)-based two-
step 3D printing technique to fabricate liver lobule and
vascular structures with photopolymerized gelatin GelMa
and GMHA to encapsulated hiPSC-derived hepatic cells
and the endothelial- and mesenchymal-originated support-
ing cells in complementary patterns (refer to Fig. 4a).
Due to a better morphological organization, higher liver-
specific gene expression levels, larger metabolic product
123

Bio-Design and Manufacturing (2021) 4:405–428 411
Fig. 4 3D printing of biomimetic lab-on-chip for microenvironment
construction. aBiomimetic liver lobule and vascular structures printed
by a SLA-based 3D printing (copyright is from [84]). bA lab-on-chip
with airway combined with a naturally derived blood vessel printed
by a hybrid 3D printing (copyright is from [85]). cAn organ-on-chip
with human skin transwell system fabricated by an extrusion-based
and inkjet-based hybrid 3D printing method (copyright is from [86])
and d3D printing of biomimetic inertial microfluid-based lab-on-chip
(copyright is from [87])
secretion, and enhanced cytochrome P450 induction, 3D-
printed biomimetic models enabled the recapitulation of the
sophisticated liver microenvironment, and can be used in
early personalized drug screening and liver pathophysiology
studies [84].
With the development of tissue engineering, not only a
single fabrication technique or single-material but also multi-
fabrication techniques and multi-material methods were used
to fabricate the lab-on-chip to mimic the microenvironment.
As shown in Fig. 4b, Park et al. [85] utilized a hybrid 3D
printing method, which contained a multi-nozzle and multi-
material system, to fabricate an lab-on-chip that is comprised
of airways with naturally derived blood vessel networks. The
printed vascular platform was assembled with a fully differ-
entiated airway model to reproduce a functional interface
between the airway epithelium and the vascular network
[85]. This model created a microenvironment that enabled
the pathophysiological response to the stimulation in vitro
by mimicking the mucous in the human airway. This bioin-
spired microenvironment can provide a forceful supplement
to test the new drug preclinical drug trial in animal experi-
ments [79]. Kim et al. [86] also developed a hybrid printing
technology, which incorporated extrusion-based and inkjet-
based dispensing modules, to fabricate a lab-on-chip with a
functional skin inspired transwell system (refer to Fig. 4c).
A collagen-based PCL mesh, which can prevent the contrac-
tion of collagen during tissue maturation, was firstly printed
by the extrusion-dispending section. Then, the inkjet-based
123

412 Bio-Design and Manufacturing (2021) 4:405–428
dispensing section was used to distribute the keratinocytes
homogeneously [80]. Benefit from this hybrid printing capa-
bility, long-term human skin-inspired model with functional
transwell systems was obtained, and a feasible microenvi-
ronment can be generated to reproduce the physiological
response of the tissue [80]. Moreover, this hybrid process
opens up perspectives for versatile design and also provides
an attractive method in building various human skin models
[80]. Besides, a chip with inertial microfluidics was fabri-
cated by using SLA-based 3D printing process and multilayer
assembly to monitor the morphological features of the cells
(Fig. 4d) [87].
3D-printed lab-on-chip plays a vital role in maintaining
the biological function of cells and tissues for the microen-
vironment construction [88–90]. 3D printing of lab-on-chip
provides a tremendous opportunity to mimic the microen-
vironment in vitro and in vivo. The printing technologies
and materials used in the fabrication of lab-on-chip for the
microenvironment construction are summarized in Fig. 5.
Various 3D printing methods and bioinspired materials were
adopted to fabricate lab-on-chip to mimic the microenviron-
ment (refer to Fig. 5). Diverse biomaterials, extracellular
matrix, and growth factor, etc., were integrated to pro-
vide essential substances for cell culture, tissue growth, and
drug assays and screening. Manifold unique structures were
designed to mimic the microenvironment for realizing the
normal function of cells. Besides, 3D printing technologies
can be employed individually or integrated with other manu-
facturing methods to produce the biomimetic lab-on-chip. All
these advanced features make it possible to understand the
physiological behavior of tissue/organ and to conduct further
drug screening. The biomimetic well-designed lab-on-chip
enables pathophysiology studies for difficult miscellaneous
diseases. However, it is still a huge challenge to build the
complex lab-on-chip in vivo to complex replace the natural
microenvironment. Hence, more efforts should be made to
compensates these drawbacks. For example, different tech-
niques can be combined to achieve highly simulation of the
in vivo microenvironment by integrating the microfluidic sys-
tems with the newly developed biomimetic 3D matrices into
the design of lab-on-chip [91]. The dynamic detection of the
biomimetic microenvironment, which enables the real-time
monitoring of the cells, tissues, or organs, should be studied
by using advanced lab-on-chip [92]. By considering the time
factor, 4D printing of biomimetic new models and systems
may ultimately persuade further advanced results [93,94].
Based on the printed biomimetic lab-on-chip, massively valu-
able information can be obtained for drug screening, cancer
diagnosis, and pathological analysis through aforementioned
strategies in the future.
3D printing of biomimetic medicine
The quantitative drug delivery, which also can be described
as one-size-for-all treatments, are widely used in medical
treatments [95]. Currently, the mass-produced drug deliv-
ery treatment contained the dose regimens or dosage forms,
which depended on suitable therapy for the majority of the
population. Because of the massive diversity and complexity
of the human body, the drug function is affected by the differ-
ent factors, including but not limited to age, gender, height,
weight, health status, and even human genes, and it may have
limited or excessive effects for different individuals [96].
Consequently, the precision medicines initiative was intro-
duced in 2015 and aimed at the personalization of therapy
[95,97]. The main objective of personal medicines initiative
is to find a suitable platform to carry the therapy to the patient
based on their health status, preferences, needs, and charac-
teristics [96]. 3D printing technologies unlock customization
of personal medicines based on digital design and manufac-
turing [3]. By utilizing the 3D printing technologies, the dose
regimens and the dosage forms can be easily customized
to achieve the precise drug distribution for better therapy
[96]. To control the drug-releasing profile, a wide range of
biodegradable material were developed to produce numerous
geometric shapes of the drug delivery components “printlets”
such as tablets, microneedles, and micro/nanoscale robots,
using 3D printing technologies. The shapes and material of
3D “printlet” are designed according to the natural struc-
tures to efficiently release the drug to the target place in the
human body. With single or multiple drug combination in
3D “printlet”, different types of release mechanism includ-
ing immediate drug release, delayed-release, and sequential
release, can be accomplished [96].
3D printing technologies enable control of the drug-
releasing progress because it can construct the complex
biomimetic structures that can distribute biochemical cues
with a controllable rate in the specific region [98–100].
For example, micro-swimmer, which has a double-helical
biomimetic structure, was printed by the two-photon poly-
merization with biofunctionalized superparamagnetic iron
oxide and GelMa nanoparticles [91]. Due to the magnetic
precursor suspension, the material and the structures of the
micro-swimmer allows itself to travel to the desired regions
by controlling the magnetic field (refer to Fig. 6a) [101]. To
optimize the swimming performance, the shape of micro-
swimmer was designed with biomimetic structures [102].
As shown in Fig. 6b, artificial micro-fish were printed with
PEGDA by using microscale projection-based SLA [102].
Both chemically mediated propulsion and magnetic field
manipulation were used to induce the motion [102]. Poly-
diacetylene nanoparticles as indicators demonstrated the
controllable drug-releasing capability of 3D printed micro-
fish [102]. Motile metal–organic framework can be served
123

Bio-Design and Manufacturing (2021) 4:405–428 413
Fig. 5 Material and 3D printing process of aorgan-on-a-chip (copyright is from [203]) and blab-on-chip for biochemical assays and screening
(copyright is from [204])
Fig. 6 3D printing of biomimetic “printlets” for drug release. aThe
drug delivery mechanism of 3D-printed micro-swimmer (copyright is
from [101]). b3D-printed micro-fish for drug delivery (copyright is
from [102]). cHelical microrobots printed by TPP process (copyright
is from [103]). d3D-printed micro-“printlet” with multi-drugs for target
delivery (copyright is from [108]). e3D-printed medicine with different
drug release mechanisms (copyright is from [110]) and flimpet teeth-
inspired microneedles printed by MF-3DP process for drug delivery
(copyright is from [44])
123

414 Bio-Design and Manufacturing (2021) 4:405–428
as a promising microrobot platform for drug delivery [103].
Magnetic active microrobot with biomimetic helical struc-
tures was fabricated by two-photon polymerization using
biocompatible and pH-responsive hydrogel (refer to Fig. 6c)
[103]. The printed microrobot can swim inside a complex
microfluidic channel network under the control of the mag-
netic field [103].
Recently, many newly developed 3D printing methods
have been examined to apply to the pharmaceutical indus-
try for the clean and precise preparation of tablet-based
medicines. The uniqueness of additive manufacturing can
greatly diversify and prosper the design and manufacturing
process of tablets with regard to its functions and effects.
FDM [104], DIW [105], SLA [106], and inkjet printing [107]
are widely used for dosage form fabrication due to its signif-
icant advantage in material selection and system simplicity.
Dosage is one way widely used in drug delivery, and multi-
stages dosage with different types of drugs that produced by
3D printing technologies provide more flexible and personal
drug treatment. Multi-materials spherical mini “printlet” fab-
ricated by selective laser sintering (SLS) can work as the
carriers for both rapid and sustained release (refer to Fig. 6d)
[108]. SLA shows more flexibility in the design of infill and
the internal void structures due to the material accumulation
principle, where the whole layer of material turns to be solid
upon receiving enough light exposure. For example, tablets
with biomimetic surface modification, such as topographical
modification, protein absorption, mineral deposition, chem-
ical functionalization, were built for regenerative medicine
[109]. Besides, the tablets can be fabricated by the hybrid pro-
cess where the green part of the tablet was firstly produced
by SLA and then active pharmaceutical ingredients (API)
were added by postprocessing such as coating and adsorption
(refer to Fig. 6e) [110]. Another way was to directly print the
tablets composed of active pharmaceutical ingredients (API)
and the cured liquid resin using one process (refer to Fig. 6e)
[110]. The drug release properties of printed tablets can be
modulated by changing the crosslink density and polymer
concentration [110]. For example, the angiogenic factors,
such as growth factors and angiogenic peptides, embedded
in the 3D printed “printlet”, were controllably released into
the damaged area to promote angiogenesis [111,112].
Compared with traditional hypodermic needles,
microneedles devices show a lot of advantages for drug
delivery, such as easy to use, powerful drug delivery, and less
risk infection. Several works have been conducted to design
and fabricate biomimetic microneedles by using microscale
3D printing processes. For example, the mosquito’s pro-
boscis inspired microneedles, which were fabricated by 3D
laser lithography, reduced insertion force due to the sharp-
ness of the 3D printed microneedles [92]. The bioinspired
microneedles had two eaves-trough parts, and they moved
dependently to each other to imitate one hollow microneedle
[108]. The mosquito’s proboscis inspired motion, where the
two halves were inserted alternately in a unique frequency,
dramatically reduced the painfulness and resistive force
during insertion [113]. Bioinspired painless microneedles
(MNs) were fabricated by the magnetic field-assisted 3D
printing (MF-3DP) process [44]. It opens intriguing perspec-
tives for designing MNs with high mechanical strength based
on the limpet teeth inspired hierarchical structures (Fig. 6f)
[44]. The magnetic particles (Fe3O4) were assembled in
the magnetic field to generate the limpet teeth inspired
reinforcement architectures during the printing [44]. The
mechanical reinforcement of MF-3D printed MNs is related
to the magnetic field intensity, the dimension of magnetic
particles and the magnetic particle concentration in the
printable composite [44].
The manufacturing community has benefited from 3D
printing in the past 30 years since 3D printing has the capa-
bility to fabricate complex, customized products with special
design and material distribution [4]. For most of the 3D print-
ing technologies, the product is formed by accumulating
the material in a layered manner, and a lot of 3D print-
ing processes have been developed and utilized to produce
medicines with different material (refer to Fig. 7)[114–119].
Biomimetic structures and the 3D printing process were
refined to accomplish precise and safe drug release. Various
bioinspired architectures were successfully reproduced by
the developed 3D printing process to construct the “printlet”,
and patternable assemblies of drug particles and degradable
material were achieved by using 3D printing for multiple
purpose drug delivery. Besides, 3D printed MNs with bioin-
spired structures show remarkable controllable drug delivery
capabilities and painless treatment [112]. 3D printed MNs
with bioinspired material and structures would be helpful to
further understand the effect of the geometrical morphology
of MNs with bioinspired materials on drug delivery and trans-
portation. Moreover, 3D printed micro/nanoscales robots
with bioinspired material and structures enable efficient drug
delivery, and the advanced AM process opens intriguing per-
spectives for designing micro/nanoscales robots on a basis
of bioinspired features.
Compared with traditional manufacturing processes, 3D
printing improves the safety, efficiency, complexity, toler-
ability of pharmaceutical manufacturing. However, current
3D printed biomimetic objects are most tested in vitro and
in vivo of animals [74]. As for the human body, the bio-
environments are affected by numerous factors, such as age,
gender, weight, height, living environment, and health status.
Every factor would affect the efficiency of drug release and
tissue regeneration [114]. Even though some of the experi-
ments in the animals produced satisfying proofs, the clinic
trial of human still needs to be studied, and the optimiza-
tion and remodeling of 3D printed medicine are required
based on the patients’ conditions in the future. Moreover,
123

