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Alizarin Red staining of MG-63 cells grown in normal culture conditions (control) for 7 days (A) or 14 days (D), or in the presence of alginate samples for 7 days (B,C) or 14 days (E,F). Images were obtained using an inverted phase-contrast microscope with a black-and-white camera attached. Dark areas correspond to Alizarin Red staining.
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Biocompatibility, biodegradability, shear tinning behavior, quick gelation and an easy crosslinking process makes alginate one of the most studied polysaccharides in the field of regenerative medicine. The main purpose of this study was to obtain tissue-like materials suitable for use in bone regeneration. In this respect, alginate and several type...
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Three-dimensional (3D) printing of scaffolds for tissue engineering applications has grown substantially in the past two decades. Unlike conventional autografts and allografts, 3D-printed scaffolds can satisfy the growing need for personalized bony reconstruction following massive craniofacial bone loss. Employing layer-by-layer manufacturing techn...
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... It is quite likely that this behavior is related to the chemical composition of the resulting nanocomposites, given that clay was added to the system and did not retain as much water as the substituted polysaccharide. Furthermore, the physical interactions between the biopolymer and the clay, involving hydrogen bonds, as well as the increase in matrix crystallinity, as revealed by XRD studies, could result in lesser molecular flexibility and may restrict hydrogel swelling, as confirmed by other researchers [25,40,55,57] . ...
... The hydrogels continue to exhibit an elastic response as a result, and the storage modulus continues to be greater than the loss modulus [61] . Other studies have demonstrated also how the addition of clay to polymeric matrices had a favorable impact on the rheological and mechanical properties of the produced nanocomposites [57,62] . ...
... The results of FTIR spectrophotometric analyses presented in Figure 5 have shown the characteristic peaks for alginate and salecan as well as changes or shifts of these specific peaks depending on the composition of the materials. Sodium alginate presented the following commonly known wavelengths: ~1017 cm -1 for the C-O-C and C-OH bonds, ~1600 cm -1 for asymmetrical stretching vibration of COOgroup, ~1420 cm -1 for symmetrical COOgroup stretching vibration, and ~2900 cm -1 for CH symmetric stretching vibration [57] . In the case of the alginate-salecan sample investigation, the FTIR curves revealed a slightly modified peak spanning around 1019 cm -1 , which was attributed to alginate-salecan chain interactions considering that salecan generally exhibits the characteristic C-OH absorption band corresponding to the glucopyranose ring from the polysaccharide structure in the mentioned area [39,68,69] . ...
The main objective of the present work was to produce three-dimensional (3D)- printable nanocomposite hydrogels based on two kinds of marine-sourced polysaccharides doped with nanoclay with potential biomedical application. First part of the research study investigated the preparation of the polysaccharide bicomponent hydrogel formulations followed by the selection of the optimal ratio of polysaccharides concentrations which ensured proper morphostructural stability of the 3D-printed constructs. Second step aimed to generate 3D scaffolds with high printing fidelity by modulating the nanoclay amount doped within the previously selected biopolymer ink. In compliance with the additive manufacturing experiments, the alginate–salecan hydrogels enriched with the highest nanofiller concentrations demonstrated the highest suitability for 3D printing process. The morphological and structural studies confirmed the ability of the nanocomposite formulations to efficiently produce porous 3D-printed constructs with improved fidelity. The morphostructural findings underlined the implication of choosing the appropriate ratio between components, as they have a considerable impact on the functionality of printing formulations and subsequent 3D-printed structures. Hence, from the obtained results, these novel hydrogel nanocomposites inks are considered valuable biomaterials with suitable features for applications in the additive manufacturing of 3D structures with precise shape for customized regenerative therapy.
... Kazemi et al. reported that addition of NHA to the scaffolds increases the stability of the filaments and decreases the ink spreading, leading broadening pore size and porosity percentages [35]. Furthermore, it has been demonstrated that composite networks are more likely to form porous structures when NC is involved [36]. According to previous findings, the required porosity and pore size for bone scaffolds is in the range of 60-90% and 100-600 µm respectively which is suitable for angiogenesis, cell migration, and bone ingrowth [10,37,38]. ...
