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Biodegradation of hyaluronic acid derivatives by hyaluronidase
Abstract
Hyaluronic acid (salt) (HA) has been chemically modified as a biomaterial for medical applications such as controlled drug release matrices, nerve guides and wound dressings. A series of HA derivatives, which include different ester types and different degrees of esterification, have been used to investigate the stability of these materials in testicular hyaluronidase. Gel permeation chromatography and capillary viscometer have been employed to determine the size of the molecules, the former used for the water insoluble derivatives that dissolve in dimethyl sulphoxide, the latter for the water soluble samples. The preliminary experimental results indicated that the molecular weight of fully esterified hyaluronic acid (both ethyl and benzyl esters) did not decrease after treatment in the enzyme for 7 and 14 days while the water soluble partially esterified HA were degraded by the enzyme producing a sharp reduction of viscosity within minutes. These observations tend to suggest that the carboxylic groups in the beta-glucoronic acid unit are the activation centre of this enzyme and the total blockage of these groups can restrict the cleavage of beta (1-->4) glycoside bonds by this enzyme.
... The main specificity of BCDI compared to bisepoxides or DVS is the location of its reaction site on HA carboxyl moieties forming an amide bond. Since the anionic carboxyl groups play a significant role in the charge/hydrophilicity of the HA chains and their biological recognition by hyaluronidase [53], modifying COO-moieties by ester or amide functions reduces the enzymatic degradation of HA chains proportionally to the degree of modification [11,53,54]. As a result, a limited amount of this crosslinker should be employed in the manufacturing of HA gels in order not to prevent their enzymatic degradability in case of an adverse event. ...
... The main specificity of BCDI compared to bisepoxides or DVS is the location of its reaction site on HA carboxyl moieties forming an amide bond. Since the anionic carboxyl groups play a significant role in the charge/hydrophilicity of the HA chains and their biological recognition by hyaluronidase [53], modifying COO-moieties by ester or amide functions reduces the enzymatic degradation of HA chains proportionally to the degree of modification [11,53,54]. As a result, a limited amount of this crosslinker should be employed in the manufacturing of HA gels in order not to prevent their enzymatic degradability in case of an adverse event. ...
... These innovative routes for HA crosslinking pave the way to brand new HA filler materials with tunable viscoelasticity, selfhealing properties, and enhanced adhesion to surrounding tissues, potentially manufactured using greener and safer raw materials. The duration of in vivo clinical effect could be fine-tuned by modifying enzymatic recognition sites [53] or by the addition of hyaluronidase inhibitors embedded in gels [85]. A special attention is nevertheless the capacity to still allow a prompt and complete filler dissolution, if needed to resolve safety issues or correct esthetically displeasing outcomes. ...
Introduction
Hyaluronan (HA)-based soft-tissue fillers are injectable crosslinked hydrogels aimed to counteract facial skin aging signs via minimally invasive procedures. The crosslinking step is required to drastically improve HA residence time in vivo and provide the gel with specific viscoelastic properties matching the clinical indications. While HA as a raw material and HA fillers are widely studied, little is reported about crosslinkers themselves used in commercial fillers.
Areas covered
This article introduces the specifications of the ideal crosslinker in HA fillers. The properties of commercially used crosslinkers are reviewed. An up-to-date review of innovative hydrogel fabrication alternatives is conducted, and advantages and drawbacks are discussed.
Expert opinion
HA fillers are predominantly manufactured using 1,4-butanediol diglycidyl ether (BDDE) which is considered as the gold standard crosslinker worldwide due to its proven and unrivalled clinical track record of more than 20 years. Extensive studies have been published covering BDDE-crosslinked HA fillers’ chemistry, gel properties, and clinical effectiveness and safety. However, new hydrogel fabrication strategies have emerged, paving the way for innovative alternatives potentially bringing novel features to HA fillers. Nevertheless, major efforts must still be implemented to assess their safety, efficacy, stability and suitability for industrialization.
... The human body contains approximately 15 g of HA, with nearly 50% of the total body's HA content found in the skin [2]. The degradation of HA is mostly by endogenous hyaluronidases (HAase), a class of enzyme, clipping the β-(1 → 4) glycosidic bond [3]. Their potency, or enzymatic activity, is determined by turbidimetric assays, which may vary between European and American standards [4]. ...
... Although numerous functionalization pathways were developed to create HA hydrogels [7][8][9], 1,4 butanediol diglycidyl ether (BDDE) remains the gold standard for soft tissue fillers, including the TEOSYAL RHA ® collection (Teoxane SA, Geneva, Switzerland) [10]. In alkaline conditions, BDDE reacts with the hydroxyl moieties of HA to form an elastic polymer network, slowing down the degradation process without hampering gel degradation via β- (1,4) glycosidic bonds cleavage by HAase [3,[11][12][13]. ...
Minimally invasive hyaluronan (HA) tissue fillers are routinely employed to provide tissue projection and correct age-related skin depressions. HA fillers can advantageously be degraded by hyaluronidase (HAase) administration in case of adverse events. However, clear guidelines regarding the optimal dosage and mode of administration of HAase are missing, leaving a scientific gap for practitioners in their daily practice. In this study, we implemented a novel rheological procedure to rationally evaluate soft tissue filler degradability and optimize their degradation kinetics. TEOSYAL RHA ® filler degradation kinetics in contact with HAase was monitored in real-time by rheological time sweeps. Gels were shown to degrade as a function of enzymatic activity, HA concentration, and BDDE content, with a concomitant loss of their viscoelastic properties. We further demonstrated that repeated administration of small HAase doses improved HA degradation kinetics over large single doses. Mathematical analyses were developed to evaluate the degradation potential of an enzyme. Finally, we tuned the optimal time between injections and number of enzymatic units, maximizing degradation kinetics. In this study, we have established a scientific rationale for the degradation of HA fillers by multidose HAase administration that could serve as a basis for future clinical management of adverse events.
... Since it can be used to develop nanosystems with various functions and has good biocompatibility, non-toxicity, and mucoadhesiveness for increasing drug absorption and bioavailability, chitosan is frequently regarded as one of the most commonly used polysaccharides in the field of nanomedicine [50]. Chitosan-based nanomedicines often exhibit great bio-Biocompatibility [36], Biodegradability [37], No immunogenicity [38], Non-toxic [39], Strong affinity for cancer cell receptors such as CD44 [40]. ...
... Biocompatibility [36], Biodegradability [37], No immunogenicity [38], Non-toxic [39], Strong affinity for cancer cell receptors such as CD44 [40]. ...
A primary illness that accounts for a significant portion of fatalities worldwide is cancer. Among the main malignancies, lung cancer is recognised as the most chronic kind of cancer around the globe. Radiation treatment, surgery, and chemotherapy are some medical procedures used in the traditional care of lung cancer. However, these methods lack selectivity and damage nearby healthy cells. Several polysaccharide-based nanomaterials have been created to transport chemotherapeutics to reduce harmful and adverse side effects and improve response during anti-tumour reactions. To address these drawbacks, a class of naturally occurring polymers called polysaccharides have special physical, chemical, and biological characteristics. They can interact with the immune system to induce a better immunological response. Furthermore, because of the flexibility of their structures, it is possible to create multifunctional nanocomposites with excellent stability and bioavailability for the delivery of medicines to tumour tissues. This study seeks to present new views on the use of polysaccharide-based chemotherapeutics and to highlight current developments in polysaccharide-based nanomedicines for lung cancer.
... It is important to consider that when modifying HA, changes made to -COOH group can affect the behavior of the HA molecule in the body since HA receptors and hyaluronidase recognize carboxylic groups [37]. Hyaluronan functional groups (hydroxyl, carboxyl, and acetyl) can be modified chemically in two different ways: either by conjugation or cross-linking [38]. ...
Hyaluronan (HA) is a non-sulfated glycosaminoglycan that is present in a variety of body tissues and organs. Hyaluronan has a wide range of biological activities that are frequently influenced by molar mass; however, they also depend greatly on the source, purity, and kind of impurities in hyaluronan. High-molar-mass HA has anti-inflammatory, immunosuppressive, and antiangiogenic properties, while low-molar-mass HA has opposite properties. A number of chemical modifications have been performed to enhance the stability of HA and its applications in medical practice. Hyaluronan is widely applied in medicine, such as viscosupplementation, ophthalmology, otolaryngology, wound healing, cosmetics, and drug delivery. In this review, we summarized several medical applications of polymers based on the hyaluronan backbone.
... This approach takes advantage of the fact that hyaluronidase can cut HA chains, the main component of SSF, into two monosaccharide fragments of lower molecular weight which, and this is our hypothesis, should reduce the viscosity of the medium. [52] To test this hypothesis, we investigated the viscosity of SSF at varying shear rates (from 1 to 100 s −1 ) after exposing the medium to different concentrations of HyaNMs for 4 h. The results clearly show that the viscosity of SSF decreased as the HyaNM concentration was increased ( Figure 3B i). ...