Bio-Design and Manufacturing (2021) 4:405–428 415
Fig. 7 3D printing of biomimetic regenerative medicine for drug delivery. Material and 3D printing process and resolution of adrug tablets
(copyright is from [205]). bBioinspired microneedle array (copyright is from [206]) and cartificial micro-fish (copyright is from [102])
although FDA agency encourages the development of cus-
tomized medicine by using 3D printing technology, only few
of 3D printed medicine has been promoted in the market
so far. This is because research experiences of 3D printed
medicine products like tablets, MNs, and micro/nanoscales
robots are limited, and the physical and chemical understand-
ing of drug release from 3D printed products still requires
exploration. Furthermore, the reproducibility of 3D printed
medicine and quality control of mass productions should be
improved in the future. Overall, 3D printing technologies
provide us more possibilities in the fabrication of customized
medicine for pharmaceutical use, and material, design, and
process still need to be further studied and improved in the
future.
3D printing of biomimetic microvascular
network
Microvascular networks, which enable nutrients distribu-
tion, fluid flow, temperature regulation, tissue reparation, and
energy transportation, are crucial transportation systems in
the living creatures [120]. For example, xylem has an amaz-
ing water-conducting system which is contributed to the
lignification of its unique vascular structures [121]. Ligni-
fication is one of the vital phenomena, which can thicken
and harden the vessels in xylem after long-term evolu-
tion. Accompanied by different thickening patterns, such
as helices, coils, or scalariform, the natural architectures
reveals considerable advances in mechanical design that can
be applied in artificial microvascular development for spe-
cific demand [122–124]. Similarly, microvascular systems
of human show many unique functions that benefit from
the shape complexity and material composition. For exam-
ple, blood capillaries in the human body are divided into
three kinds: continuous capillaries, fenestrated capillary, and
sinusoid [125]. Different cells, pipe thickness, and structural
configuration of microvascular leads to different interchange
speeds of material, filtration capacity and ability to store
blood [125].
Biomimetic microvascular structures shows considerable
advances in tissue engineering [126], self-healing technology
[120,127,128], lab-on-chip [75–78], and organ reconstruc-
tion [129–131]. For instance, one or more self-healing agents
can be transported to the damaged area via an artificial
microvascular system to realize the function of repairing or
self-healing [132]. Microvascular networks build the basic
transportation system for multiple applications of lab-on-
chip [75]. Artificial organs possess the biomimetic microvas-
cular transportation system to metabolize and exchange sub-
stances [132]. However, traditional manufacturing methods
impediment the applications of the artificial microvascular
network since it is challenging to reproduce the hierarchical
structures of the natural microvascular network by using tra-
ditional manufacturing technologies [2,132]. To solve this
major bottleneck, 3D printing-based fabrication strategies
have been put forward to build the biomimetic microvascular
network. For example, 3D printing processes such as DIW,
SLA, inkjet printing, and selective laser sintering (SLS), etc.,
are widely used in microvascular fabrication and the smallest
diameter of microchannels that can be achieved by current
3D printing technologies ranges from 1 mm to 20 μm[2,129,
133–135]. Moreover, compared with traditional manufactur-
ing, 3D printing showed advantages in both the complex
design and large material selections. A multitude of sophisti-
cated biomaterial can be processed by 3D printing, enabling
the efficient construction of a biomimetic microvascular net-
work for different purposes [131].
123

416 Bio-Design and Manufacturing (2021) 4:405–428
Fig. 8 3D printing of biomimetic microvascular. aSchematics of
omnidirectional printing of microvascular networks within a hydrogel
(copyright is from [136]). bTriple-coaxial cell printing of vascular
grafts using multi-material bioink (copyright is from [139]). cThe
design diagram and 3D-printed artificial lung network (copyright is
from [140]) and dTrachea and vascular-printed using mask image
projection-based SLA with silk fibroin and glycidyl methacrylate (copy-
right is from [141])
In recent research works, newly developed 3D printing
technologies provide a tool to reproduce the microvascu-
lar system by mimicking the natural architectures [2]. These
printing approaches and research experiences enhanced the
capability of 3D printing to realize more unique functions in
building artificial microvascular. For example, 3D printing
technology, named as omnidirectional Printing (ODP), was
created to simplify the fabrication of microvascular systems
by creatively applying two materials with different chem-
ical and rheological properties [136]. In this process, the
fugitive ink was printed in a photocurable hydrogel reser-
voir, which was infused with calcium chloride and thrombin
(refer to Fig. 8a). After removing the material inside the
channel, large-scale microvascular network was printed with
complex inner structures [136]. The ODP method enables
microvascular fabrication without supporting structures, high
surface quality, and multiscale features [126]. Another sim-
ilar supportless printing approach was developed based on
the hydrogels, which were transferred from solid to the liq-
uid along with temperature change in the reservoir [137].
Different types of material including silicones, hydrogels,
colloids, and living cells were fabricated into vascular struc-
tures by using this approach [137]. Besides, naturally derived
polysaccharide can be used as template material for the
fabrication of microchannel networks [138]. The proposed
vascularized hydrogel demonstrated the capability to support
cellular viability and differentiation [138].
As shown in Fig. 8b, DIW based triple-coaxial cell print-
ing was developed to fabricate biomimetic blood vessels,
which is comprised of both smooth muscle and endothelium
[139]. Specifically, the human umbilical vein endothelial cell,
3% (w/v) vascular-tissue-derived extracellular matrix, and
2% (w/v) alginate facilitated the formation and maturation of
endothelialized vessels [139]. The dense muscularized ves-
sels was created by the human aortic smooth muscle cell,
3% (w/v) vascular-tissue-derived extracellular matrix, and
0.5% (w/v) alginate [139]. The hollow tube structures can be
formed directly with the extrusion of two kinds of material
and the printed bioinspired blood vessels provide a promis-
ing concept to rebuild small-diameter blood vessel grafts for
the treatment of cardiovascular diseases in the future [139].
For vasculogenesis and cell culture, biomimetic aortic vas-
cular was firstly fabricated by 3D bioprinting and the spatial
accuracy was greatly guaranteed by using the medical image
from computer tomography and magnetic resonance imag-
ing [140]. By planting guidance cues for vasculogenesis in
123

Bio-Design and Manufacturing (2021) 4:405–428 417
a hyaluronic acid-based biomimetic hydrogel, microvascu-
lar can be generated with inside self-supporting cells [140].
Furthermore, projection-based SLA facilitated the bioprint-
ing of vessel to fully mimic the biophysical and biochemical
entanglement for different biomedical applications [141]. For
example, the vessel with efficient intravascular mixer and
bicuspid valves were fabricated within a few minutes by
using continuous printing method (refer to Fig. 8c) [140].
Such a printing approach can be used to build artificial organs
for various studies in the future [140]. Further studies of
3D printed microvascular networks regarding space-filling
mathematical topologies of biological entanglement and the
flow of blood in the human body have shown potential inter-
est in the tissue repairing [140]. As shown in Fig. 8d, silk
fibroin and glycidyl methacrylate-based photocurable bioink
was developed to fabricate the vascular with complex struc-
tures [141]. The physical and mechanical property of printed
vascular can be modulated by adjusting the concentration of
glycidyl methacrylate in the bioink [141].
Many progress related to new bioprinting technologies,
bionic design optimization, and functional bioink has been
made for their tremendous advances to obtain microvascular
systems with sound structural integrity (Fig. 9)[142]. Bio-
printing processes, including embedded writing [127,128],
sacrificial printing [138], hollow tube extrusion [139], and
direct printing [141], were developed to build the bioinspired
vascular structures. Meanwhile, layerless bioprinting meth-
ods were investigated to improve the surface quality and
printing efficiency of vascular structures [143–145]. The geo-
metric morphology and material constituent of microvascular
networks are crucial for the transportation systems in terms of
the material interchange and debris filter. The geometries and
material ingredients of artificial vessels were designed and
optimized based on the natural structures (Fig. 9)[146]. How-
ever, it is still challenging to mimic the biological vessel with
full functionality. For example, the printed bionic vessels
can only achieve certain ranges of scales, and the detail fea-
tures of natural vascular networks are hard to be reproduced.
Therefore, multiscale bioprinting process requires farther
exploitation and development for building the microvascular
with all structural elements. Besides, even the appearance
of vessels can be recreated by most of the current bioprint-
ing process, the biological functions of bionic vessels are
limited with respect to cell interaction and propagation, mat-
ter exchange, and filter [147]. Moreover, the most common
materials for printing microvascular are hydrogels with algi-
nate, agarose, gelatin, agar, hyaluronic acid, fibrin, collagen,
silk, and chitosan [129,148–150], and more biomaterials are
needed to developed to satisfy the requires of different cell
living environments for functions such as penetration, and
pinocytosis [129,148,151]. For future work, the involve-
ment of smart manufacturing might bring a breakthrough in
microvascular fabrication. Imaging technology with a finite
element method can provide vessel models with higher res-
olution and mechanical performance. With the development
of biomimetic material, novel design, and advanced printing
technologies, the gap between the artificial vessel and the
natural vessel can be shrunk. Overall, bioprinting of artifi-
cial microvascular might bring new opportunities in the field
of biological and medical engineering with its great potential
for the treatment of various vascular diseases.
3D printing of artificial organs
A large quantity of replaceable artificial organs is required
to achieve better immunological matching between donor
and recipient after an organ transplant surgery [152]. Nowa-
days, artificial organs play a vital role in many aspects,
providing a potential way to produce biological substitutes
of native human tissues or organs for the multiplicity of
applications, such as tissue generation, organ transplanta-
tion, and drug screening, in the biomedical engineering [75].
The production of artificial organs and tissues decreases
the use of animals and increases the reliability of testing
results [75]. Artificial organs and tissues alleviate the short-
age of organ donation for the organ transplantation issue.
Plentiful approaches have been used to develop palliative
methods for the construction of artificial organs and tissues
[153]. However, both morphologies and material systems
of human tissues and organs are sophisticated, most of cur-
rent manufacturing methods could only has ability to mimic
the fragmentary phase of the disease, and there are a lot of
obstacles to accomplish natural tissue activities in the liv-
ing organism [69]. For example, recent studies revealed that
the 2D cell culture chip, which differentiated cell functions,
is hard to mimic tissue or organ-level physiology, and it
may generate biased results [154]. Moreover, even though
a few types of tissues can be mimicked by certain methods,
they were poorly suited to high-throughput validation, due to
high cost, multiple complicated fabrication operations, and
laborious trials [155]. Currently, 3D printing technologies
were involved in the building of complex and variable 3D
organs and tissues, and open intriguing perspective for on-
demand production of implantable biological organs [156].
3D printing affords more benefits in maintaining fabrica-
tion viability and promoting functional maturation. It has
the capability to achieve high-order assembly of arbitrarily
3D artificial tissues and organs with multiple types of bio-
compatible materials and living cells using digital design and
manufacturing technologies [156,157].
Lots of exploration and attempts have been made to
recreate artificial tissues and organs, such as skin, muscle,
heart, and liver, using advanced bioprinting, and the arti-
ficial tissues and organs can be used for drug screening,
toxicity testing, disease modeling, and organ transplanta-
123