Numerous clinical bone disorders, such as infections and bone loss from cancer or trauma, increase the need for bone regeneration. Due to the difficulty of self-repairing large bone defects, bone tissue engineering has gained popularity. In this study, polycaprolactone(PCL)-gelatin(GEL) scaffolds with varying concentrations of nanohydroxyapatite (NHA) and nanoclay (NC) particles were fabricated using 3D printing technology, and their physiochemical and biological properties were assessed. PCL has excellent mechanical properties, but its hydrophobicity and long-term degradation limit its utility in scaffold fabrication. Thus, GEL, NHA and NC have been used to improve the overall performance of the polymer such as hydrophilicity, strength, adhesiveness, biocompatibility, biodegradability, and osteoconductivity. The morphological analysis revealed 3D printed structures with rectangular interconnected pores and well-distributed nanoparticles. The highest porosity belonged to PCL-GEL/NHA-NC (30/70) at 69.49%, which may directly contributed to the increase in the compressive modulus and degradation rate. The wettability, compressive strength, water uptake rate, biodegradability, and bioactivity of PCL-GEL scaffolds improved significantly as the NC concentration increased. The behavior of the seeded MG-63 cells on the 3D printed nanocomposite scaffolds was evaluated using the MTT assay, DAPI staining, and SEM micro images. It was discovered that the inclusion of NHA and NC nanoparticles can promote cell proliferation, viability, and adherence. Through the obtained in vitro results, the fabricated 3D printed PCL-GEL/NHA scaffold with higher NC concentration can be regarded as a promising scaffold for expediting the repair of bone defects.
... The NC-incorporated Algin is enclosed into the interlayer interval of NC through hydrogen bonds. In this way, the -COO− groups of the Algin could interact with the -OH groups of NC to form hydrogen bonds [35]. ...
Today, tissue engineering strategies need the improvement of advanced hydrogels with biological and mechanical properties similar to natural cartilage for joint regeneration. In this study, an interpenetrating network (IPN) hydrogel composed of gelatin methacrylate (GelMA)/alginate (Algin)/nano-clay (NC) with self-healing ability was developed with particular consideration to balancing of the mechanical properties and biocompatibility of bioink material. Subsequently, the properties of the synthesized nanocomposite IPN, including the chemical structure, rheological behavior, physical properties (i.e. porosity and swelling), mechanical properties, biocompatibility, and self-healing performance were evaluated to investigate the potential application of the developed hydrogel for cartilage tissue engineering (CTE). The synthesized hydrogels showed highly porous structures with dissimilar pore sizes. The results revealed that the NC incorporation improved the properties of GelMA/Algin IPN, such as porosity, and mechanical strength (reached 170 ± 3.5 kPa), while the NC incorporation decreased the degradation (63.8 %) along with retaining biocompatibility. Therefore, the developed hydrogel showed a promising potential for the treatment of tissue defects in cartilage.
... X-ray diffraction (XRD, X'Pert Pro X-ray diffractometer, Phillips, Germany) and Fourier transform infrared spectroscopy (Tensor27, Bruker, Germany), operating in the wavenumber range of 4000 cm −1 -400 cm −1 , were used to characterize alginate, hybrid hydrogels and SNFs. The β-sheet content of degummed SNFs in the nanofibrillar state and after the 3D printing process was estimated using the FTIR spectra and Equation (1) [37]: ...