Over the past decades, the development of nanoparticles (NPs) to increase the efficiency of clinical treatments has been subject of intense research. Yet, most NPs have been reported to possess low efficacy as their actuation is hindered by biological barriers. For instance, synovial fluid (SF) present in the joints is mainly composed of hyaluronic acid (HA). These viscous media pose a challenge for many applications in nanomedicine, as passive NPs tend to become trapped in complex networks, which reduces their ability to reach the target location. This problem can be addressed by using active NPs (nanomotors, NMs) that are self‐propelled by enzymatic reactions, although the development of enzyme‐powered NMs, capable of navigating these viscous environments, remains a considerable challenge. Here, the synergistic effects of two NMs troops, namely hyaluronidase NMs (HyaNMs, Troop 1) and urease NMs (UrNMs, Troop 2) are demonstrated. Troop 1 interacts with the SF by reducing its viscosity, thus allowing Troop 2 to swim more easily through the SF. Through their collective motion, Troop 2 increases the diffusion of macromolecules. These results pave the way for more widespread use of enzyme‐powered NMs, e.g., for treating joint injuries and improving therapeutic effectiveness compared with traditional methods.
... In the human body, there are special enzymes-hydrolases (class III enzymes), which catalyze hydrolytic bonds (carbonoxygen (C-O), carbon-nitrogen (C-N), carbon-carbon (C-C), phosphorus-nitrogen (P-N) bonds, etc.) and cleavage involving water. For example, hyaluronic acid (HA) is degraded by the hydrolase hyaluronidase [93]. Other polymers that undergo enzymatic hydrolysis and/or pH-sensitive hydrolysis/gelation are chitosan, gelatin, etc. [94,95]. ...
Hydrogels have many useful physicochemical properties which, in combination with their biocompatibility, suggest their application as a drug delivery system for the local and prorogated release of drugs. However, their drug-absorption capacity is limited because of the gel net’s poor adsorption of hydrophilic molecules and in particular, hydrophobic molecules. The absorption capacity of hydrogels can be increased with the incorporation of nanoparticles due to their huge surface area. In this review, composite hydrogels (physical, covalent and injectable) with included hydrophobic and hydrophilic nanoparticles are considered as suitable for use as carriers of anticancer chemotherapeutics. The main focus is given to the surface properties of the nanoparticles (hydrophilicity/hydrophobicity and surface electric charge) formed from metal and dielectric substances: metals (gold, silver), metal-oxides (iron, aluminum, titanium, zirconium), silicates (quartz) and carbon (graphene). The physicochemical properties of the nanoparticles are emphasized in order to assist researchers in choosing appropriate nanoparticles for the adsorption of drugs with hydrophilic and hydrophobic organic molecules.
... The hydrogels were sensitive to BTH-catalyzed hydrolysis although more resistant, compared to the widely used HA-BDDE-derivatives, notwithstanding the lower chemical stability. This is in line with other data on self-esterified HA and was also expected considering that self-crosslinking involves the HA carboxylate moieties that are key to BTH action and that are instead not modified in the reaction with BDDE [51]. This would also explain the hard to detect degradation of the more highly esterified samples (XHA30-100) in the presence of BTH. ...
Hyaluronan-(HA) short half-life in vivo limits its benefits in tissue repair. Self-esterified-HA is of great interest because it progressively releases HA, promoting tissue-regeneration longer than the unmodified-polymer. Here, the 1-ethyl-3-(3-diethylaminopropyl)carbodiimide(EDC)-hydroxybenzotriazole(HOBt) carboxyl-activating-system was evaluated for self-esterifying HA in the solid state. The aim was to propose an alternative to the time-consuming, conventional reaction of quaternary-ammonium-salts of HA with hydrophobic activating-systems in organic media, and to the EDC-mediated reaction, limited by by-product formation. Additionally, we aimed to obtain derivatives releasing defined molecular-weight(MW)-HA that would be valuable for tissue renewal. A 250 kDa-HA(powder/sponge) was reacted with increasing EDC/HOBt amounts. HA-modification was investigated through Size-Exclusion-Chromatography-Triple-Detector-Array-analyses, FT-IR/1H NMR and the products(XHAs) extensively characterized. Compared to conventional protocols, the set procedure is more efficient, avoids side-reactions, allows for an easier processing to diverse clinically-usable 3D-forms, leads to products gradually releasing HA under physiological conditions with the possibility to tune the MW of the biopolymer-released. Finally, the XHAs exhibit sound stability to Bovine-Testicular-Hyaluronidase, hydration/mechanical properties suitable for wound-dressings, with improvements over available matrices, and prompt in vitro wound-regeneration, comparably to linear-HA. To the best of our knowledge, the procedure is the first valid alternative to conventional protocols for HA self-esterification with advances in the process itself and in product performance.
... Thus, modification in carboxyl group results in alteration of HA's biological behavior 4 . Zhong, et al. 162 concluded that increasing degree of HA modification led to delay in enzymatic degradation of HA derivatives. ...
Hyaluronic acid (HA), a natural biodegradable and biocompatible polymer fabricated in the human body has attracted considerable attention from scientists in recent years. HA is a nonsulfated glycosaminoglycan and a major component of the extracellular matrix. The unique properties of HA and its wide range of molecular weight have resulted in this polymer being formulated and used in diverse biomedical applications such as drug delivery systems. HA can play an essential role as a carrier for delivery and controlled release of different bio and chemical molecules such as proteins, nucleic acids, and anti-tumor drugs in various routes. It can also be used as a targeting agent in modified delivery systems as its main receptor (CD44) is highly expressed in many types of cancers. Many research studies have exhibited the potential of HA in further targeted chemotherapy, gen therapy, and immunotherapy applications.this chapter discusses the main characteristics of HA and its distinctive applications drug/gen delivery and imaging system.
... Since the Gel and Peptide groups were acellular, bone regeneration in the trabecular space would have had to be produced by native cells that migrated into the hydrogel. The migration of native cells into the trabecular space may have been aided by the presence of hyaluronidase, an enzyme that breaks down hyaluronic acid by cleaving its glycosidic bonds, in the femoral shaft (Zhong et al., 1994). Although DWIVA-functionalized hydrogels were exposed to hyaluronidase in vivo, the bioactivity of the hydrogel was preserved as shown by improved trabecular bone growth in the Peptide group. ...
Osteoporosis is a disease characterized by a decrease in bone mineral density, thereby increasing the risk of sustaining a fragility fracture. Most medical therapies are systemic and do not restore bone in areas of need, leading to undesirable side effects. Injectable hydrogels can locally deliver therapeutics with spatial precision, and this study reports the development of an injectable hydrogel containing a peptide mimic of bone morphogenetic protein-2 (BMP-2). To create injectable hydrogels, hyaluronic acid was modified with norbornene (HANor) or tetrazine (HATet) which upon mixing click into covalently crosslinked Nor-Tet hydrogels. By modifying HANor macromers with methacrylates (Me), thiolated BMP-2 mimetic peptides were immobilized to HANor via a Michael addition reaction, and coupling was confirmed with 1H NMR spectroscopy. BMP-2 peptides presented in soluble and immobilized form increased alkaline phosphatase (ALP) expression in MSCs cultured on 2D and encapsulated in 3D Nor-Tet hydrogels. Injection of bioactive Nor-Tet hydrogels into hollow intramedullary canals of Lewis rat femurs showed a local increase in trabecular bone density as determined by micro-CT imaging. The presented work shows that injectable hydrogels with immobilized BMP-2 peptides are a promising biomaterial for the local regeneration of bone tissue and for the potential local treatment of osteoporosis.
... HA is proven to be highly water-soluble [15,68,69]. This signifies that HA should act for a short period of time because of a quick dissolving process, although in our study we revealed changes on day 6. ...
Introduction:
The effective induction of angiogenesis is directly related to the success of bone-substitute materials (BSM) for maxillofacial osseous regeneration. Therefore, the addition of pro-angiogenic properties to a commercially available bovine bone-substitute material in combination with hyaluronic acid (BSM+) was compared to the same bone-substitute material without hyaluronic acid (BSM) in an in-vivo model.
Materials and methods:
BSM+ and BSM were incubated for six days on the chorioallantoic membrane (CAM) of fertilized chicken eggs. Microscopically, the number of vessels and branching points, the vessel area and vessel length were evaluated. Subsequently, the total vessel area and brightness integration were assessed after immunohistochemical staining (H&E, alphaSMA).
Results:
In the BSM+ group, a significantly higher number of vessels (p < 0.001), branching points (p = 0.001), total vessel area (p < 0.001) as well as vessel length (p = 0.001) were found in comparison to the BSM group without hyaluronic acid. Immunohistochemically, a significantly increased total vessel area (p < 0.001 for H&E, p = 0.037 for alphaSMA) and brightness integration (p = 0.047) for BSM+ in comparison to the native material were seen.