418 Bio-Design and Manufacturing (2021) 4:405–428
Fig. 9 3D printing of biomimetic microvascular using different mate-
rial and printing process. Examples of aartificial lung network printed
by SLA process (copyright is from [140]), bmicrovascular networks
printed by DIW process (copyright is from [136]) and ccellular struc-
tures printed by inkjet-based printing process (copyright is from [207])
tion [156,157]. The 3D printed artificial tissues make it
possible to build platforms for drug discovery, chemical anal-
ysis, biological assays, and toxicological testing [157]. For
instance, airflow-assisted 3D bioprinting is a novel method to
build mini tissues on spiral-based microspheres with excel-
lent resolution and sophisticated microarchitectures (refer to
Fig. 10a) [158]. The spheroids were geometrically multiple-
scalar and cell-orientational, and the spiral-based spheroids
were convenient for building functional organoids in vitro
by embedding multiple cells into the spheroid, providing
novel biomimetic asymmetrical prototypes for basic med-
ical research and regenerative medicine [158]. Besides,
heterogeneous spheroids reveal advantages such as multi-
components, controllable morphology, and ease of use [159,
160].
The skin is the organ of human with largest area and
contains both dermal and epidermal layers, which can pro-
tect humans from mechanical damages, micro-organisms,
radiation, and chemicals [161]. Currently, scientists strive
to create skin substitutes for wound treatment by mimick-
ing human skin [162–164]. For instance, fused filament
fabrication (FFF)-based 3D bioprinting technique was used
to fabricate a human plasma-derived bilayered skin using
human fibroblasts and keratinocytes, which were obtained
from skin biopsies [165]. The printed human skin was useful
for the treatment of diverse cutaneous pathologies, such as
burns, ulcers and surgical wounds [162–165]. As shown in
Fig. 10b, a self-contained soft and robust composite mate-
rial was used to produce an actuator to mimic natural muscle
behavior [166]. The phase-changeable ethanol was encap-
sulated in PDMS-based silicone elastomer to achieve high
strain (up to more than 900%) and stress (up to 1.3 MPa) with
low density (0.84 g/cm−3) and costs [166]. This newly devel-
oped material solution could be applied in a variety of areas,
from traditional robotics to advanced biomedical needs, and
may enable a new kind of entirely soft robot [152].
Recently, the pneumatic extrusion bioprinting process was
developed to build artificial corneal, and keratocyte-laden
corneal stromal equivalents were printed with low viscosity
collagen-based bio-inks (refer to Fig. 10c) [167]. Besides,
soft materials with a tensile modulus of 0.8–1.5 MPa were
used to build artificial tissues of the human kidney [168].
This agarose gel outperformed other materials in terms of
the density, elasticity, electrical and acoustic impedances, and
the water concentration of this biomaterial can be tuned to
mimic the corresponding properties of human tissues [168].
Artificial cardiac patch and hearts were also successfully
fabricated by using fully personalized and unsupplemented
bioink, which was prepared the extraction from the patients.
Thus, these 3D printed patches did not provoke an immune
response after transplantation, eliminating the need for long-
term immunosuppression treatment [169,170]. For example,
cellularized artificial hearts with parenchymal cardiac tis-
sue and blood vessel architectures were printed by using
extrusion-based 3D printing (refer to Fig. 10d) [169]. The
cardiomyocytes and endothelial cells differentiated from the
patients’ pluripotent stem cells were mixed with hydrogel
to print cardiac tissue and blood vessels respectively [169].
The immunological, cellular, biochemical, and anatomi-
cal properties of 3D printed perusable cardiac patches can
123

Bio-Design and Manufacturing (2021) 4:405–428 419
Fig. 10 3D printing of biomimetic artificial organs. a3D printing of
spiral-based cell-laden spheroids (copyright is from [158]). b3D print-
ing of soft artificial muscle (copyright is from [166]). c3D printing of
artificial corneal (copyright is from [167]). d3D printing of artificial
heart in support bath (copyright is from [169]). eElectrical field-assisted
3D printing of artificial meniscus (copyright is from [171]) and f3D
printing of artificial ear by using digital NIR based SLA (copyright is
from [172])
achieve the normal index requirements of patients [169]. As
shown in Fig. 10e, the artificial meniscus with the claws of
Homarus americanus inspired bouligand type architectures
were printed by electrical field-assisted nanocomposite 3D
printing [171]. The human meniscus with aligned fibers was
successfully reproduced by orienting the multiwall carbon
nanotubes (MWCNT) in radial and circumferential direc-
tions under the electrical field [171]. The printed artificial
meniscus demonstrated excellent mechanical performance
with the reinforcement of aligned MWCNTs in the poly-
mer matrix [171]. Since the near-infrared (NIR) light is able
to penetrate the tissue, the artificial tissue or organs can be
constructed in the living body without surgery implanta-
tion by using a digital NIR based SLA (refer to Fig. 10f)
[172]. Special biocompatible NIR sensitive nanoinitiators
were developed to induce the photopolymerization in situ
so that this newly developed process avoided the cells injury
during the photopolymerization activated by UV light [172].
What’s more, artificial organs and tissues with compli-
cated inner cavities can be precisely rebuilt using newly
developed 3D printing processes [173]. For example, the
artificial urethra was fabricated with PCL/PLCL (50:50)
polymers by using 3D bioprinting technology [174]. 3D-
printed urethra, which was spatially arranged urothelial cells
123

420 Bio-Design and Manufacturing (2021) 4:405–428
(UCs) and smooth muscle cells (SMCs), was developed to
mimic mechanical property and cell growth environments of
the native urethra [174]. Besides, the liver as one of the most
important organs supports daily detoxification and digestion,
and it has the ability to clean the body of virulence factors
that are caused by venomous injuries, bacterial infections,
and biological weaponry [175,176]. Honeycomb shaped
3D structures containing fibroblast and hepatoma cells were
fabricated by using the extrusion-based printing process to
study the biological characteristics of the artificial liver [177].
Inspired by liver microstructures, the artificial liver-mimetic
tissue, which is consisted of decellularized liver scaffolds
(DLS) and polydiacetylene (PDA) nanoparticles, was fabri-
cated by 3D bioprinting, facilitating hepatocytes to efficiently
detoxify against toxins in the bloodstream [178]. This 3D
printed artificial liver tissue efficiently and target-oriented
removed pore-forming toxins (PFTs) without changing blood
components and complement factors [178]. This approach
provides a new strategy to functionalize decellularized arti-
ficial organs and tissues for medical applications [178].
3D bioprinting has been used to deposit layers of bio-
inks composed of biocompatible polymer matrix and living
cells to build complex artificial tissues and organs in recent
years [173]. Currently, 3D bioprinting has already demon-
strated certain progress in the reproduction of simple tissues
and organs, such as skin [162–165], corneal [167], and ear
[172]. 3D-printed artificial tissues and organs are alterna-
tives for transplantation or regeneration of tissues and organs
[173]. However, there are several challenges to reproduce
the organs, which are composed of multi-material systems,
hierarchical structures and multiple types of cells, using cur-
rent bioprinting approach, then 3D-printed complex artificial
organs, such as kidneys, livers, and hearts, still cannot act
as transplantable organs with fully functionalities at this
moment [179]. As shown in Fig. 11, three types of building
strategies, including SLA, DIW, and Inkjet-based bioprint-
ing, were widely used in the fabrication of artificial tissue and
organs. DIW and inkjet-based bioprinting processes reflect
superiorities in the multi-material fabrication. However, they
getting difficulties in depositing bio-ink with high viscosity
[180–184], and shear stress caused by the extrusion of bio-
ink from the nozzle forces cell deformation [185]. SLA based
bioprinting exhibits advantages in the fabrication of artifi-
cial organs and tissues with sophisticated structures and high
resolution. Meanwhile, there are some shortcomings, such
as multi-material fabrication, high cell viability and densi-
ties, and limited material selections [186–188]. Overall, all
aforementioned challenges of the bioprinting technologies
are necessary to be solved for the mass production of artifi-
cial organs and tissues, and the printable materials anticipated
to mimic the material ingredient of target tissues and organs
will be developed [189–193]. Even though the impressive
progress of bio-ink development has been made for the fab-
rication of artificial tissues and organs, considerable research
topics, such as cell and material compatibility, tissue matu-
ration and functionality, and appropriate vascularization and
innervation, are needed to be further explored in the future
[192,193].
Summary and outlook
Natural structures and material systems give us unlimited
inspiration regarding the novel design of biomedical devices.
The combination of advanced manufacturing and biomimetic
design of structures and material systems initiates the new
generation of biomedical devices for healthcare. Researchers
and scientists have extensively developed various advanced
additive manufacturing technologies to produce biomedical
functional devices with biomimetic structures and bionic
material systems [194–196]. Biomimetic 3D printing as a
promising new technique solved some the manufacturing
challenges of biomedical devices with biomimetic structures
and materials. The development of biomimetic 3D printing
techniques provides an potential tool to develop biomedi-
cal devices with unprecedented functionalities [197]. In this
review, we summarized the recent progress of biomimetic
3D printing of biomedical applications including scaffolds,
lab-on-chip, medicine for drug delivery, microvascular net-
work, and artificial organs and tissue (refer to Fig. 12). The
blossomly development of 3D printing technology makes the
fabrication of biomimetic structures with high complexity
and multiple materials distribution possible. Current progress
in biomimetic 3D printing of biomedical devices reveals the
biomimetic design with various biomaterial and biomimetic
structures bring new advancement for the treatment of health-
care issues in the field of biomedical engineering.
Although significant progress in biomimetic 3D printing
of biomedical applications has been accomplished, there are
still many problems waiting to be solved for the commercial-
ization. Currently, the selection of 3D printing technology is
limited because materials have to be developed according to
the printing principle of 3D printing techniques to treat cer-
tain diseases or defects. And different 3D printing techniques
also have their limitations in printing scale, speed and resolu-
tion. Due to these current challenges, biomimetic 3D printing
technologies only can be used to limited applications. Thus,
more 3D printing process should further be developed so
that the engineers can be given a much wide choice of mate-
rials and 3D printing techniques for biomedical applications.
In addition, more and more researches have been focused
on natural materials investigation. Novel biomaterial is a
fundamental element supporting the construction of natu-
ral extracellular matrix, and enriched library of biomaterials
will raise more possibilities for future biomimetic biomedi-
cal applications. Excellent performances of natural structures
123

Bio-Design and Manufacturing (2021) 4:405–428 421
Fig. 11 3D printing of biomimetic artificial organs using different mate-
rial and printing processes. Examples of aartificial liver lobule and
vascular structures printed by SLA (copyright is from [84]). bArtifi-
cial human skin (copyright is from [86]) and bionic ear (copyright is
from [208])printedbyDIW;andcartificial corneal (copyright is from
[167]) and small-scaled human heart (copyright is from [169]) printed
by inkjet-based printing
Fig. 12 A framework for biomimetic 3D printing of biomedical appli-
cations. aNatural structures lotus root (copyright is from [61]); the
gecko’s foot, inset—enhanced image of a gecko foot (copyright is from
[209]); and bacterium called Escherichia coli or E. coli (copyright is
from [210]). bThe library of 3D printing technologies and material
and material systems are attributed to unique hierarchical
architectures. Even though existing 3D printing techniques
showed capabilities of constructing complex structures, it
is still a particular challenge for the current 3D printing
technologies to accurately duplicate the natural architec-
tures with multiscale structures, especially for microscale
and nanoscale features. Besides, a tradeoff between the fab-
rication resolution and time efficiency exists for most of
123