The main challenge of extrusion 3D bioprinting is the development of bioinks with the desired rheological and mechanical performance and biocompatibility to create complex and patient-specific scaffolds in a repeatable and accurate manner. This study aims to introduce non-synthetic bioinks based on alginate (Alg) incorporated with various concentrations of silk nanofibrils (SNF, 1, 2, and 3 wt.%) and optimize their properties for soft tissue engineering. Alg-SNF inks demonstrated a high degree of shear-thinning with reversible stress softening behavior contributing to extrusion in pre-designed shapes. In addition, our results confirmed the good interaction between SNFs and alginate matrix resulted in significantly improved mechanical and biological characteristics and controlled degradation rate. Noticeably, the addition of 2 wt.% SNF improved the compressive strength (2.2 times), tensile strength (5 times), and elastic modulus (3 times) of alginate. In addition, reinforcing 3D-printed alginate with 2 wt.% SNF resulted in increased cell viability (1.5 times) and proliferation (5.6 times) after 5 days of culturing. In summary, our study highlights the favorable rheological and mechanical performances, degradation rate, swelling, and biocompatibility of Alg-2SNF ink containing 2 wt.% SNF for extrusion-based bioprinting.
... Sodium alginate is a natural polysaccharide mainly extracted from brown algae. Alginate has excellent printability and (1) good gelation characteristics, which can cross-link with calcium ions to form a gel; (2) its printability can adjust the viscosity of the solution by changing the material ratio and temperature to meet the basic requirements of extrusion printing [18]. ...
Vascular replacement is one of the most effective tools to solve cardiovascular diseases, but due to the limitations of autologous transplantation, size mismatch, etc., the blood vessels for replacement are often in short supply. The emergence of artificial blood vessels with 3D bioprinting has been expected to solve this problem. Blood vessel prosthesis plays an important role in the field of cardiovascular medical materials. However, a small-diameter blood vessel prosthesis (diameter < 6 mm) is still unable to achieve wide clinical application. In this paper, a response surface analysis was firstly utilized to obtain the relationship between the contact angle and the gelatin/sodium alginate mixed hydrogel solution at different temperatures and mass percentages. Then, the self-developed 3D bioprinter was used to obtain the optimal printing spacing under different conditions through row spacing, printing, and verifying the relationship between the contact angle and the printing thickness. Finally, the relationship between the blood vessel wall thickness and the contact angle was obtained by biofabrication with 3D bioprinting, which can also confirm the controllability of the vascular membrane thickness molding. It lays a foundation for the following study of the small caliber blood vessel printing molding experiment.
... The properties of the obtained materials confirm their use in tissue engineering. According to the biological analysis, these authors showed that the addition of unmodified clay into the alginate polymer allows for the development of cells [125]. ...
Over the last two decades, bio-polymer fibers have attracted attention for their uses in gene therapy, tissue engineering, wound-healing, and controlled drug delivery. The most commonly used bio-polymers are bio-sourced synthetic polymers such as poly (glycolic acid), poly (lactic acid), poly (e-caprolactone), copolymers of polyglycolide and poly (3-hydroxybutyrate), and natural polymers such as chitosan, soy protein, and alginate. Among all of the bio-polymer fibers, alginate is endowed with its ease of sol–gel transformation, remarkable ion exchange properties, and acid stability. Blending alginate fibers with a wide range of other materials has certainly opened many new opportunities for applications. This paper presents an overview on the modification of alginate fibers with nano-particles, adhesive peptides, and natural or synthetic polymers, in order to enhance their properties. The application of alginate fibers in several areas such as cosmetics, sensors, drug delivery, tissue engineering, and water treatment are investigated. The first section is a brief theoretical background regarding the definition, the source, and the structure of alginate. The second part deals with the physico-chemical, structural, and biological properties of alginate bio-polymers. The third part presents the spinning techniques and the effects of the process and solution parameters on the thermo-mechanical and physico-chemical properties of alginate fibers. Then, the fourth part presents the additives used as fillers in order to improve the properties of alginate fibers. Finally, the last section covers the practical applications of alginate composite fibers.
... Thus, Coll sample presented the minimum pore size with Dmed = 132 µm while the samples with mineral clays exhibited slightly higher values starting from Dmed = 147 µm for unmodified clay sample (Coll-ClNa) to Dmed~160 to 170 µm for organomodified mineral clays containing samples [33]. These findings are in good agreement with other studies that observed greater pore sizes when clay particles are added to the biopolymer matrix [41][42][43]. ...