Conclusions:
The combination of a xenogenic bone-substitute material with hyaluronic acid significantly induced angiogenesis in vivo. This might lead to a faster integration and an improved healing in clinical situations.
... HAase inhibitors can be used to reduce the activity of HAase to preserve the properties of HA-based biomaterials. [42][43][44] For example, Kim et al. recently reported the retarded degradation of cross-linked HA hydrogels in vivo by incorporating HAase inhibitor (i.e., quercetin) into them. 45 Hence, we hypothesized that the release of HI in the vicinity of PPy/HA could reduce the hydrolytic action of HAase against the HA dopant, offering persistent resistance to cell binding and preserving electrochemical functions. ...
Conductive polymers, including polypyrrole (PPy), have garnered much attention as bioelectrodes because of their high conductivity, low interfacial resistance, environmental stability, and biocompatibility. In particular, the introduction of high-molecular weight hyaluronic acid (HA) into PPy enables the fabrication of biomimetic and biocompatible electrodes (i.e., PPy/HA) characterized by low biofouling. However, as HA is readily degraded by enzymes (i.e., hyaluronidase (HAase)) in a biological milieu, PPy/HA substantially loses its original properties, including resistance to cell adhesion and electrical activity. We found that HAase treatment of PPy/HA substantially degraded the HA moieties in PPy/HA, resulting in increased water contact angles, increased impedance, and conversion of non-cell adhesive to cell adhesive surfaces. Hence, it is desirable to mitigate HA degradation to achieve persistent performance of PPy/HA electrodes. Accordingly, we incorporated glycyrrhizin as an HAase inhibitor (HI) into PPy/HA electrodes. HI-incorporated PPy/HA (PPy/HA/HI) successfully prevented the degradation of the HA moiety and non-specific cell adhesion on the electrodes, in the presence of HAase (2.5 U mL-1), without cytotoxicity. These excellent properties allowed for maintenance of the electrical sensitivity of PPy/HA during cell culture with HAase. Altogether, biomimetic PPy/HA, which is resistant to degradation by HAase, may serve as an effective platform for the development of reliable and biocompatible bioelectrodes.
... Hyaluronic acid (HA) is a non-sulfated glycosaminoglycan found in nearly all connective tissues and cartilage [116]. This linear molecule consists of repeating disaccharide units of d-glucuronic acid and N-acetyl-d-glucosamine moieties linked with alternating β-1,3 and β-1,4 glycosidic segments [117]. The three major functional groups primarily control the chemical activity of HA: glucuronic carboxylic acid, an N-acetyl group, and a secondary hydroxyl group [72]. ...
The development of appropriate bioinks is a complex task, dependent on the mechanical and biochemical requirements of the final construct and the type of printer used for fabrication. The two most common tissue printers are micro-extrusion and digital light projection printers. Here we briefly discuss the required characteristics of a bioink for each of these printing processes. However, physical printing is only a short window in the lifespan of a printed construct-the system must support and facilitate cellular development after it is printed. To that end, we provide a broad overview of some of the biological molecules currently used as bioinks. Each molecule has advantages for specific tissues/cells, and potential disadvantages are discussed, along with examples of their current use in the field. Notably, it is stressed that active researchers are trending towards the use of composite bioinks. Utilizing the strengths from multiple materials is highlighted as a key component of bioink development.
... However, HA is unstable and prone to degradation by hydrolytic or enzymatic reactions in vivo (Zhong et al. 1994), leading to its short-term efficacy (<6 months) and the need of repeated injections (Altman et al. 2018). Other polysaccharides have recently been studied as longer-lasting alternatives. ...
... Interestingly, HA-nimesulide conjugates revealed different activities than free nimesulide in the inhibition of pro-inflammatory cytokines ( Figure 8B,C), indicating the possibility of different mechanisms in the HAnimesulide groups. Moreover, it is reported that the degradation of HA by hyaluronidases can give rise to approximately 20 kDa cleaved-products, such as disaccharide units and smaller oligosaccharides, and the degraded HA-drug products might improve the pharmacological activities [69,70]. Therefore, we speculated that the mechanisms of action of HA-nimesulide may be different from those of nimesulide. ...
Dry eye syndrome (DES) is a common ocular disease worldwide. Currently, anti-inflammatory agents and immunosuppressive drugs, such as cyclosporine A, have been widely used to treat this chronic condition. However, the multifactorial etiology of DES, poor tolerance, low bioavailability, and prolonged treatment to response time have limited their usage. In this study, nimesulide, a cyclooxygenase (COX)-2 selective inhibitor, was conjugated with hyaluronic acid (HA), and the HA-nimesulide conjugates were expected to increase the solubility and biocompatibility for alleviating the DES in the benzalkonium chloride (BAC)-induced goblet cell-loss dry eye model. The therapeutic efficacy of HA-nimesulide was assessed using fluorescein staining, goblet cell density by conjunctival impression cytology, and histology and immunohistochemistry of corneal tissues. Compared to commercial artificial tears and Restasis®, the HA-nimesulide conjugates could promote goblet cell recovery and enhance the regeneration of the corneal epithelium. Importantly, immunofluorescent staining studies demonstrated that the HA-nimesulide conjugates could decrease the number of infiltrating CD11b-positive cells after two weeks of topical application. In the anti-inflammatory test, the HA-nimesulide conjugates could inhibit the production of pro-inflammatory cytokines and prostaglandin E2 (PGE2) in the lipopolysaccharide (LPS)-stimulated Raw 264.7 cell model. In conclusion, we demonstrated that HA-nimesulide conjugates had anti-inflammatory activity, and promoted goblet cell recovery and corneal epithelium regeneration when used as topical eye drops; accordingly, the HA-nimesulide conjugates could potentially be effective for the treatment of DES.
... In vitro, Si-HA gels were rapidly degraded by hyaluronidases, which specifically cleave β,1-4 bonds of the polysaccharide. 33 On the contrary, Si-HPMC gels were not resorbed by the enzyme, which was expected as cellulosic derivatives are only sensitive to cellulases. In vivo, Si-HA was partially degraded and infiltrated by macrophages, while Si-HPMC was found to be stable after 21 d. ...
Biphasic calcium phosphate (BCP) granules are osteoconductive biomaterials used in clinics to favor bone reconstruction. Yet, poor cohesivity, injectability and mechanical properties restrain their use as bone fillers. In this study, we incorporated BCP granules into in situ forming silanized hyaluronic acid (Si-HA) and hydroxypropylmethylcellulose (Si-HPMC) hydrogels. Hydrogel composites were shown to be easily injectable (F < 30 N), with fast hardening properties (<5 min), and similar mechanical properties (E ∼ 60 kPa). In vivo, both hydrogels were well tolerated by the host, but showed different biodegradability with Si-HA gels being partially degraded after 21d, while Si-HPMC gels remained stable. Both composites were easily injected into critical size rabbit defects and remained cohesive. After 4 weeks, Si-HPMC/BCP led to poor bone healing due to a lack of degradation. Conversely, Si-HA/BCP composites were fully degraded and beneficially influenced bone regeneration by increasing the space available for bone ingrowth, and by accelerating BCP granules turnover. Our study demonstrates that the degradation rate is key to control bone regeneration and that Si-HA/BCP composites are promising biomaterials to regenerate bone defects.
... Despite HA has been successfully commercialized, however, its short half-life hinders its clinical application (Zhong et al., 1994). To overcome the problems with HA degradation, an appealing strategy is to modify or cross-link HA to prolong the half-life of HA. ...
Owing to its outstanding water-retention ability, viscoelasticity, biocompatibility and non-immunogenicity, Hyaluronic acid (HA), a natural linear polymer alternating linked by D-glucuronic acid and N-acetylglucosamine, has been widely employed in cosmetic, medical and clinical applications. With the development of synthetic biology and bioprocessing optimization, HA production via microbial fermentation is an economical and sustainable alternative over traditional animal extraction methods. Indeed, recently Streptococci and other recombinant systems for HA synthesis has received increasing interests due to its technical advantages. This review summarizes the production of HA by microorganisms and demonstrates its synthesis mechanism, focusing on the current status in various production systems, as well as common synthetic biology strategies include driving more carbon flux into HA biosynthesis and regulating the molecular weight (MW), and finally discusses the major challenges and prospects.
... HA controls degraded quickly in the presence of hyaluronidase (Figure 7). This may be partly due to the bulk erosion arising from the highly hydrophilic character of HA [60] and partly due to the presence of hyaluronidase [61]. As the collagen is added to the HA network, degradation resistance towards hyaluronidase increases considerably as seen for S-1 and S-2. ...