422 Bio-Design and Manufacturing (2021) 4:405–428
current 3D printing technologies and restrict the production
of biomedical devices by using commercial biomimetic 3D
printing technologies. Thus, the development of 3D print-
ing still needs to find a breaking point in order to provide
opportunities for biomimetic medical devices with high res-
olution and printing speed. Meanwhile, how to achieve mass
production of patient-specific medical devices, or even mass
customization using 3D printing technology is also an issue
for the current biomimetic 3D printing of biomedical appli-
cations, which is one of reasons causing the slow speed of
commercialization of biomimetic 3D printing technologies.
It is essential to invent time-dependent 3D printing systems,
which enable real-time monitor the growth, differentiation,
and maturation of the 3D printed cell, tissue, and organ.
3D printing still needs to be further improved to fabricate
biomimetic structures with better performance. One promis-
ing direction is to develop ultra-fast 3D printing technology
by accomplishing volumetric printing instead of traditional
layer-based printing. For example, volumetric 3D printing
is an approach to solidify resin into the 3D shape within
one-step, which increases the printing efficiency dramati-
cally [198,199]. Another potential direction is to develop
multiscale and multi-material bioprinting approaches since
almost all the natural structures are multiscale and multi-
material. One promising approach is to combine several
different printing processes, which can distributed fabricate
different sections with the specific requirement of scales [66].
Moreover, the 4D printing process, which is a novel 3D print-
ing process integrated with transformation over time, could
also be a future fabrication tool for biomedical applications.
Besides, 3D printing as computer-aided manufacturing will
also benefit from the flourish of artificial intelligence (AI)
and machine learning (ML). Smart manufacturing by inte-
grating biomimetic 3D printing technologies with AI/ML
approaches has a broad prospect in biomedical applications.
AI/ML assisted biomimetic 3D printing technologies open
opportunities for the fabrication of customized biomedical
devices with better quality control, higher processing effi-
ciency, less material waste, and better replacement, etc. The
next revolution in the manufacturing of biomedical devices
will be brought by novel smart 3D printing systems. Contin-
uous study of multidisciplinary research, which integrates
materials processing, computer modeling, medical imag-
ing, chemistry, and biology, will promote the development
of biomimetic 3D printing of biomedical applications for
healthcare [193]. Last but not least, combining 3D printing
with traditional manufacturing methods or other novel fabri-
cation ways, such as robotic technology and laser machining
is also a prospective direction of biomimetic 3D printing
technologies for biomedical applications.
Advancement in biomimetic 3D printing research can
be accelerated by identifying needs, challenges, and oppor-
tunities in biomedical industry, such as biopharmaceutical
treatments, medical implant, etc. In the future, biomimetic 3D
printing technology with sustainable development features
will gradually take the dominant position in the fabrica-
tion of medical devices for the industry community. More
advanced bioinspired materials and structures combined with
advanced 3D printing will provide unprecedented possibil-
ities for researchers to solve the challenges in biomedical
engineering. Future study of biomimetic 3D printing will not
only enable the extension of current researches in biomedical
applications such as implantable scaffold, target drug deliv-
ery, and transplantable artificial organs, etc., but also generate
more functions and applications than ever before. Based on
the blossomly development in the biomimetic 3D printing,
it is not hard to prospect that the more and more 3D-printed
biomimetic medical devices are going to gain a foothold in
the market to help doctors to solve various medical conditions
[190]. The growth of biomimetic 3D printing research will
construct a new biomedical industrial ecosystem for further
facilitating the development of manufacturing and activating
more innovations of biomedical devices for healthcare in the
future.
Acknowledgements The authors acknowledge Arizona State Univer-
sity for the start-up funding support.
Author contributions YZ, DJ, XL wrote the sections of introduction,
summary, and outlook. WS wrote 3D printing of biomimetic lab-on-
chip. YC wrote 3D printing of biomimetic medicine. JR wrote 3D
printing of biomimetic microvascular network. HZ wrote 3D printing of
biomimetic scaffold-based implants. SX wore 3D printing of artificial
organs. All authors discussed and commented on the manuscript.
Compliance with ethical standards
Conflict of interest The authors declare that they have no conflict of
interest.
Ethical approval This review does not contain any studies with human
or animal subjects performed by any of the authors.
References
1. Poukens J, Laeven P, Beerens M, Nijenhuis G, Sloten JV, Stoelinga
P et al (2008) A classification of cranial implants based on the
degree of difficulty in computer design and manufacture. Int J
Med Rob Comput Assisted Surg 4(1):46–50. https://doi.org/10.1
002/rcs.171
2. Yang Y, Song X, Li X, Chen Z, Zhou C, Zhou Q et al (2018) Recent
progress in biomimetic additive manufacturing technology: from
materials to functional structures. Adv Mater. https://doi.org/10.
1002/adma.201706539
3. Leung Y-S, Kwok T-H, Li X, Yang Y, Wang CCL, Chen Y (2019)
Challenges and status on design and computation for emerging
additive manufacturing technologies. J Comput Inf Sci Eng doi
10(1115/1):4041913
123

Bio-Design and Manufacturing (2021) 4:405–428 423
4. Yang Y, Li X, Zheng X, Chen Z, Zhou Q, Chen Y (2018) 3D-
printed biomimetic super-hydrophobic structure for microdroplet
manipulation and oil/water separation. Adv Mater 30(9):1704912.
https://doi.org/10.1002/adma.201704912
5. Li X, Yang Y, Liu L, Chen Y, Chu M, Sun H et al (2020) 3D-
printed cactus-inspired spine structures for highly efficient water
collection. Adv Mater Interfaces 7(3):1901752. https://doi.org/1
0.1002/admi.201901752
6. Li X, Yang Y, Xie B, Chu M, Sun H, Hao S et al (2019) 3D printing
of flexible liquid sensor based on swelling behavior of hydrogel
with carbon nanotubes. Adv Mater Technol 4(2):1800476. https://
doi.org/10.1002/admt.201800476
7. Yang Y, Li X, Chu M, Sun H, Jin J, Yu K et al (2019) Elec-
trically assisted 3D printing of nacre-inspired structures with
self-sensing capability. Sci Adv 5(4):eaau9490. https://doi.org/
10.1126/sciadv.aau9490
8. Ma PX (2008) Biomimetic materials for tissue engineering. Adv
Drug Del Rev 60(2):184–198. https://doi.org/10.1016/j.addr.200
7.08.041
9. Aizenberg J, Fratzl P (2009) Biological and biomimetic materials.
Adv Mater 21(4):387–388. https://doi.org/10.1002/adma.200803
699
10. Fisher OZ, Khademhosseini A, Langer R, Peppas NA (2010)
Bioinspired materials for controlling stem cell fate. Acc Chem
Res 43(3):419–428. https://doi.org/10.1021/ar900226q
11. Kushner AM, Guan Z (2011) Modular design in natu-
ral and biomimetic soft materials. Angew Chem Int Ed
50(39):9026–9057. https://doi.org/10.1002/anie.201006496
12. Holzapfel BM, Reichert JC, Schantz J-T, Gbureck U, Rackwitz
L, Noeth U et al (2013) How smart do biomaterials need to be?
A translational science and clinical point of view. Adv Drug Del
Rev 65(4):581–603. https://doi.org/10.1016/j.addr.2012.07.009
13. Li X, Yuan Y, Liu L, Leung Y-S, Chen Y, Guo Y et al (2020)
3D printing of hydroxyapatite/tricalcium phosphate scaffold with
hierarchical porous structure for bone regeneration. Bio-Des
Manuf 3(1):15–29. https://doi.org/10.1007/s42242-019-00056-5
14. Huang G, Li F, Zhao X, Ma Y, Li Y, Lin M et al (2017) Functional
and biomimetic materials for engineering of the three-dimensional
cell microenvironment. Chem Rev 117(20):12764–12850. https://
doi.org/10.1021/acs.chemrev.7b00094
15. Balakrishnan B, Banerjee R (2011) Biopolymer-based hydrogels
for cartilage tissue engineering. Chem Rev 111(8):4453–4474.
https://doi.org/10.1021/cr100123h
16. Sands RW, Mooney DJ (2007) Polymers to direct cell fate
by controlling the microenvironment. Curr Opin Biotechnol
18(5):448–453. https://doi.org/10.1016/j.copbio.2007.10.004
17. Edalat F, Sheu I, Manoucheri S, Khademhosseini A (2012)
Material strategies for creating artificial cell-instructive niches.
Curr Opin Biotechnol 23(5):820–825. https://doi.org/10.1016/j.
copbio.2012.05.007
18. Yi H-G, Lee H, Cho D-W (2017) 3D printing of organs-on-
chips. Bioengineering (Basel) 4(1):10. https://doi.org/10.3390/
bioengineering4010010
19. Hoffman AS (2012) Hydrogels for biomedical applications. Adv
Drug Del Rev 64:18–23. https://doi.org/10.1016/j.addr.2012.09.
010
20. Caliari SR, Burdick JA (2016) A practical guide to hydrogels for
cell culture. Nat Methods 13(5):405–414. https://doi.org/10.103
8/nmeth.3839
21. DeForest CA, Anseth KS (2012) Advances in bioactive hydrogels
to probe and direct cell fate. In: Prausnitz JM (eds) Annual review
of chemical and biomolecular engineering, vol 3, pp 421–444
22. Faulk DM, Johnson SA, Zhang L, Badylak SF (2014) Role of the
extracellular matrix in whole organ engineering. J Cell Physiol
229(8):984–989. https://doi.org/10.1002/jcp.24532
23. Aamodt JM, Grainger DW (2016) Extracellular matrix-based bio-
material scaffolds and the host response. Biomaterials 86:68–82.
https://doi.org/10.1016/j.biomaterials.2016.02.003
24. Hong S, Sycks D, Chan HF, Lin S, Lopez GP, Guilak F et al
(2015) 3D printing of highly stretchable and tough hydrogels into
complex, cellularized structures. Adv Mater 27(27):4035–4040.
https://doi.org/10.1002/adma.201501099
25. Yi H-G, Kang KS, Hong JM, Jang J, Park MN, Jeong YH et al
(2016) Effects of electromagnetic field frequencies on chondro-
cytes in 3D cell-printed composite constructs. J Biomed Mater
Res A 104(7):1797–1804. https://doi.org/10.1002/jbm.a.35714
26. Lozano R, Stevens L, Thompson BC, Gilmore KJ, Gorkin R III,
Stewart EM et al (2015) 3D printing of layered brain-like struc-
tures using peptide modified gellan gum substrates. Biomaterials
67:264–273. https://doi.org/10.1016/j.biomaterials.2015.07.022
27. Zander NE, Dong H, Steele J, Grant JT (2014) Metal cation cross-
linked nanocellulose hydrogels as tissue engineering substrates.
ACS Appl Mater Interfaces 6(21):18502–18510. https://doi.org/
10.1021/am506007z
28. Zhu J, Kaufman LJ (2014) Collagen I self-assembly: reveal-
ing the developing structures that generate turbidity. Biophys J
106(8):1822–1831. https://doi.org/10.1016/j.bpj.2014.03.011
29. Miao Z, Lu Z, Wu H, Liu H, Li M, Lei D et al (2018) Colla-
gen, agarose, alginate, and Matrigel hydrogels as cell substrates
for culture of chondrocytes in vitro: a comparative study. J Cell
Biochem 119(10):7924–7933. https://doi.org/10.1002/jcb.26411
30. Xiong R, Chai W, Huang Y (2019) Laser printing-enabled direct
creation of cellular heterogeneity in lab-on-a-chip devices. Lab
Chip 19(9):1644–1656. https://doi.org/10.1039/c9lc00117d
31. Martinsen A, Skjakbraek G, Smidsrod O (1989) Alginate as
immobilization material. 1. Correlation between chemical and
physical-properties of alginate gel beads. Biotechnol Bioeng
33(1):79–89. https://doi.org/10.1002/bit.260330111
32. Augst AD, Kong HJ, Mooney DJ (2006) Alginate hydrogels as
biomaterials. Macromol Biosci 6(8):623–633. https://doi.org/10.
1002/mabi.200600069
33. Freeman I, Kedem A, Cohen S (2008) The effect of sulfation of
alginate hydrogels on the specific binding and controlled release
of heparin-binding proteins. Biomaterials 29(22):3260–3268.
https://doi.org/10.1016/j.biomaterials.2008.04.025
34. Madl CM, Mehta M, Duda GN, Heilshorn SC, Mooney DJ
(2014) Presentation of BMP-2 mimicking peptides in 3D hydro-
gels directs cell fate commitment in osteoblasts and mesenchymal
stem cells. Biomacromolecules 15(2):445–455. https://doi.org/1
0.1021/bm401726u
35. Boontheekul T, Kong HJ, Mooney DJ (2005) Controlling alginate
gel degradation utilizing partial oxidation and bimodal molecular
weight distribution. Biomaterials 26(15):2455–2465. https://doi.
org/10.1016/j.biomaterials.2004.06.044
36. Rebelo R, Fernandes M, Fangueiro R (2017) Biopolymers in
medical implants: a brief review. In: Fangueiro R (eds) 3rd inter-
national conference on natural fibers: advanced materials for a
greener world. ICNF 2017, pp 236–243
37. Naumenko EA, Guryanov ID, Yendluri R, Lvov YM, Fakhrullin
RF (2016) Clay nanotube-biopolymer composite scaffolds for tis-
sue engineering. Nanoscale 8(13):7257–7271. https://doi.org/10.
1039/c6nr00641h
38. Stoppel WL, Ghezzi CE, McNamara SL, Black LD III, Kaplan
DL (2015) Clinical applications of naturally derived biopolymer-
based scaffolds for regenerative medicine. Ann Biomed Eng
43(3):657–680. https://doi.org/10.1007/s10439-014-1206-2
39. Jiang Y, Wang Y, Wang H, Zhou L, Gao J, Zhang Y et al
(2015) Facile immobilization of enzyme on three dimensionally
ordered macroporous silica via a biomimetic coating. New J Chem
39(2):978–984. https://doi.org/10.1039/c4nj01947d
123