... Thus, Coll sample presented the minimum pore size with Dmed= 132 μm while the samples with mineral clays exhibited slightly higher values starting from Dmed= 147 μm for unmodified clay sample (Coll-ClNa) to Dmed ~160 to 170 μm for organomodified mineral clays containing samples [33]. These findings are in good agreement with other studies that observed greater pore sizes when clay particles are added to the biopolymer matrix [41][42][43]. ...
... Thus, the biological evaluation of the composites was found in good agreement with literature data, which suggested that a good biocompatibility occurs only in composites samples with a specific concentration of clay in the polymeric matrices [44]. The specific concentration refers to the recipe used in the synthesis and could range from 0.01 to 7% w/v [43]. In order to test the biocompatibility of the new collagen composites, we used the MTT assay, which is recognized as a proper method for measuring the cytotoxicity of new biomaterials [60]. ...
The fabrication of collagen-based biomaterials for skin regeneration offers various challenges for tissue engineers. The purpose of this study was to obtain a novel series of composite biomaterials based on collagen and several types of clays. In order to investigate the influence of clay type on drug release behavior, the obtained collagen-based composite materials were further loaded with gentamicin. Physiochemical and biological analyses were performed to analyze the obtained nanocomposite materials after nanoclay embedding. Infrared spectra confirmed the inclusion of clay in the collagen polymeric matrix without any denaturation of triple helical conformation. All the composite samples revealed a slight change in the 2-theta values pointing toward a homogenous distribution of clay layers inside the collagen matrix with the obtaining of mainly intercalated collagen-clay structures, according X-ray diffraction analyses. The porosity of collagen/clay composite biomaterials varied depending on clay nanoparticles sort. Thermo-mechanical analyses indicated enhanced thermal and mechanical features for collagen composites as compared with neat type II collagen matrix. Biodegradation findings were supported by swelling studies, which indicated a more crosslinked structure due additional H bonding brought on by nanoclays. The biology tests demonstrated the influence of clay type on cellular viability but also on the antimicrobial behavior of composite scaffolds. All nanocomposite samples presented a delayed gentamicin release when compared with the collagen-gentamicin sample. The obtained results highlighted the importance of clay type selection as this affects the performances of the collagen-based composites as promising biomaterials for future applications in the biomedical field.
Three-dimensional (3D) bioprinting is a promising technological approach for various applications in the biomedical field. Natural polymers, which comprise the majority of 3D printable “bioinks”, have played a crucial role in various 3D bioprinting technologies during the layered 3D manufacturing processes in the last decade. However, the polymers must be customized for printing and effector function needs in cancer, dental care, oral medicine and biosensors, cardiovascular disease, and muscle restoration. This review provides an overview of 3D bio-printed natural polymers—commonly employed in various medical fields—and their recent development.
Following the introduction of osteo-immunomodulation as a new and important strategy to enhance material osseointegration, achieving an appropriate immune response after biomaterial implantation has become a significant challenge for efficient bone repair. In this study, a nanosilicate-reinforced sodium alginate (SA) hydrogel was fabricated by introducing montmorillonite (MMT) nanoparticles. Meanwhile, an immunogenically bioactive agent, harmine (HM), was loaded and released to induce macrophage differentiation into the M2 type. The fabricated SA/MMT/HM (SMH) hydrogel exhibited improved mechanical stiffness and stability, which also efficiently promoted macrophage anti-inflammatory M2 phenotype polarization and enhanced the secretion of pro-tissue healing cytokines for inducing a favorable immunomodulatory microenvironment for the osteogenic differentiation of bone marrow stromal cells (BMSCs). Furthermore, a rat air-pouch model and a critical-size bone defect model were used and the results showed that the SMH hydrogel increased the proportion of M2 macrophages and markedly reduced local inflammation, while enhancing desirable new bone formation. Transcriptomic analysis revealed that the SMH hydrogel accelerated the M1-to-M2 transition of macrophages by inhibiting relevant inflammatory signaling pathways and activating the PI3K-AKT1 signaling pathway. Taken together, this high-intensity immunomodulatory hydrogel may be a promising biomaterial for bone regeneration and provide a valuable base and positive enlightenment for massive bone defect repair.