In addition to biocompatibility, an ideal scaffold for the regeneration of valvular tissue
should also replicate the natural heart valve extracellular matrix (ECM) in terms of biomechanical
properties and structural stability. In our previous paper, we demonstrated the development of
collagen type I and hyaluronic acid (HA)-based scaffolds with interlaced microstructure. Such
hybrid scaffolds were found to be compatible with cardiosphere-derived cells (CDCs) to potentially
regenerate the diseased aortic heart valve. This paper focused on the quantification of the effect
of crosslinking density on the mechanical properties under dry and wet conditions as well as
degradation resistance. Elastic moduli increased with increasing crosslinking densities, in the
dry and wet state, for parent networks, whereas those of interlaced scaffolds were higher than
either network alone. Compressive and storage moduli ranged from 35 ± 5 to 95 ± 5 kPa and
16 ± 2 kPa to 113 ± 6 kPa, respectively, in the dry state. Storage moduli, in the dry state, matched and
exceeded those of human aortic valve leaflets (HAVL). Similarly, degradation resistance increased
with increasing the crosslinking densities for collagen-only and HA-only scaffolds. Interlaced
scaffolds showed partial degradation in the presence of either collagenase or hyaluronidase as
compared to when exposed to both enzymes together. These results agree with our previous
findings that interlaced scaffolds were composed of independent collagen and HA networks without
crosslinking between them. Thus, collagen/HA interlaced scaffolds have the potential to fill in the
niche for designing an ideal tissue engineered heart valve (TEHV)
... It may be hypothesized that the smaller grain size of the TCP particles used in the putty material may have a beneficial effect on graft shrinkage due to these particles being packed in a more dense fashion after introducing the graft material into the sinus floor [36]. Also the bond between the hyaluronic acid and the TCP particles and the resulting increase in viscoelasticity may contribute to reducing shrinkage during the period, over which resorption of the hyaluronic acid takes place, which can vary from days to weeks [16,17,[37][38][39]. Which of these factors may have a greater impact on preventing graft shrinkage needs to be elucidated in future studies. ...
This study examines the effect of a hyaluronic acid (HyAc) containing tricalcium phosphate putty scaffold material (TCP-P) and of a particulate tricalcium phosphate (TCP-G) graft on bone formation, volume stability and osteogenic marker expression in biopsies sampled 6 months after bilateral sinus floor augmentation (SFA) in 7 patients applying a split-mouth design. Biopsies were processed for immunohistochemical analysis of resin embedded sections. Sections were stained for collagen type I (Col I), alkaline phosphatase (ALP), osteocalcin (OC) and bone sialoprotein (BSP). Furthermore, the bone area and particle area fraction were determined histomorphometrically. Cone-beam CT data recorded after SFA and 6 month later were used for calculating the graft volume at these two time points. TCP-P displayed more advantageous surgical handling properties and a significantly greater bone area fraction and smaller particle area fraction. This was accompanied by significantly greater expression of Col I and BSP and in osteoblasts and osteoid and a less pronounced reduction in grafting volume with TCP-P. SFA using both types of materials resulted in formation of sufficient bone volume for facilitating stable dental implant placement with all dental implants having been in function without any complications for 6 years. Since TCP-P displayed superior surgical handling properties and greater bone formation than TCP-G, without the Hyac hydrogel matrix having any adverse effect on bone formation or graft volume stability, TCP-P can be regarded as excellent grafting material for SFA in a clinical setting.
... (6) Mix the test solution with the substrate solution at the time of t 1 ¼ 0. (7) Record the flow time t x of the test solution and substrate solution mixture several times during a period of $20 min (Hoechstetter, 2005;Stern & Jedrzejas, 2006;Zhong et al., 1994). (8) Calculate the viscosity ratio from the following formula: ...
Honey bees have a sting which allows them to inject venomous substances into the body of an opponent or attacker. As the sting originates from a modified ovipositor, it only occurs in the female insect, and this is a defining feature of the bee species that belong to a subclade of the Hymenoptera called Aculeata. There is considerable interest in bee venom research, primarily because of an important subset of the human population who will develop a sometimes life threatening allergic response after a bee sting. However, the use of honey bee venom goes much further, with alleged healing properties in ancient therapies and recent research. The present paper aims to standardize selected methods for honey bee venom research. It covers different methods of venom collection, characterization and storage. Much attention was also addressed to the determination of the biological activity of the venom and its use in the context of biomedical research, more specifically venom allergy. Finally, the procedure for the assignment of new venom allergens has been presented.
... Polymer degradation is an important consideration in the production and use of implantable and other medical devices and the majority of biodegradable polymers have been designed to have hydrolytically unstable bonds in the polymer backbone (in t Veld et al., 1993, Zhong et al., 1994. The choice of material is dependent on its function; it has to remain in-situ long enough to allow healing to take place, but consideration has to also be given to the fact that it will gradually lose its strength and produce breakdown products as biodégradation takes place (Ali et al., 1993, Golomb et al., 1993. ...
Hormonal stimulation of osteoblasts can provide better focal integration of orthopaedic implants. In this study both direct and indirect actions of growth hormone on primary human osteoblasts have been demonstrated. Growth hormone significantly increased cell proliferation and alkaline phosphatase activity and stimulated the synthesis of Insulin-like Growth Factor-I and the release of Insulin Growth Factor-binding protein 3. A drug delivery system releasing biologically active growth hormone targeted to osteoblasts could be used to improve tissue repair in orthopaedics. Two biomaterials have been successfully developed for this novel application. The first is based on natural biodegradable, biocompatible gelatin, in the form of microspheres, where the amount of growth hormone released was significantly increased following ultrasound treatment. The second, a non-degradable polymer based on polyethylmethacrylate and tetrahydrofurfurylmethacrylate (PEM/THFMA) showed an initial rapid release followed by a prolonged sustained release of growth hormone. The preparation method used, significantly affected the amount of growth hormone released. Varying the ratio of PEMA/HFMA and gelling it with hydroxyethylmethacrylate changed the profiles and increased the amount of growth hormone released, exposure to various temperatures did not affect the amount or bioactivity of the GH released. The initial rapid release of growth hormone locally from both systems is desirable post- operatively to stimulate osteogenic cells at the polymer interface and accelerate repair during the critical early wound healing period, whilst the subsequent slow release would enhance osteoid deposition and bone mineral formation. Both systems have advantages, the choice is dependent on the intended site of use. The microspheres are biodegradable and the GH released can be increased in a physiological manner depending on clinical requirements. The PEM/THFMA can be used where stability is required and can absorb tissue fluids and growth factors from the bone matrix, marrow and synovial fluid, thereby creating an optimal environment for rapid bone remodelling. This study has demonstrated a level of control for GH delivery in both systems and has confirmed that targeted osteoblasts respond to GH. Numerous clinical applications could benefit from these controlled systems, for example, enhancing the fixation of total joint prostheses, bone defects in non-union fractures, and in pathological conditions where local growth promoting effects would be beneficial.
... Hyaluronic acid is a linear nonsulfated glycosaminoglycan that is ubiquitous in almost all connective tissues and a major ECM component of cartilage. 97 It is comprised of repeating disaccharide units of d-glucuronic acid and N-acetyl-d-glucosamine moieties linked by alternating β-1,4 and β-1,3 glycosidic linkages 98 Hyaluronic acid is widely used in tissue engineering due to its excellent biocompatibility and ability to form flexible hydrogels. 99 One of the early applications of HA in the medical field is in eye surgery procedures, such as cataract extraction. ...
... 40% of the weight remained, the mechanical integrity of the click-hydrogels was stable enough to allow for their handling. This behaviour is in good agreement with the fact that the activation center of HA enzymatic biodegradation is found in the carboxylic acid groups in the 7-glucoronic acid units, 53 which were being blocked as a consequence of the functionalization of HA with the thiolcontaining group via EDC coupling. Such biodegradation rate is anticipated to allow the click-hydrogels to degrade while new tissue is forming. ...
Hydrogels based on hyaluronic acid (HA) exhibit great potential as tissue engineering (TE) scaffolds for cartilage regeneration as a consequence of their unique biological features. Herein, we examine how the advantages of two natural polymers (i.e. HA and alginate) are combined with the efficiency and rapid nature of the thiol-yne click chemistry reaction to obtain biocompatible matrices with tailored properties. Our injectable click-hydrogels revealed excellent mechanical performance, long-term stability, high cytocompatibility and adequate stiffness for the targeted application. This simple approach yielded HA hydrogels with characteristics that make them suitable for applications as 3D scaffolds to support and promote chondrogenesis.
... To the best of our knowledge, only one study has thus far been reported that describes the preparation and properties of HA modified with β-CD via a triazole linkage [28]. However, in this case, the cyclodextrin units were grafted onto carboxylate functional groups, which are believed to play an important role in the recognition of HA by cells [29,30]. The aim of this work was to examine whether the natural hyaluronan, which was conveniently modified with β-cyclodextrin units via the primary hydroxyl groups of HA, can form supramolecular networks with two-and three-site adamantane-based guest motifs (for structures, see Figure 1) in reversible manner. ...