424 Bio-Design and Manufacturing (2021) 4:405–428
40. Singh D (2018) Investigations on biomimetic PLA scaffold fab-
ricated by fused deposition modelling [D]
41. Lih E, Park KW, Chun SY, Kim H, Kwon TG, Joung YK et al
(2016) Biomimetic porous PLGA scaffolds incorporating decel-
lularized extracellular matrix for kidney tissue regeneration. ACS
Appl Mater Interfaces 8(33):21145–21154. https://doi.org/10.10
21/acsami.6b03771
42. Zhang K, Fu Q, Yoo J, Chen X, Chandra P, Mo X et al (2017)
3D bioprinting of urethra with PCL/PLCL blend and dual autolo-
gous cells in fibrin hydrogel: an in vitro evaluation of biomimetic
mechanical property and cell growth environment. Acta Biomater
50:154–164. https://doi.org/10.1016/j.actbio.2016.12.008
43. Li X, Yang Y, Chen Y (2017) Bio-inspired micro-scale texture
fabrication based on immersed surface accumulation process. In:
World congress on micro and nano manufacturing conference, pp
33–36
44. Li X, Shan W, Yang Y, Joralmon D, Zhu Y, Chen Y, Yuan Y,
Xu H, Rong J, Dai R, Nian Q, Chai Y, Chen Y (2020) Limpet
teeth inspired painless microneedles fabricated by magnetic field
assisted 3D printing. Adv Funct Mater. https://doi.org/10.1002/
adfm.202003725
45. Price PM, Mahmoud WE, Al-Ghamdi AA, Bronstein LM (2018)
Magnetic drug delivery: where the field is going. Front Chem
https://doi.org/10.3389/fchem.2018.00619
46. Ikada Y (2006) Challenges in tissue engineering. J R Soc Interface
3(10):589–601. https://doi.org/10.1098/rsif.2006.0124
47. Ng YC, Berry JM, Butler M (1996) Optimization of physical
parameters for cell attachment and growth on macroporous
microcarriers. Biotechnol Bioeng 50(6):627–635. https://doi.
org/10.1002/(sici)1097-0290(19960620)50:6%3c627:Aid-bit3%
3e3.0.Co;2-m
48. D. Anh-Vu, R. Smith, T. M. Acri, S. M. Geary, A. K. Salem, 3D
printing technologies for 3D scaffold engineering, in: Y. Deng, J.
Kuiper, Functional 3d Tissue Engineering Scaffolds: Materials,
Technologies, and Applications, 2018, pp. 203-234
49. Wang X, Jiang M, Zhou ZW, Gou JH, Hui D (2017) 3D printing
of polymer matrix composites: a review and prospective. Compos
Part B-Eng 110:442–458. https://doi.org/10.1016/j.compositesb.
2016.11.034
50. Zhao P, Gu H, Mi H, Rao C, Fu J, Turng L-S (2018) Fabrica-
tion of scaffolds in tissue engineering: a review. Front Mech Eng
13(1):107–119. https://doi.org/10.1007/s11465-018-0496-8
51. Deville S, Saiz E, Tomsia AP (2006) Freeze casting of hydrox-
yapatite scaffolds for bone tissue engineering. Biomaterials
27(32):5480–5489. https://doi.org/10.1016/j.biomaterials.2006.0
6.028
52. Desimone D, Li W, Roether JA, Schubert DW, Crovace MC,
Rodrigues ACM et al (2013) Biosilicate (R)-gelatine bone scaf-
folds by the foam replica technique: development and character-
ization. Sci Technol Adv Mater 14(4):045008. https://doi.org/10.
1088/1468-6996/14/4/045008
53. Cai Q, Yang JA, Bei JZ, Wang SG (2002) A novel porous
cells scaffold made of polylactide-dextran blend by combining
phase-separation and particle-leaching techniques. Biomaterials
23(23):4483–4492. https://doi.org/10.1016/s0142-9612(02)0016
8-0
54. Mi H-Y, Salick MR, Jing X, Jacques BR, Crone WC,
Peng X-F et al (2013) Characterization of thermoplastic
polyurethane/polylactic acid (TPU/PLA) tissue engineering scaf-
folds fabricated by microcellular injection molding. Mater Sci
Eng C-Mater Biol Appl 33(8):4767–4776. https://doi.org/10.101
6/j.msec.2013.07.037
55. Sin D, Miao X, Liu G, Wei F, Chadwick G, Yan C et al
(2010) Polyurethane (PU) scaffolds prepared by solvent cast-
ing/particulate leaching (SCPL) combined with centrifugation.
Mater Sci Eng C Mater Biol Appl 30(1):78–85. https://doi.org/1
0.1016/j.msec.2009.09.002
56. Lee J, Cuddihy MJ, Kotov NA (2008) Three-dimensional cell cul-
ture matrices: state of the art. Tissue Eng Part B-Rev 14(1):61–86.
https://doi.org/10.1089/teb.2007.0150
57. Sopyan I, Mel M, Ramesh S, Khalid KA (2007) Porous hydrox-
yapatite for artificial bone applications. Sci Technol Adv Mater
8(1–2):116–123. https://doi.org/10.1016/j.stam.2006.11.017
58. Baji A, Wong SC, Srivatsan TS, Njus GO, Mathur G (2006)
Processing methodologies for polycaprolactone–hydroxyapatite
composites: a review. Mater Manuf Processes 21(2):211–218.
https://doi.org/10.1081/amp-200068681
59. Hwang YK, Jeong U, Cho EC (2008) Production of uniform-sized
polymer core–shell microcapsules by coaxial electrospraying.
Langmuir 24(6):2446–2451. https://doi.org/10.1021/la703546f
60. Huang K, Hou J, Gu Z, Wu J (2019) Egg-white-/eggshell-
based biomimetic hybrid hydrogels for bone regeneration. ACS
Biomater Sci Eng 5(10):5384–5391. https://doi.org/10.1021/
acsbiomaterials.9b00990
61. Feng C, Zhang W, Deng C, Li G, Chang J, Zhang Z et al (2017) 3D
printing of lotus root-like biomimetic materials for cell delivery
and tissue regeneration. Adv Sci 4(12):1700401. https://doi.org/
10.1002/advs.201700401
62. Zhang M, Lin RC, Wang X, Xue JM, Deng CJ, Feng C et al (2020)
3D printing of Haversian bone-mimicking scaffolds for multi-
cellular delivery in bone regeneration. Sci Adv 6(12):eaaz6725.
https://doi.org/10.1126/sciadv.aaz6725
63. Kim W, Kim M, Kim GH (2018) 3D-printed biomimetic scaf-
fold simulating microfibril muscle structure. Adv Funct Mater
28(26):1800405. https://doi.org/10.1002/adfm.201800405
64. Melchels FPW, Feijen J, Grijpma DW (2010) A review on
stereolithography and its applications in biomedical engineer-
ing. Biomaterials 31(24):6121–6130. https://doi.org/10.1016/j.
biomaterials.2010.04.050
65. Koffler J, Zhu W, Qu X, Platoshyn O, Dulin JN, Brock J et al
(2019) Biomimetic 3D-printed scaffolds for spinal cord injury
repair. Nat Med 25(2):263. https://doi.org/10.1038/s41591-018-0
296-z
66. Li X, Baldacchin T, Song X, Chen Y (2016) Multi-scale additive
manufacturing: an investigation on building objects with macro-,
micro-and nano-scales features. In: The 11th international con-
ference on micro manufacturing
67. Li X, Chen Y (2017) Micro-scale feature fabrication using
immersed surface accumulation. J Manuf Proces 28:531–540.
https://doi.org/10.1016/j.jmapro.2017.04.022
68. Li X, Chen Y (2018) Multi-scale 3D printing of bioinspired struc-
tures with functional surfaces. In: Proceedings of the international
symposium on flexible automation. The Institute of Systems, Con-
trol and Information Engineers, pp 13–20
69. Jang J, Yi H-G, Cho D-W (2016) 3D printed tissue models: present
and future. ACS Biomater Sci Eng 2(10):1722–1731. https://doi.
org/10.1021/acsbiomaterials.6b00129
70. Seok J, Warren HS, Cuenca AG, Mindrinos MN, Baker HV,
Xu W et al (2013) Genomic responses in mouse models poorly
mimic human inflammatory diseases. Proc Natl Acad Sci USA
110(9):3507–3512. https://doi.org/10.1073/pnas.1222878110
71. Huh D, Torisawa Y-S, Hamilton GA, Kim HJ, Ingber DE
(2012) Microengineered physiological biomimicry: organs-on-
Chips. Lab Chip 12(12):2156–2164. https://doi.org/10.1039/c2
lc40089h
72. Ingber DE, Mow VC, Butler D, Niklason L, Huard J, Mao J
et al (2006) Tissue engineering and developmental biology: going
biomimetic. Tissue Eng 12(12):3265–3283. https://doi.org/10.10
89/ten.2006.12.3265
123

Bio-Design and Manufacturing (2021) 4:405–428 425
73. Hussey GS, Dziki JL, Badylak SF (2018) Extracellular matrix-
based materials for regenerative medicine. Nat Rev Mater
3(7):159–173. https://doi.org/10.1038/s41578-018-0023-x
74. Moroni L, Burdick JA, Highley C, Lee SJ, Morimoto Y, Takeuchi
S et al (2018) Biofabrication strategies for 3D in vitro models and
regenerative medicine. Nat Rev Mater 3(5):21–37. https://doi.org/
10.1038/s41578-018-0006-y
75. Zhu W, Ma X, Gou M, Mei D, Zhang K, Chen S (2016) 3D
printing of functional biomaterials for tissue engineering. Curr
Opin Biotechnol 40:103–112. https://doi.org/10.1016/j.copbio.2
016.03.014
76. Stone HA, Stroock AD, Ajdari A (2004) Engineering flows in
small devices: microfluidics toward a lab-on-a-chip. Annu Rev
Fluid Mech 36:381–411. https://doi.org/10.1146/annurev.fluid.3
6.050802.122124
77. Dittrich PS, Manz A (2006) Lab-on-a-chip: microfluidics in drug
discovery. Nat Rev Drug Discovery 5(3):210–218. https://doi.org/
10.1038/nrd1985
78. Sosa-Hernandez JE, Villalba-Rodriguez AM, Romero-Castillo
KD, Aguilar-Aguila-Isaias MA, Garcia-Reyes IE, Hernandez-
Antonio A et al (2018) Organs-on-a-chip module: a review from
the development and applications perspective. Micromachines
9(10):536. https://doi.org/10.3390/mi9100536
79. Oliveira NM, Vilabril S, Oliveira MB, Reis RL, Mano JF (2019)
Recent advances on open fluidic systems for biomedical applica-
tions: a review. Mater Sci Eng C Mater Biol Appl 97:851–863.
https://doi.org/10.1016/j.msec.2018.12.040
80. Robinson TF, Cohengould L, Factor SM (1983) Skeletal frame-
work of mammalian heart-muscle: arrangement of inter and peri-
cellular connective-tissue structures. Lab Invest 49(4):482–498
81. Kim D-H, Lipke EA, Kim P, Cheong R, Thompson S, Delannoy
M et al (2010) Nanoscale cues regulate the structure and function
of macroscopic cardiac tissue constructs. Proc Natl Acad Sci USA
107(2):565–570. https://doi.org/10.1073/pnas.0906504107
82. Feng Z-Q, Chu X, Huang N-P, Wang T, Wang Y, Shi X et al
(2009) The effect of nanofibrous galactosylated chitosan scaffolds
on the formation of rat primary hepatocyte aggregates and the
maintenance of liver function. Biomaterials 30(14):2753–2763.
https://doi.org/10.1016/j.biomaterials.2009.01.053
83. De Jaeghere E, De Vlieghere E, Van Hoorick J, Van Vlierberghe
S, Wagemans G, Pieters L et al (2018) Heterocellular 3D scaffolds
as biomimetic to recapitulate the tumor microenvironment of peri-
toneal metastases in vitro and in vivo. Biomaterials 158:95–105.
https://doi.org/10.1016/j.biomaterials.2017.12.017
84. Ma X, Qu X, Zhu W, Li Y-S, Yuan S, Zhang H et al (2016)
Deterministically patterned biomimetic human iPSC-derived hep-
atic model via rapid 3D bioprinting. Proc Natl Acad Sci USA
113(8):2206–2211. https://doi.org/10.1073/pnas.1524510113
85. Park JY, Ryu H, Lee B, Ha D-H, Ahn M, Kim S et al (2019)
Development of a functional airway-on-a-chip by 3D cell printing.
Biofabrication 11(1):015002. https://doi.org/10.1088/1758-5090/
aae545
86. Kim BS, Lee J-S, Gao G, Cho D-W (2017) Direct 3D cell-printing
of human skin with functional transwell system. Biofabrication
9(2):025034. https://doi.org/10.1088/1758-5090/aa71c8
87. Bazaz SR, Rouhi O, Raoufi MA et al (2020) 3D printing of inertial
microfluidic devices[J]. Sci Rep 10(1):1–14. https://doi.org/10.1
038/s41598-020-62569-9
88. Katseli V, Economou A, Kokkinos C (2020) A novel all-3D-
printed cell-on-a-chip device as a useful electroanalytical tool:
application to the simultaneous voltammetric determination of
caffeine and paracetamol. Talanta 208:120388. https://doi.org/1
0.1016/j.talanta.2019.120388
89. Magin CM, Alge DL, Anseth KS (2016) Bio-inspired 3D microen-
vironments: a new dimension in tissue engineering. Biomed Mater
11(2):022001. https://doi.org/10.1088/1748-6041/11/2/022001
90. Sharafeldin M, Jones A, Rusling JF (2018) 3D-printed biosensor
arrays for medical diagnostics. Micromachines 9(8):394. https://
doi.org/10.3390/mi9080394
91. Sapudom J, Pompe T (2018) Biomimetic tumor microenviron-
ments based on collagen matrices. Biomater Sci 6(8):2009–2024.
https://doi.org/10.1039/c8bm00303c
92. Gill EL, Li X, Birch MA, Huang YYS (2018) Multi-length scale
bioprinting towards simulating microenvironmental cues. Bio-
Des Manuf 1(2):77–88. https://doi.org/10.1007/s42242-018-001
4-1
93. Gladman AS, Matsumoto EA, Nuzzo RG, Mahadevan L, Lewis
JA (2016) Biomimetic 4D printing. Nat Mater 15(4):413. https://
doi.org/10.1038/nmat4544
94. Gao B, Yang Q, Zhao X, Jin G, Ma Y, Xu F (2016) 4D bioprinting
for biomedical applications. Trends Biotechnol 34(9):746–756.
https://doi.org/10.1016/j.tibtech.2016.03.004
95. Trenfield SJ, Awad A, Goyanes A, Gaisford S, Basit AW (2018)
3D printing pharmaceuticals: drug development to frontline care.
Trends Pharmacol Sci 39(5):440–451. https://doi.org/10.1016/j.
tips.2018.02.006
96. Awad A, Trenfield SJ, Gaisford S, Basit AW (2018) 3D printed
medicines: a new branch of digital healthcare. Int J Pharm
548(1):586–596. https://doi.org/10.1016/j.ijpharm.2018.07.024
97. Collins FS, Varmus H (2015) A new initiative on precision
medicine. New Engl J Med 372(9):793–795. https://doi.org/10.
1056/NEJMp1500523
98. Bittner SM, Guo JL, Mikos AG (2018) Spatiotemporal control of
growth factors in three-dimensional printed scaffolds. Bioprinting
(Amsterdam, Netherlands) 12:e00032. https://doi.org/10.1016/j.
bprint.2018.e00032
99. Gao G, Cui X (2016) Three-dimensional bioprinting in tis-
sue engineering and regenerative medicine. Biotech Lett
38(2):203–211. https://doi.org/10.1007/s10529-015-1975-1
100. Ozbolat IT, Hospodiuk M (2016) Current advances and
future perspectives in extrusion-based bioprinting. Biomaterials
76:321–343. https://doi.org/10.1016/j.biomaterials.2015.10.076
101. Ceylan H, Yasa IC, Yasa O, Tabak AF, Giltinan J, Sitti M (2019)
3D-printed biodegradable microswimmer for theranostic cargo
delivery and release. ACSNano 13(3):3353–3362. https://doi.org/
10.1021/acsnano.8b09233
102. Zhu W, Li J, Leong YJ, Rozen I, Qu X, Dong R et al (2015) 3D-
printed artificial microfish. Adv Mater 27(30):4411–4417. https://
doi.org/10.1002/adma.201501372
103. Wang XP, Chen XZ, Alcantara CCJ, Sevim S, Hoop M, Ter-
zopoulou A et al (2019) MOFBOTS: metal-organic-framework-
based biomedical microrobots. Adv Mater. https://doi.org/10.100
2/adma.201901592
104. Oblom H, Zhang JX, Pimparade M, Speer I, Preis M, Repka M
et al (2019) 3D-printed isoniazid tablets for the treatment and
prevention of tuberculosis personalized dosing and drug release.
Aaps Pharmscitech 20(2):52. https://doi.org/10.1208/s12249-01
8-1233-7
105. Khaled SA, Alexander MR, Irvine DJ, Wildman RD, Wallace
MJ, Sharpe S et al (2018) Extrusion 3D printing of parac-
etamol tablets from a single formulation with tunable release
profiles through control of tablet geometry. AAPS PharmSciTech
19(8):3403–3413. https://doi.org/10.1208/s12249-018-1107-z
106. Wang YZ, Miao Y, Zhang JL, Wu JP, Kirk TB, Xu JK et al
(2018) Three-dimensional printing of shape memory hydrogels
with internal structure for drug delivery. Mater Sci Eng C-Mater
Biol Appl 84:44–51. https://doi.org/10.1016/j.msec.2017.11.025
107. Clark EA, Alexander MR, Irvine DJ, Roberts CJ, Wallacec MJ,
Sharpe S et al (2017) 3D printing of tablets using inkjet with UV
photoinitiation. Int J Pharm 529(1–2):523–530. https://doi.org/1
0.1016/j.ijpharm.2017.06.085
123