A new hyaluronan derivative modified with β-cyclodextrin units (CD-HA) was prepared via the click reaction between propargylated hyaluronan and monoazido-cyclodextrin (CD) to achieve a degree of substitution of 4%. The modified hyaluronan was characterized by 1H-nuclear magnetic resonance spectroscopy (NMR) and size exclusion chromatography. Subsequent 1H-NMR and isothermal calorimetric titration experiments revealed that the CD units on CD-HA can form virtual 1:1, 1:2, and 1:3 complexes with one-, two-, and three-site adamantane-based guests, respectively. These results imply that the CD-HA chains used the multitopic guests to form a supramolecular cross-linked network. The free CD-HA polymer was readily restored by the addition of a competing macrocycle, which entrapped the cross-linking guests. Thus, we demonstrated that the new CD-HA polymer is a promising component for the construction of chemical stimuli-responsive supramolecular architectures.
... However, an increase in hydrophobicity by conjugation decreased the HA solubility, which affects the biological activities of HA, for example, CD44 binding. [146,147] Tethering pyrogallol analogs onto HA backbones prevents the enzymatic degradation of HA hydrogels. The Kurisawa group developed EGCG-conjugated HA (HA-EGCG containing dimer-type EGCGs) hydrogels with hyaluronidase resistance (Figure 14A). ...
Pyrogallol‐containing molecules are ubiquitous in the plant kingdom. The chemical synthesis of these molecules remains challenging. Thus, they are obtained via purification from heterogeneous mixtures of plant extracts. Previous studies have focused on their biological roles, such as antioxidants. Additionally, the molecules are used as ink colorants and in tanning processes for leather. Recently, many disciplines have paid attention to adhesiveness of pyrogallol‐containing molecules, including the control of interface properties in energy storage/generation and medical devices, as well as the changes in wettability related to membrane technologies. In particular, pyrogallol‐containing molecules act as “molecular glues,” binding to virtually all biomacromolecules, for example, DNA/RNA, soluble proteins, insoluble extracellular matrices, and peptides. Furthermore, the cohesion of pyrogallol by forming pyrogallol‐to‐pyrogallol covalent bonds is useful for the preparation of bulk hydrogels and thin films. The content of this review focuses on interactions with biomacromolecules used as molecular glues, used as modifiers in material‐independent surface chemistry, and applied as chemical moieties to form covalent linkages to fabricate hydrogels and related biomaterials. Future perspectives include the development of new pyrogallol‐containing materials, the understanding of chirality in adhesion, and the improvement of the mechanical stability for applications in various biomedical, energy, and industrial devices.
... In Fig. 9, the degradation kinetics of the synthesized MeHA hydrogels in a PBS-hyaluronidase solution (250 U per mL PBS) at 37°C are shown. Hydrogel degradation was attributed to the breakage of the HA backbone and, more specifically, to the cleavage of internal linkages of N-acetyl-D-glucosamine by hyaluronidase [44,46,47]. In all cases, the hyaluronidase induced hydrogel degradation followed a first-order kinetic model [43]. ...
Injectable methacrylated hyaluronic acid (MeHA) hydrogels for the repair of cartilage lesions were synthesized using two different crosslinking methods, namely, a redox initiation system (i.e., ammonium persulfate, APS, and N,N,N,N′-tetramethylenediamine, TEMED) and a matrix metalloproteinase 7 (MMP7)-degradable peptide. The effects of molecular weight of HA, degree of methacrylation (DM) or/and biofunctionalization of MeHA (i.e., with a chondroitin sulfate (CS) binding peptide) on the end-use properties of synthesized hydrogels were experimentally investigated. It was found that the storage modulus (G′) of the hydrogels synthesized, using a redox initiation system (i.e., APS and TEMED), increased as the DM of MeHA or/and the molecular weight of HA increased, resulting in the formation of more rigid hydrogels exhibiting a lower degree of swelling and a slower hydrogel degradation rate. The functionalization of MeHA with a CS binding peptide resulted in an increase of the gelation onset time as well as in a decrease of the hydrogel crosslinking density (i.e., resulting in the formation of softer hydrogels). Moreover, it was found that as the concentration of the peptide crosslinker increased the hydrogel onset time decreased as well as the degradation rate of the synthesized hydrogels while their storage modulus (G′) increased. Finally, it was found that when the MeHA crosslinking reaction was carried out in a cell growth medium the storage modulus of the hydrogel increased to a value that favored the differentiation of human mesenchymal stem cells (hMSCs) to chondrocytes.
Noninflammatory nodules arising from the injection of biostimulatory fillers persist as an unwanted complication. Pathologically, noninflammatory nodules may arise from superficial injection, accidental boluses, or incorrect concentration of microparticles contained within the filler. This case report introduces a method for reversing calcium hydroxylapatite (CaHA) using focused mechanical vibration. An in situ hyperdilution was created by injecting saline into the nodule core to prepare it for resuspension. Topical microneedling was subsequently applied to generate vibrations, aiming to disperse the accumulated CaHA particles. The outcome demonstrated a significant reduction in the size and visibility of the nodule. This combined saline-microneedling approach offers a potential noninvasive, nonpharmacologic solution for managing superficial CaHA nodules.
Level of Evidence: 5
Injectable dermal fillers, which are used for various plastic surgery purposes, are experiencing explosive market growth due to increasing interest in appearance management. Hyaluronic acid (HA) hydrogels have been considered an ideal material for fillers due to their high-water retention, biodegradability, and biocompatibility. However, their application is limited by shortcomings in durability and persistence caused by rapid enzymatic degradation. Therefore, in this study, we introduce acetylated hyaluronic acid-divinyl sulfone (AcHA-DVS) hydrogels for a novel approach for improving the physical properties and gel retention time of HA. The AcHA-DVS hydrogels showed significant advantages in terms of longevity and performance as dermal fillers compared to HA-DVS hydrogels. These results suggest that our new AcHA-DVS hydrogel is a promising biomaterial as an injectable filler or scaffold for tissue engineering.
Polysaccharides, polynucleotides, and polypeptides are basic natural polymers. They have
various applications based on their properties. This review mostly discusses the application of natural
polymers as emulsion stabilizers. Natural emulsion stabilizers are polymers of amino acid, nucleic
acid, carbohydrate, etc., which are derived from microorganisms, bacteria, and other organic materials.
Plant and animal proteins are basic sources of natural emulsion stabilizers. Pea protein-maltodextrin
and lentil protein feature entrapment capacity up to 88%, (1–10% concentrated), zein proteins feature
74–89% entrapment efficiency, soy proteins in various concentrations increase dissolution, retention,
and stability to the emulsion and whey proteins, egg proteins, and proteins from all other animals
are applicable in membrane formation and encapsulation to stabilize emulsion/nanoemulsion. In
pharmaceutical industries, phospholipids, phosphatidyl choline (PC), phosphatidyl ethanol-amine
(PE), and phosphatidyl glycerol (PG)-based stabilizers are very effective as emulsion stabilizers.
Lecithin (a combination of phospholipids) is used in the cosmetics and food industries. Various
factors such as temperature, pH, droplets size, etc. destabilize the emulsion. Therefore, the emulsion
stabilizers are used to stabilize, preserve and safely deliver the formulated drugs, also as a preservative
in food and stabilizer in cosmetic products. Natural emulsion stabilizers offer great advantages
because they are naturally degradable, ecologically effective, non-toxic, easily available in nature,
non-carcinogenic, and not harmful to health.
The limited self-repair capacity of articular cartilage has motivated the development of stem cell therapy based on artificial scaffolds that mimic the extracellular matrix (ECM) of cartilage tissue. In view of the specificity of articular cartilage, desirable tissue adhesiveness and stable mechanical properties under cyclic mechanical loads are critical for cartilage scaffolds. Herein, we developed an injectable and degradable organic-inorganic hybrid hydrogel as a cartilage scaffold based on polyhedral oligomeric silsesquioxane (POSS)-cored polyphosphate and polysaccharide. Specifically, acrylated 8-arm star-shaped POSS-poly(ethyl ethylene phosphate) (POSS-8PEEP-AC) was synthesized and cross-linked with thiolated hyaluronic acid (HA-SH) to form a degradable POSS-PEEP/HA hydrogel. Incorporation of POSS in the hydrogel increased the mechanical properties. The POSS-PEEP/HA hydrogel showed enzymatic biodegradability and favorable biocompatibility, supporting the growth and differentiation of human mesenchymal stem cells (hMSCs). The chondrogenic differentiation of encapsulated hMSCs was promoted by loading transforming growth factor-β3 (TGF-β3) in the hydrogel. In addition, the injectable POSS-PEEP/HA hydrogel was capable of adhering to rat cartilage tissue and resisting cyclic compression. Furthermore, in vivo results revealed that the transplanted hMSCs encapsulated in the POSS-PEEP/HA hydrogel scaffold significantly improved cartilage regeneration in rats, while the conjugation of TGF-β3 achieved a better therapeutic effect. The present work demonstrated the potential of the injectable, biodegradable, and mechanically enhanced POSS-PEEP/HA hybrid hydrogel as a scaffold biomaterial for cartilage regeneration.