426 Bio-Design and Manufacturing (2021) 4:405–428
108. Awad A, Fina F, Trenfield SJ, Patel P, Goyanes A, Gaisford S
et al (2019) 3D printed pellets (miniprintlets): a novel, multi-drug,
controlled release platform technology. Pharmaceutics 11(4):148.
https://doi.org/10.3390/pharmaceutics11040148
109. Richbourg NR, Peppas NA, Sikavitsas VI (2019) Tuning the
biomimetic behavior of scaffolds for regenerative medicine
through surface modifications. J Tissue Eng Regener Med
13(8):1275–1293. https://doi.org/10.1002/term.2859
110. Bloomquist CJ, Mecham MB, Paradzinsky MD, Janusziewicz R,
Warner SB, Luft JC et al (2018) Controlling release from 3D
printed medical devices using CLIP and drug-loaded liquid resins.
J Control Rel 278:9–23. https://doi.org/10.1016/j.jconrel.2018.0
3.026
111. Lee J, Lee S-H, Lee B-K, Park S-H, Cho Y-S, Park Y (2018)
Fabrication of microchannels and evaluation of guided vascu-
larization in biomimetic hydrogels. Tissue Eng Regener Med
15(4):403–413. https://doi.org/10.1007/s13770-018-0130-1
112. Hall H (2007) Modified fibrin hydrogel matrices: both, 3D-
scaffolds and local and controlled release systems to stimulate
angiogenesis. Curr Pharm Des 13(35):3597–3607. https://doi.org/
10.2174/138161207782794158
113. Suzuki M, Sawa T, Takahashi T, Aoyagi S, IEEE (2015) Ultra-
fine three-dimensional (3D) laser lithographic fabrication of
microneedle and its application to painless insertion and blood
sampling inspired by mosquito. In: 2015 IEEE/RSJ international
conference on intelligent robots and systems, pp 2748–2753
114. Liaw C-Y, Guvendiren M (2017) Current and emerging appli-
cations of 3D printing in medicine. Biofabrication 9(2):024102.
https://doi.org/10.1088/1758-5090/aa7279
115. Goyanes A, Buanz ABM, Basit AW, Gaisford S (2014) Fused-
filament 3D printing (3DP) for fabrication of tablets. Int J Pharm
476(1–2):88–92. https://doi.org/10.1016/j.ijpharm.2014.09.044
116. Skowyra J, Pietrzak K, Alhnan MA (2015) Fabrication of
extended-release patient-tailored prednisolone tablets via fused
deposition modelling (FDM) 3D printing. Eur J Pharm Sci
68:11–17. https://doi.org/10.1016/j.ejps.2014.11.009
117. Sandler N, Salmela I, Fallarero A, Rosling A, Khajeheian M,
Kolakovic R et al (2014) Towards fabrication of 3D printed
medical devices to prevent biofilm formation. Int J Pharm
459(1–2):62–64. https://doi.org/10.1016/j.ijpharm.2013.11.001
118. Weisman JA, Nicholson JC, Tappa K, Jammalamadaka U, Wilson
CG, Mills DK (2015) Antibiotic and chemotherapeutic enhanced
three-dimensional printer filaments and constructs for biomedical
applications. Int J Nanomed 10:357–370. https://doi.org/10.2147/
ijn.S74811
119. Moulton SE, Wallace GG (2014) 3-dimensional (3D) fabri-
cated polymer based drug delivery systems. J Controll Release
193:27–34. https://doi.org/10.1016/j.jconrel.2014.07.005
120. Postiglione G, Alberini M, Leigh S, Levi M, Turri S (2017) Effect
of 3D-printed microvascular network design on the self-healing
behavior of cross-linked polymers. ACS Appl Mater Interfaces
9(16):14371–14378. https://doi.org/10.1021/acsami.7b01830
121. Karam GN (2005) Biomechanical model of the xylem vessels in
vascular plants. Ann Bot 95(7):1179–1186. https://doi.org/10.10
93/aob/mci130
122. Knight C (1981) Pressure component construction… design and
materials application. Taylor and Francis, London
123. Bader MG, Smith W, Isham AB, Rolston J (1990) Delaware
composites design encyclopedia. vol. 3: processing and fabrica-
tion technology. Technomic Publishing Company, Lancaster, PA
(1990)
124. Shevchenko YN, Merzlyakov VA, Galishin AZ, Novikov SV,
Los AO, Yukhimets PS (1993) Determination of the limiting
stress-strain state of helically corrugated pipes. Strength Mater
25(7):507–511. https://doi.org/10.1007/bf00775128
125. Hoballah JJ (2000) Vascular reconstructions: anatomy, exposures
and techniques. Springer, Berlin
126. Lei D, Yang Y, Liu Z, Yang B, Gong W, Chen S et al (2019) 3D
printing of biomimetic vasculature for tissue regeneration. Mater
Horizons 6(6):1197–1206. https://doi.org/10.1039/c9mh00174c
127. Dean LM, Krull BP, Li KR, Fedonina YI, White SR, Sottos NR
(2018) Enhanced mixing of microvascular self-healing reagents
using segmented gas-liquid flow. ACS Appl Mater Interfaces
10(38):32659–32667. https://doi.org/10.1021/acsami.8b09966
128. Kim S-R, Getachew BA, Kim J-H (2017) Toward microvascu-
lar network-embedded self-healing membranes. J Membr Sci
531:94–102. https://doi.org/10.1016/j.memsci.2017.02.038
129. Yu F, Choudhury D (2019) Microfluidic bioprinting for organ-on-
a-chip models. Drug Discov Today 24(6):1248–1257. https://doi.
org/10.1016/j.drudis.2019.03.025
130. Fedorovich NE, Alblas J, de Wijn JR, Hennink WE, Verbout AJ,
Dhert WJA (2007) Hydrogels as extracellular matrices for skeletal
tissue engineering: state-of-the-art and novel application in organ
printing. Tissue Eng 13(8):1905–1925. https://doi.org/10.1089/
ten.2006.0175
131. Norotte C, Marga FS, Niklason LE, Forgacs G (2009) Scaffold-
free vascular tissue engineering using bioprinting. Biomaterials
30(30):5910–5917. https://doi.org/10.1016/j.biomaterials.2009.0
6.034
132. Kinstlinger IS, Miller JS (2016) 3D-printed fluidic networks as
vasculature for engineered tissue. Lab Chip 16(11):2025–2043.
https://doi.org/10.1039/c6lc00193a
133. Murphy SV, Atala A (2014) 3D bioprinting of tissues and organs.
Nat Biotechnol 32(8):773–785. https://doi.org/10.1038/nbt.2958
134. Knowlton S, Onal S, Yu CH, Zhao JJ, Tasoglu S (2015) Bioprint-
ing for cancer research. Trends Biotechnol 33(9):504–513. https://
doi.org/10.1016/j.tibtech.2015.06.007
135. Ho CMB, Sum Huan N, Li KHH, Yoon Y-J (2015) 3D
printed microfluidics for biological applications. Lab Chip
15(18):3627–3637. https://doi.org/10.1039/c5lc00685f
136. Wu W, DeConinck A, Lewis JA (2011) Omnidirectional printing
of 3D microvascular networks. Adv Mater 23(24):H178–H183.
https://doi.org/10.1002/adma.201004625
137. Bhattacharjee T, Zehnder SM, Rowe KG, Jain S, Nixon RM,
Sawyer WG et al (2015) Writing in the granular gel medium.
Sci Adv 1(8):e1500655. https://doi.org/10.1126/sciadv.1500655
138. Bertassoni LE, Cecconi M, Manoharan V, Nikkhah M, Hjortnaes
J, Cristino AL et al (2014) Hydrogel bioprinted microchannel
networks for vascularization of tissue engineering constructs. Lab
Chip 14(13):2202–2211. https://doi.org/10.1039/c4lc00030g
139. Gao G, Kim H, Kim BS, Kong JS, Lee JY, Park BW et al (2019)
Tissue-engineering of vascular grafts containing endothelium and
smooth-muscle using triple-coaxial cell printing. Appl Phys Rev
6(4):041402. https://doi.org/10.1063/1.5099306
140. Grigoryan B, Paulsen SJ, Corbett DC, Sazer DW, Fortin CL, Zaita
AJ et al (2019) BIOMEDICINE Multivascular networks and func-
tional intravascular topologies within biocompatible hydrogels.
Science 364(6439):458. https://doi.org/10.1126/science.aav9750
141. Kim SH, Yeon YK, Lee JM, Chao JR, Lee YJ, Seo YB et al
(2018) Precisely printable and biocompatible silk fibroin bioink
for digital light processing 3D printing. Nat Commun. https://doi.
org/10.1038/s41467-018-03759-y
142. Datta P, Ayan B, Ozbolat IT (2017) Bioprinting for vascular
and vascularized tissue biofabrication. Acta Biomater 51:1–20.
https://doi.org/10.1016/j.actbio.2017.01.035
143. Li X, Mao H, Pan Y, Chen Y (2019) Mask video projection-based
stereolithography with continuous resin flow. J Manuf Sci Eng
Trans ASME 141(8):081007. https://doi.org/10.1115/1.4043765
144. Chen Y, Mao H, Li X (2016) Mask video projection based
stereolithography with continuous resin flow. U.S. Patent
10,308,007[P]. 2019-6-4
123

Bio-Design and Manufacturing (2021) 4:405–428 427
145. Chen Y, Li X (2018) Surface projection tool for multi-axis additive
manufacturing. U.S. Patent Application 15/868,891[P]. 2018-7-
12
146. Chiu YC, Shen YF, Lee AKX, Lin SH, Wu YC, Chen YW
(2019) 3D printing of amino resin-based photosensitive materials
on multi-parameter optimization design for vascular engineer-
ing applications. Polymers 11(9):1394. https://doi.org/10.3390/
polym11091394
147. Zhang Z, Wang B, Hui D, Qiu J, Wang S (2017) 3D bioprinting
of soft materials-based regenerative vascular structures and tis-
sues. Compos Part B Eng 123:279–291. https://doi.org/10.1016/
j.compositesb.2017.05.011
148. Hospodiuk M, Dey M, Sosnoski D, Ozbolat IT (2017) The bioink:
a comprehensive review on bioprintable materials. Biotechnol
Adv 35(2):217–239. https://doi.org/10.1016/j.biotechadv.2016.1
2.006
149. Gungor-Ozkerim PS, Inci I, Zhang YS, Khademhosseini A,
Dokmeci MR (2018) Bioinks for 3D bioprinting: an overview.
Biomater Sci 6(5):915–946. https://doi.org/10.1039/c7bm00765
e
150. Burdick JA, Prestwich GD (2011) Hyaluronic acid hydrogels for
biomedical applications. Adv Mater 23(12):H41–H56. https://doi.
org/10.1002/adma.201003963
151. Choudhury D, Tun HW, Wang T, Naing MW (2018) Organ-
derived decellularized extracellular matrix: a game changer for
bioink manufacturing? Trends Biotechnol 36(8):787–805. https://
doi.org/10.1016/j.tibtech.2018.03.003
152. Yoo S-S (2015) 3D-printed biological organs: medical potential
and patenting opportunity. Expert Opin Ther Pat 25(5):507–511.
https://doi.org/10.1517/13543776.2015.1019466
153. Colla G, Porto LM (2014) Development of artificial blood ves-
sels through tissue engineering. In: BMC proceedings. 8. BioMed
Central, P45
154. Kapalczynska M, Kolenda T, Przybyla W, Zajaczkowska M,
Teresiak A, Filas V et al (2018) 2D and 3D cell cultures: a com-
parison of different types of cancer cell cultures. Arch Med Sci
14(4):910–919. https://doi.org/10.5114/aoms.2016.63743
155. Park JY, Jang J, Kang H-W (2018) 3D Bioprinting and its appli-
cation to organ-on-a-chip. Microelectron Eng 200:1–11. https://
doi.org/10.1016/j.mee.2018.08.004
156. Mironov V, Kasyanov V, Drake C, Markwald RR (2008) Organ
printing: promises and challenges. Regener Med 3(1):93–103.
https://doi.org/10.2217/17460751.3.1.93
157. Schubert C, van Langeveld MC, Donoso LA (2014) Innovations in
3D printing: a 3D overview from optics to organs.Br J Ophthalmol
98(2):159–161. https://doi.org/10.1136/bjophthalmol-2013-3044
46
158. Zhao H, Chen Y, Shao L, Xie M, Nie J, Qiu J et al (2018) Airflow-
assisted 3D bioprinting of human heterogeneous microspheroidal
organoids with microfluidic nozzle. Small 14(39):1802630.
https://doi.org/10.1002/smll.201802630
159. Zhu L, Li Y, Zhang Q, Wang H, Zhu M (2010) Fabrication of
monodisperse, large-sized, functional biopolymeric microspheres
using a low-cost and facile microfluidic device. Biomed Microdev
12(1):169–177. https://doi.org/10.1007/s10544-009-9373-x
160. Cai B, Guo F, Zhao L, He R, Chen B, He Z et al (2014) Disk-like
hydrogel bead-based immunofluorescence staining toward iden-
tification and observation of circulating tumor cells. Microfluid
Nanofluid 16(1–2):29–37. https://doi.org/10.1007/s10404-013-1
198-5
161. Kim BS, Gao G, Kim JY, Cho D-W (2019) 3D cell printing of
perfusable vascularized human skin equivalent composed of epi-
dermis, dermis, and hypodermis for better structural recapitulation
of native skin. Adv Healthc Mater 8(7):1801019. https://doi.org/
10.1002/adhm.201801019
162. Binder KW, Zhao W, Aboushwareb T, Dice D, Atala A, Yoo JJ
(2010) In situ bioprinting of the skin for burns. J Am Coll Surg
211(3):S76. https://doi.org/10.1016/j.jamcollsurg.2010.06.198
163. Lee V, Singh G, Trasatti JP, Bjornsson C, Xu X, Thanh
Nga T et al (2014) Design and fabrication of human skin
by three-dimensional bioprinting. Tissue Eng Part C-Methods
20(6):473–484. https://doi.org/10.1089/ten.tec.2013.0335
164. Skardal A, Mack D, Kapetanovic E, Atala A, Jackson JD, Yoo J
et al (2012) Bioprinted amniotic fluid-derived stem cells accel-
erate healing of large skin wounds. Stem Cells Transl Med
1(11):792–802. https://doi.org/10.5966/sctm.2012-0088
165. Cubo N, Garcia M, del Canizo JF, Velasco D, Jorcano JL (2017)
3D bioprinting of functional human skin: production and in vivo
analysis. Biofabrication 9(1):015006. https://doi.org/10.1088/17
58-5090/9/1/015006
166. Miriyev A, Stack K, Lipson H (2017) Soft material for soft actu-
ators. Nat Commun 8(1):1–8. https://doi.org/10.1038/s41467-01
7-00685-3
167. Isaacson A, Swioklo S, Connon CJ (2018) 3D bioprinting of a
corneal stroma equivalent. Exp Eye Res 173:188–193. https://
doi.org/10.1016/j.exer.2018.05.010
168. Adams F, Qiu T, Mark A, Fritz B, Kramer L, Schlager D et al
(2017) Soft 3D-printed phantom of the human kidney with col-
lecting system. Ann Biomed Eng 45(4):963–972. https://doi.org/
10.1007/s10439-016-1757-5
169. Noor N, Shapira A, Edri R, Gal I, Wertheim L, Dvir T (2019) 3D
printing of personalized thick and perfusable cardiac patches and
hearts. Adv Sci 6(11):1900344. https://doi.org/10.1002/advs.201
900344
170. Edri R, Gal I, Noor N, Harel T, Fleischer S, Adadi N et al (2019)
Personalized hydrogels for engineering diverse fully autologous
tissue implants. Adv Mater 31(1):1803895. https://doi.org/10.10
02/adma.201803895
171. Yang Y, Chen ZY, Song X, Zhang ZF, Zhang J, Shung KK
et al (2017) Biomimetic anisotropic reinforcement architectures
by electrically assisted nanocomposite 3D printing. Adv Mater
29(11):1605750. https://doi.org/10.1002/adma.201605750
172. Chen YW, Zhang JM, Liu X, WangS, Tao J, Huang YL et al (2020)
Noninvasive in vivo 3D bioprinting. Sci Adv 6(23):eaba7406.
https://doi.org/10.1126/sciadv.aba7406
173. Seol Y-J, Kang H-W, Lee SJ, Atala A, Yoo JJ (2014) Bioprint-
ing technology and its applications. Eur J Cardiothorac Surg
46(3):342–348. https://doi.org/10.1093/ejcts/ezu148
174. Zell K, Sperl JI, Vogel MW, Niessner R, Haisch C (2007) Acousti-
cal properties of selected tissue phantom materials for ultrasound
imaging. Phys Med Biol 52(20):N475–N484. https://doi.org/10.
1088/0031-9155/52/20/n02
175. Elias H, Bengelsdorf H (1952) The structure of the liver of verte-
brates. Cells Tissues Organs 14(4):297–337
176. Abdel-Misih SRZ, Bloomston M (2010) Liver anatomy. Surg Clin
N Am 90(4):643. https://doi.org/10.1016/j.suc.2010.04.017
177. Yun W, Zhi Yuan L, Wenger AC, Tam KC, Xiaowu T (2018)
3D bioprinting of liver-mimetic construct with alginate/cellulose
nanocrystal hybrid bioink. Bioprinting 9:1–6. https://doi.org/10.
1016/j.bprint.2017.12.001
178. Xu F, Kang T, Deng J, Liu J, Chen X, Wang Y et al (2016) Func-
tional nanoparticles activate a decellularized liver scaffold for
blood detoxification. Small 12(15):2067–2076. https://doi.org/1
0.1002/smll.201503320
179. Villar G, Graham AD, BayleyH (2013) A tissue-like printed mate-
rial. Science 340(6128):48–52. https://doi.org/10.1126/science.1
229495
180. Gurkan UA, El Assal R, Yildiz SE, Sung Y, Trachtenberg AJ, Kuo
WP et al (2014) Engineering anisotropic biomimetic fibrocarti-
lage microenvironment by bioprinting mesenchymal stem cells in
123