Injectable dermal fillers, which are used for various plastic surgery purposes, are experiencing explosive growth in the market due to increasing interest in appearance management. Hyaluronic acid (HA) hydrogels have been considered an ideal material for fillers due to their high-water retention, biodegradability, and biocompatibility. However, their application is limited by shortcomings in durability and persistence caused by rapid enzymatic degradation. Therefore, in this study, we introduce acetylated hyaluronic acid-divinyl sulfone (AcHA-DVS) hydrogels for novel approach to improving the physical properties and gel retention time of HA. The AcHA-DVS hydrogels showed significant advantages in terms of longevity and performance as dermal fillers compared to HA-DVS hydrogels. These results suggest that our new AcHA-DVS hydrogel is a promising biomaterial for use as an injectable filler or scaffold of tissue engineering.
Fibrous scaffolds are commonly used as scaffolds in tissue engineering as they have remarkably high surface-area-to-volume ratio. Surface modification of fibrous constructs by employing innovative post-processing techniques such as chemical modifications, using coating gradients or active cues, avenues for tuning cellular respones. Most of the commercial polymers/unmodified polymeric scaffolds contribute little to generate biological activity. The below described methods offer plethora of chances by altering the complexity of fibers for efficient scale-up that would be relevant for industrial applications. It is also to be taken into consideration that while modifying the surface of these fibers, the mechanical properties of the materials are to be retained as such. In this chapter, we have discussed about the various modification chemistry and techniques to improve biological activity of the fibrous scaffolds.KeywordsChemical treatmentFibersHydrogel coatingPlasma treatmentSurface modification
Microneedles have the clinical advantage of being able to deliver complex drugs across the skin in a convenient and comfortable manner yet haven't successfully transitioned to medical practice. Diabetes mellitus is a complicated disease, which is commonly treated with multiple daily insulin injections, contributing to poor treatment adherence. Firstly, this review determines the clinical prospect of microneedles, alongside considerations that ought to be addressed before microneedle technology can be translated from bench to bedside. Thereafter, we use diabetes as a case study to consider how microneedle-based-technology may be successfully harnessed. Here, publications referring to insulin microneedles were evaluated to understand whether insertion efficiency, angle of insertion, successful dose delivery, dose adjustability, material biocompatibility and therapeutic stability are being addressed in early stage research. Moreover, over 3,000 patents from 1970-2019 were reviewed with the search term '"microneedle" AND "insulin"' to understand the current status of the field. In conclusion, the reporting of early stage microneedle research demonstrated a lack of consistency relating to the translational factors addressed. Additionally, a more rational design, based on a patient-centred approach is required before microneedle-based delivery systems can be used to revolutionise the lives of people living with diabetes following regulatory approval.
Background
Intrinsic aging promotes wrinkles formation by an imbalance between matrix synthesis/degradation in favor of degradation. This is accelerated by the exposome leading to overproduction of protease and fewer remodeling.
Objective
Protecting the integrity of extracellular matrix appears as the most efficient anti-aging solution. We developed a grafted HA specifically designed to get anti-aging property due to a specific molecular weight and acetylation degree.
Methods
A transcriptomic analysis was performed on fibroblasts, followed by a measurement of MMP secretion and subsequent effect on collagen degradation. MMP expression in skin explants concerned by chronobiological and extrinsic aging was analyzed by immunostaining. A clinical study was conducted on volunteers presenting wrinkles on face to evaluate flash reduction of wrinkles after 6 h of application by profilometry and anti-aging efficacy after 2 months by VISIA® CR2.3.
Results
Transcriptomic analysis evidenced an inhibition of MMP gene expression with acetylated HA, confirmed by an inhibition of MMPs release by fibroblasts, and a protection of type I collagen against degradation. We confirmed the reduction of MMPs in mature skin and in skin explants exposed to UV and urban dust. We demonstrated during clinical studies the flash reduction effect of acetylated HA on crow's feet wrinkles and a filling of nasogenian areas 6 h after application, and a wrinkles number reduction on nasogenian area up to 2 months of application.
Conclusion
We developed a new grafted HA owing protective properties against ECM degradation induced by chronobiological and extrinsic aging, leading to a significant and efficient anti-wrinkles effect.
Bone is dynamic tissues have structural and functional complexity with varying mechanical strength as of skeletal, craniofacial maxillary position. Despite surgery, allograft, advanced therapy, treatment of critical defects, deformities and functional restoration of bone are still challenging. BTE provides the hope, which could resolve the surgical challenges by developing the artificial functionalized bone. Use of biodegradable polymers in BTE provides variable required mechanical properties, porosity, and surface microenvironment for cellular adhesion, osteoblast proliferation and differentiation. Non-antigenic, immunomodulatory, vascularization, cytocompatibility, adjustable degradation kinetics, hydrolytic/enzymatic degradation and release of biocompatible metabolites are the main characteristics that enable biodegradable polymers for making 3D-scaffold for BTE. In the above line, this article illustrates the different biodegradable polymers that useful for the bone microenvironment and for the repair bone tissues.
Biopolymers and Their Industrial Applications: From Plant, Animal, and Marine Sources to Functional Products is a detailed guide to the use of biopolymers for advanced applications across a range of key industries. In terms of processing and cost, bio-based polymers are becoming increasingly viable for an ever-broadening range of novel industrial applications. The book begins with an overview of biopolymers, explaining resources, demands, sustainability, life cycle assessment (LCA) modeling and simulation, and classifications. Further in-depth chapters explore the latest techniques and methodologies for isolation and physicochemical characterization, materials selection, and processing for blends and composites.
Chapters 6 to 14 each focus on the preparation and applications of biopolymers in a specific industrial area, including food science and nutraceuticals, medicine and pharmaceuticals, textiles, cosmeceutical, packaging, adhesives and automotive, 3D printing, super capacitor and energy storage devices, and environmental applications. The final chapter compares and analyzes biopolymers alongside synthetic polymers, also offering valuable insight into social, economic, and environmental aspects. This is an essential resource for those seeking to understand, research, or utilize biopolymers in industrial applications. This includes researchers, scientists, and advanced students working in biopolymers, polymer science, polymer chemistry, biomaterials, materials science, nanotechnology, composites, and biotechnology. This is a highly valuable book for scientists, R&D professionals, designers, and engineers across multiple industries and disciplines, who are looking to utilize biopolymers for components and products.
3D-scaffolds composed of polyvinyl alcohol-hyaluronan (PVA/HA) nanofiber mats were fabricated by electrospinner. Spinning conditions of PVA/HA were optimized for obtaining uniform and smooth nanofibers (NFs). Resultant NFs were investigated by SEM, FT-IR and mechanical tensile. Chitosan was incorporated into NFs mats during spinning for reducing bleeding, microbial growth of wound bed, and enhancing viability/proliferation of cells in damaged tissues. Hydroxyapatite (HAP) after silanization using (3-aminopropyl)triethoxysilane (APTES) was also incorporated into scaffolds due to its similar chemical composition with mineral composition of bone, which stimulates interactions between bone tissue and biomaterial resulting in a prominent interface after implantation. NFs with different compositions were bio-evaluated in vitro using antimicrobial activity, hemolysis(%), cytotoxicity, and cell adhesion tests. Results revealed that, addition of HAP into PVA/HA mats improved significantly their mechanical/thermal stability and relatively hindered swelling index, compared to mats without HAP. However, addition of chitosan enhanced swelling index and antimicrobial activity of mats. All tested mats with different compositions showed high cell-viability, regardless incubation time or concentration of tested nanofibers. In-vitro cell adhesion results indicated that, WI38 cells adhered and proliferated adequately with nanofibers containing HAP. Such findings support the ability for using PVA/HA/CH/HAP NFs as biomaterials for bone tissue regeneration soon.
Polymeric tissue adhesives provide versatile materials for wound management and are widely used in a variety of medical settings ranging from minor to life-threatening tissue injuries. Compared to the traditional methods of wound closure (i.e., suturing and stapling), they are relatively easy to use, enable rapid application, and introduce minimal tissue damage. Furthermore, they can act as hemostats to control bleeding and provide a tissue-healing environment at the wound site. Despite their numerous current applications, tissue adhesives still face several limitations and unresolved challenges (e.g., weak adhesion strength and poor mechanical properties) that limit their use, leaving ample room for future improvements. Successful development of next-generation adhesives will likely require a holistic understanding of the chemical and physical properties of the tissue-adhesive interface, fundamental mechanisms of tissue adhesion, and requirements for specific clinical applications. In this review, we discuss a set of rational guidelines for design of adhesives, recent progress in the field along with examples of commercially available adhesives and those under development, tissue-specific considerations, and finally potential functions for future adhesives. Advances in tissue adhesives will open new avenues for wound care and potentially provide potent therapeutics for various medical applications.
Polymeric materials have been thriving in global industries over the past 5 decades because of their adaptability, durability, and price, so much so that now we cannot imagine a product that does not contain them. However, many synthetic polymers that have been developed are mainly derived from petroleum and coal as raw material, which make them incompatible with the environment, since they cannot be included in what is a natural recycling system. Aware of the environmental impacts that produce synthetic polymers, a solution could be mixtures with different types and sources of biological materials, called biopolymers, such as starch, cellulose, chitin, chitosan, zein, and gelatin among others, which could gradually replace synthetic polymers to address and resolve these problems. The naturally obtained and synthetic biopolymers possess huge advantages over petroleum-based polymers by means of cost effectiveness, eco-friendliness, and user-friendly materials. In this chapter, we discuss the advantages of biopolymers over synthetic polymers in social, economic, and environmental aspects. The life cycle assessment of various biopolymers is compared with the petroleum-based biopolymers and the results show that biopolymers have certain advantages. Furthermore, the impact created on the environment by petroleum-based plastics is higher than that of biopolymers. The discussion is further extended to the composite materials of biopolymers with synthetic polymers to reduce impacts on the environment. Moreover, the utilization of turmeric nanofibers and ginger nanofibers derived from biowastes such as turmeric and ginger spent and their composites with different biopolymers and metal oxides in environmental applications, drug delivery, and antibacterial studies is also elaborated. Advanced applications of biopolymers in medical, tissue-engineering, military, and environmental applications suggest that biopolymers are a boon for the Earth over synthetic polymers.
An injectable, click-crosslinking (Cx) hyaluronic acid (HA) hydrogel scaffold modified with a bone morphogenetic protein-2 (BMP-2) mimetic peptide (BP) was prepared for bone tissue engineering applications. The injectable click-crosslinking HA formulation was prepared from HA-tetrazine (HA-Tet) and HA-cyclooctene (HA-TCO). The Cx-HA hydrogel scaffold was prepared simply by mixing HA-Tet and HA-TCO. The Cx-HA hydrogel scaffold was stable for a longer period than HA both in vitro and in vivo, which was verified via in-vivo fluorescence imaging in real time. BP acted as an osteogenic differentiation factor for human dental pulp stem cells (hDPSCs). After its formation in vivo, the Cx-HA scaffold provided a fine environment for the hDPSCs, and the biocompatibility of the hydrogel scaffold with tissue was good. Like traditional BMP-2, BP induced the osteogenic differentiation of hDPSCs in vitro. The physical properties and injectability of the chemically loaded BP for the Cx-HA hydrogel (Cx-HA-BP) were nearly identical to those of the physically loaded BP hydrogels and the Cx-HA-BP formulation quickly formed a hydrogel scaffold in vivo. The chemically loaded hydrogel scaffold retained the BP for over a month. The Cx-HA-BP hydrogel was better at inducing the osteogenic differentiation of loaded hDPSCs, because it prolonged the availability of BP. In summary, we successfully developed an injectable, click-crosslinking Cx-HA hydrogel scaffold to prolong the availability of BP for efficient bone tissue engineering.
Bioprinting is rapidly being adopted as a major method for fabricating tissue engineering constructs. Through the precise deposition of cell- and bioactive molecule-laden materials, bioprinting offers researchers a means to create biological constructs with enhanced spatial complexity that more closely mimics native tissue. The vast majority of materials used in bioprinting have been polymers due to their suitability toward resembling the cellular environment and the variety of methods available to process polymeric systems in ambient or relatively mild chemical and environmental conditions. In this review, we will discuss in detail the wide variety of natural and synthetic polymers that have been employed as inks in bioprinting. We will review recent bioprinting innovations, such as increasing architectural complexity and cell viability in heterogeneous tissue constructs, which allow for the investigation of biological questions that could not be addressed before. We will also survey nascent fields of study that promise to further advance the development of novel biofabrication technologies in the field, such as 4D bioprinting and the inclusion of nanomaterials. To conclude, we will examine some of the necessary steps that must take place to bring this technology to commercial markets and facilitate its use in clinical therapies.
The ability to fabricate sensory systems capable of highly selective operation in complex fluid will undoubtedly underpin key future developments in healthcare. However, the abundance of (bio)molecules in these samples can significantly impede performance at the transducing interface where nonspecific adsorption (fouling) can both block specific signal (reducing sensitivity) and greatly reduce assay specificity. Herein, we aim to provide a comprehensive review discussing concepts and recent advances in the construction of antifouling sensors that are, through the use of chemical, physical, or biological engineering, capable of operating in complex sample matrix (e.g., serum). We specifically highlight a range of molecular approaches to the construction of solid sensory interfaces (planar and nanoparticulate) and their characterization and performance in diverse in vitro and in vivo analyte (e.g., proteins, nucleic acids, cells, neuronal transmitters) detection applications via derived selective optical or electrochemical strategies. We specifically highlight those sensors that are capable of detection in complex media or those based on novel architectures/approaches. Finally, we provide perspectives on future developments in this rapidly evolving field. CONTENTS
Air-jet spinning has been used to fabricate fibers with nano-micro diameters and is widely applied in medical products such as wound treatment patches, gauze, and graft scaffolds. In particular, wounds vary from light to deep, and basically the wound is vulnerable to infection by external harmful factors. Therefore, blocking harmful factors from entering the wound area is very important. In addition, the wound site has high levels of oxidative stress, and thus the use of antioxidants is suggested as a good solution for wound treatment. We developed wound healing agents using gelatin, which shows excellent biocompatibility, catechin, which has high antioxidant activity, and polycaprolactone, which was spun on catechin and gelatin films, to produce a double layered structure using air-jet spinning. This structure blocked harmful external factors and is a candidate for efficient wound treatment.
The functional conjugations with natural polyphenols could be a working strategy for accomplishing the degradation resistance of hyaluronic acids (HA). Herein, a series of HA conjugates with four different polyphenols with wide ranges in the degree of substitution were systematically prepared. The degradation rate could be retarded in a wide range without crosslinking: The conjugates having polyphenolic aglycone (catechin or quercetin) maintained their structures, as identified by viscosity, for up to 7 weeks in the presence of hyaluronidase. This retardation was outstanding compared to those reported from previous studies, and the physical mixtures of HA and polyphenols still showed significantly more retarded degradation than pristine HA. The degradation resistance could be controlled by varying the feed ratio of polyphenols. This conjugation method of polyphenols could open up new application areas of HA with the outstanding degradation resistance.
Polysaccharide-based hydrogel particles have attracted attention as promising carriers for various biomolecules and drugs owing to their biocompatibility and biodegradability. The network structure and hydrophilic features of these hydrogels result in large surface area and high water uptake, which allows them to effectively store active molecules. However, conventional protocols for synthesizing such hydrogel nanoparticles usually require high amounts of organic solvents and cross-linkers, which may cause potential toxicity issues. Herein, we present a method for the water-phase synthesis of hyaluronic acid-based hydrogel particles (HAGs) and their application for safely encapsulating biomolecules. By controlling the synthesis procedures and ingredients, the size and shape of the HAGs can be systematically optimized. The colloidal stability of the produced HAGs is evaluated by measuring their light-scattering properties under various conditions. The activity of loaded molecules, such as small antioxidants and large proteins, is also monitored via activity assays. Finally, controlled release of the loaded molecules is achieved via the enzymatic degradation of hyaluronic acid. We believe that the proposed HAGs could be used as promising carriers for protecting active ingredients from the outer environment to further develop biomedical and cosmetic products.
Nano- and microfibers based on biopolymers are some of the most attractive issues of biotechnology due to their unique properties and effectiveness. Hyaluronan is well-known as a biodegradable, naturally-occurring polymer, which has great potential for being utilized in a fibrous form. The obtaining of fibers from hyaluronan presents a major challenge because of the hydrophilic character of the polymer and the high viscosity level of its solutions. Electrospinning, as the advanced and effective method of the fiber generation, is difficult. The nano- and microfibers from hyaluronan may be obtained by utilizing special techniques, including binary/ternary solvent systems and several polymers described as modifying (or carrying), such as polyethylene oxide (PEO) and polyvinyl alcohol (PVA). This paper reviews various methods for the synthesis of hyaluronan-based fibers, and also collects brief information on the properties and biological activity of hyaluronan and fibrous materials based on it.