428 Bio-Design and Manufacturing (2021) 4:405–428
nanoliter gel droplets. Mol Pharm 11(7):2151–2159. https://doi.
org/10.1021/mp400573g
181. Moon S, Hasan SK, Song YS, Xu F, Keles HO, Manzur F
et al (2010) Layer by layer three-dimensional tissue epitaxy
by cell-laden hydrogel droplets. Tissue Eng Part C-Methods
16(1):157–166. https://doi.org/10.1089/ten.tec.2009.0179
182. Guillotin B, Guillemot F (2011) Cell patterning technologies for
organotypic tissue fabrication. Trends Biotechnol 29(4):183–190.
https://doi.org/10.1016/j.tibtech.2010.12.008
183. Ferris CJ, Gilmore KG, WallaceGG, Panhuis MIH (2013) Biofab-
rication: an overview of the approaches used for printing of living
cells. Appl Microbiol Biotechnol 97(10):4243–4258. https://doi.
org/10.1007/s00253-013-4853-6
184. Skardal A, Atala A (2015) Biomaterials for Integration with 3-D
bioprinting. Ann Biomed Eng 43(3):730–746. https://doi.org/10.
1007/s10439-014-1207-1
185. Arslan-Yildiz A, El Assal R, Chen P, Guven S, Inci F, Demirci U
(2016) Towards artificial tissue models: past, present, and future
of 3D bioprinting. Biofabrication 8(1):014103. https://doi.org/10.
1088/1758-5090/8/1/014103
186. Hribar KC, Soman P, Warner J, Chung P, Chen S (2014) Light-
assisted direct-write of 3D functional biomaterials. Lab Chip
14(2):268–275. https://doi.org/10.1039/c3lc50634g
187. Gruene M, Deiwick A, Koch L, Schlie S, Unger C, Hofmann
N et al (2011) Laser printing of stem cells for biofabrication
of scaffold-free autologous grafts. Tissue Eng Part C-Methods
17(1):79–87. https://doi.org/10.1089/ten.tec.2010.0359
188. Koch L, Kuhn S, Sorg H, Gruene M, Schlie S, Gaebel R et al
(2010) Laser printing of skin cells and human stem cells. Tissue
Eng Part C-Methods 16(5):847–854. https://doi.org/10.1089/ten.
tec.2009.0397
189. Malda J, Visser J, Melchels FP, Juengst T, Hennink WE, Dhert
WJA et al (2013) 25th anniversary article: engineering hydrogels
for biofabrication. Adv Mater 25(36):5011–5028. https://doi.org/
10.1002/adma.201302042
190. Ozbolat IT, Yu Y (2013) Bioprinting toward organ fabrica-
tion: challenges and future trends. IEEE Trans Biomed Eng
60(3):691–699. https://doi.org/10.1109/tbme.2013.2243912
191. Shim J-H, Lee J-S, Kim JY, Cho D-W (2012) Bioprinting of a
mechanically enhanced three-dimensional dual cell-laden con-
struct for osteochondral tissue engineering using a multi-head tis-
sue/organ building system. J Micromech Microeng 22(8):085014.
https://doi.org/10.1088/0960-1317/22/8/085014
192. Ringeisen BR, Kim H, Barron JA, Krizman DB, Chrisey DB,
Jackman S et al (2004) Laser printing of pluripotent embryonal
carcinoma cells. Tissue Eng 10(3–4):483–491. https://doi.org/10.
1089/107632704323061843
193. Derakhshanfar S, Mbeleck R, Xu K, Zhang X, Zhong W, Xing
M (2018) 3D bioprinting for biomedical devices and tissue engi-
neering: a review of recent trends and advances. Bioactive Mater
3(2):144–156. https://doi.org/10.1016/j.bioactmat.2017.11.008
194. Chen Z, Wu Y, Yang Y, Li J, Xie B, Li X et al (2018) Multilayered
carbon nanotube yarn based optoacoustic transducer with high
energy conversion efficiency for ultrasound application. Nano
Energy 46:314–321. https://doi.org/10.1016/j.nanoen.2018.02.00
6
195. Zhang J, Yang Y, Zhu B, Li X, Jin J, Chen Z et al (2018) Multifocal
point beam forming by a single ultrasonic transducer with 3D
printed holograms. Appl Phys Lett 113(24):243502. https://doi.
org/10.1063/1.5058079
196. Xiangjia L, Benshuai X, Jie J, Yang C, Yong C (2018) 3D print-
ing temporary crown and bridge by temperature controlled mask
image projection stereolithography. Proc Manuf 26:1023–1033.
https://doi.org/10.1016/j.promfg.2018.07.134
197. Sears NA, Seshadri DR, Dhavalikar PS, Cosgriff-Hernandez E
(2016) A review of three-dimensional printing in tissue engineer-
ing. Tissue Eng Part B-Rev 22(4):298–310. https://doi.org/10.10
89/ten.teb.2015.0464
198. Shusteff M, Browar AE, Kelly BE, Henriksson J, Weisgraber TH,
Panas RM, Fang N, Spadaccini CM (2017) One-step volumetric
additive manufacturing of complex polymer structures. Sci Adv
3(12):eaao5496. https://doi.org/10.1126/sciadv.aao5496
199. Kelly BE, Bhattacharya I, Heidari H, Shusteff M, Spadaccini CM,
Taylor HK (2019) Volumetric additive manufacturing via tomo-
graphic reconstruction. Science 363(6431):1075–1079. https://
doi.org/10.1126/science.aau7114
200. Castro NJ, O’Brien J, Zhang LG (2015) Integrating biolog-
ically inspired nanomaterials and table-top stereolithography
for 3D printed biomimetic osteochondral scaffolds. Nanoscale
7(33):14010–14022. https://doi.org/10.1039/c5nr03425f
201. Cheng CH, Chen YW, Lee AKX, Yao CH, Shie MY (2019) Devel-
opment of mussel-inspired 3D-printed poly(lactic acid) scaffold
grafted with bone morphogenetic protein-2 for stimulating osteo-
genesis. J Mater Sci Mater Med 30(7):78. https://doi.org/10.100
7/s10856-019-6279-x
202. Ni J, Ling H, Zhang S, Wang Z, Peng Z, Benyshek C et al (2019)
Three-dimensional printing of metals for biomedical applications.
Mater Today Biol 3:100024. https://doi.org/10.1016/j.mtbio.201
9.100024
203. Pati F, Jang J, Ha DH, Kim SW, Rhie JW, Shim JH et al (2014)
Printing three-dimensional tissue analogues with decellularized
extracellular matrix bioink. Nat Commun 5(1):1–11. https://doi.
org/10.1038/ncomms4935
204. Grolman JM, Zhang D, Smith AM, Moore JS, Kilian KA (2015)
Rapid 3D extrusion of synthetic tumor microenvironments. Adv
Mater 27(37):5512–5517. https://doi.org/10.1002/adma.2015017
29
205. Zema L, Melocchi A, Maroni A, Gazzaniga A (2017) Three-
dimensional printing of medicinal products and the challenge of
personalized therapy. J Pharm Sci 106(7):1697–1705. https://doi.
org/10.1016/j.xphs.2017.03.021
206. Han D, Morde RS, Mariani S, La Mattina AA, Vignali E, Yang C
et al (2020) 4D printing of a bioinspired microneedle array with
backward-facing barbs for enhanced tissue adhesion. Adv Funct
Mater 30(11):1909197. https://doi.org/10.1002/adfm.201909197
207. Christensen K, Xu C, Chai W, Zhang Z, Fu J, Huang Y (2015)
Freeform inkjet printing of cellular structures with bifurcations.
Biotechnol Bioeng 112(5):1047–1055. https://doi.org/10.1002/
bit.25501
208. Mannoor MS, Jiang Z, James T, Kong YL, Malatesta KA,
Soboyejo WO et al (2013) 3D printed bionic ears. Nano Lett
13(6):2634–2639. https://doi.org/10.1021/nl4007744
209. Perera AS, Coppens M-O (2019) Re-designing materials for
biomedical applications: from biomimicry to nature-inspired
chemical engineering. Philos Trans R Soc A Math Phys Eng Sci
377(2138):20180268. https://doi.org/10.1098/rsta.2018.0268
210. Karbalaei A, Cho HJ (2018) Microfluidic devices developed for
and inspired by thermotaxis and chemotaxis. Micromachines
9(4):149. https://doi.org/10.3390/mi9040149
123