Cellular remodeling of the matrix has recently emerged as a key factor in promoting neural differentiation. Most strategies to manipulate matrix remodeling focus on proteolytically cleavable crosslinkers, leading to changes in tethered biochemical signaling and matrix properties. Using peptides that are not the direct target of enzymatic degradation will likely reduce changes in the matrix and improve control of biological behavior. In this study, laminin derived peptides, IKVAV and LRE, tethered to independent sites in hyaluronic acid matrices using Michael addition and strain-promoted azide–alkyne cycloaddition are sufficient to manipulate hyaluronic acid degradation, gelatinase expression and protease expression, while promoting neurite extension through matrix metalloprotease dependent mechanisms in mouse embryonic stem cells encapsulated in hyaluronic acid matrices using an oxidation-reduction reaction initiated thiol-ene chemistry gelation. This study provides the foundation for a new strategy to stimulate matrix remodeling that is not dependent on enzymatic cleavage targets.
Differential scanning calorimetry (DSC) was used to distinguish three types of water of hydration in sodium hyaluronate and ethyl, benzyl. and partial benzyl esters of hyaluronic acid. These three rypes were defined as follows: type I: free, freezing water (freezin9 temperature = 0 " C); type II: weakly bound, freezing water (freezing temperature < 0'C); and type III: strongly bound, non-freezing water. Samples were scanned from (-) 50 to 20 ' C at a rate of 2.5" C/min. In the case of sodium hyaluronate, the onset temperature of melting deviated from that of pure water; such deviation was not observed for the esters of hyaluronic acid. 9-21 mol $pe III water were associated with each polymer repeat unit, with the value depending on the rype of ester and degree of esterification. Hydrated sodium hyaluronate powder samples stored at (-) 50 ' C for up to 29 h did not show any changes in onset temperature and heat of fusion values, suggesting that the kinetics of freezing did not greatly influence the results. In hydrated benzyl ester and partial benzyl ester membranes, a good correlation was found between the percent of freezable water and permeability coefficients for various model compounds, suggesting that these solutes may be transported primarily in freezable water.
The transport properties of thin films formed from hyaluronic acid esters have been studied. The permeabilities of the films to various solutes, the partition coefficients for a series of alkyl parabens, the rate and extent of hydration, and the release of a model compound were used as indicators of transport behavior. All the films tested had permeabilities to small neutral and positively charged solutes that were greater than 1 × 10-5 cm/s. Smaller permeability values were observed for negatively charged solutes, and for solutes with molecular weights greater than 3000 amu. The partition coefficients (Cmembrane/Cbuffer) for a series of alkyl parabens into a benzyl ester film varied from 12 to 41, and increased with increasing alkyi chain length of the paraben, indicating a partial hydrophobic character of the hydrated films. The films hydrated to a significant degree in distilled water (20 to 260% weight increase); the degree of hydration depended on the alcohol used to form the ester. A correlation between the permeability of the films to ethyl paraben and the degree of polymer hydration was observed. The release of a model compound (chlorpromazine) that was physically incorporated into the films was rapid, with complete release occurring in less than 200 minutes. This rapid release is consistent with the high degree of hydration and high permeability of the films.
The thermomechanical properties of fibres of two hyaluronic acid esters have been evaluated. The materials are found to be significantly different in hydrophilicity, reflected also in variations in mechanical and viscoelastic properties. Both esters show a marked decrease in strength in the swollen state.
When human peripheral monocytes and rabbit peritoneal macrophages were incubated with hyaluronic acid, the media were found to contain interleukin-1 (IL-1) activity and to stimulate collagenase production by rabbit fibroblasts. A digestion of hyaluronic acid by testicular hyaluronidase decreased the IL-1 inducing activity. Polymixin B, an inhibitor of endotoxin, did not exert any effect towards the action of hyaluronic acid. Hyaluronic acid also stimulated human polymorphonuclear leucocytes to produce IL-1 like activity. These results indicate that hyaluronic acid is an endogenous IL-1 inducer and may play important roles in the pathological and/or physiological changes of connective tissues.
A nerve guide made of a benzyl ester of hyaluronic acid (HYAFF11p75) was used to bridge 8 mm gaps in rat tibial nerves. Histologic observations indicated that this biomaterial provoked only a transient, modest inflammatory response, and the resorption rate was compatible with the nerve regeneration processes. Phagocytosis of the biomaterial began after neoangiogenesis and cell migration had taken place from both stumps into the nerve guide material. For comparison, the regeneration achieved was evaluated in nerve guides made of either HYAFF11p75 or Silastic, and in nerves repaired with the autograft technique. Recovery was assessed in vivo 90 days after implantation by measuring the nerve compound action potential (CAP) and conduction velocity (NCV) of the regenerated tibial nerve. The results demonstrate that the nerve guide tubes made of HYAFF11p75 were able to support and direct axonal growth, thereby suggesting a possible use for such biomaterial in the management of short nerve gaps in human pathology.
The enzymic degradation of hyaluronan in mammalian tissues takes place in two phases, encompassing breakdown of the polysaccharide to its monosaccharide constituents and subsequent utilization of the monosaccharide products. Degradation to the monosaccharide components is effected by the concerted action of three enzymes, hyaluronidase, beta-D-glucuronidase and beta-N-acetyl-D-hexosaminidase. The relative contributions of hyaluronidase and the two exoglycosidases to the physiological catabolism of hyaluronan are not yet known but consideration of the kinetic properties of the three enzymes clearly indicates that hyaluronidase is best suited for the initial attack on the polysaccharide, inasmuch as its Km for hyaluronan is 1000- to 10,000-fold lower than that estimated for beta-D-glucuronidase. Recent investigations in the authors' laboratories have been focused on the catabolism of hyaluronan and other complex carbohydrates in liver, since the sinusoidal endothelial cells in this organ are the main sites for degradation of circulating hyaluronan. Assay of ten lysosomal hydrolases in isolated rat liver cells showed considerably higher activities in Kupffer cells and endothelial cells than in hepatocytes for nine of the enzymes, including beta-D-glucuronidase and beta-N-acetyl-D-hexosaminidase. The activity of N-acetylglucosamine-6-phosphate deacetylase, a key enzyme in the metabolism of the N-acetylglucosamine released by the lysosomal degradation of hyaluronan and other complex carbohydrates, has also been determined. High deacetylase activities were observed in both Kupffer cells and endothelial cells but, surprisingly, virtually no activity was detected in hepatocytes. This finding implies that N-acetylglucosamine cannot be degraded in hepatocytes and must be largely reutilized in the synthesis of new macromolecules. Further studies of the enzymes involved in hyaluronan degradation and N-acetylglucosamine utilization in the liver are under way.
To test the scavenging of reactive oxygen species (ROS), we added synovial fluids from patients with rheumatoid arthritis (RA) and osteoarthritis, as well as hyaluronic acid (HA) and its 2 subcomponents, D-glucuronic acid and N-acetyl-D-glucosamine, to 2 ROS-generating systems, activated neutrophils and xanthine-xanthine oxidase. Synovial fluid from RA patients, HA, and D-glucuronic acid markedly decreased the O2-, H2O2, OH., and chemiluminescence measured in both systems. HA and synovial fluid, which are known to be susceptible to degradation by excessive ROS in RA patients, also seem to play an active role in protecting articular tissues from oxidative damage.
Previous investigations have demonstrated that the function of polymorphonuclear leukocytes (PMN) is stimulated by hyaluronic acid (HA). The aim of the present investigation was to study the molecular basis for the effect of HA. HA fragments of m.w. in the range from 792 (tetrasaccharide) to 3,000,000 all stimulated the chemotactic and phagocytic function of PMN. The active concentration ranged from 4 to 64 pmol/liter, irrespective of the molecular size. Further investigations demonstrated that N-acetyl-D-glucosamine (NAGA) was the smallest active fragment of HA. NAGA is one of the components from which HA is built up; the other component glucuronic acid was without effect, and so were the other glycosaminoglycans, N-acetyl-D-mannosamine, N-acetyl-D-galactosamine, and D-glucosamine. Finally, Con A, the glucopyranosyl and glucomannosyl binding lectin, inhibited the stimulatory effect of NAGA. As is the case with HA, fibronectin also acts as a necessary cofactor to NAGA when incubations are made in the absence of whole blood or serum. The present results strongly indicated that the combined action of NAGA and fibronectin worked directly on the PMN by an interaction at the cellular membrane level. We conclude that the stimulatory action of HA on granulocyte functions is mediated through one of its two structural components, i.e., NAGA.
The proliferation of rabbit synovial cells, 3T3 cells, or simian virus-transformed 3T3 cells in cell culture was inhibited by the addition of hyaluronate to the culture medium. This effect was markedly dependent on the molecular weight and concentration of the hyaluronate. At the molecular weight and concentration of hyaluronate present in normal synovial fluid, proliferation was inhibited. At lower molecular weights or concentrations, as found in rheumatoid synovial fluid, hyaluronate was significantly less inhibitory. Thus, the changes in synovial fluid hyaluronate that are associated with arthropathies may contribute to a favorable environment for rheumatoid pannus expansion.
Inhibition of human endothelial cell proliferation by hyaluronic acid (abstr)
- Hirata
The molecular basis of the hyaluronic acid mediated stimulation of granulocyte function
- Hakensson