Chitin-based materials in tissue engineering: applications in soft tissue and epithelial organ

New Insights into Sources, Bioavailability, Health-Promoting Effects, and Applications of Chitin and Chitosan

Chitin and chitosan are mostly derived from the exoskeletons of crustaceans, insects, and fungi. Chitin is the second most abundant biopolymer after cellulose, and it is a fibrous polysaccharide which resists enzymatic degradation in the stomach but undergoes microbial fermentation in the colon, producing beneficial metabolites. Chitosan, which is more soluble in the alkaline small intestine, is more susceptible to enzymatic action. Both biopolymers show limited absorption into the bloodstream, with smaller particles exhibiting better bioavailability. The health effects include anti-inflammatory properties, potential in immune system modulation, impacts on cholesterol levels, and antimicrobial effects, with a specific focus on implications for gut health. Chitin and chitosan exhibit anti-inflammatory properties by interacting with immune cells, influencing cytokine production, and modulating immune responses, which may benefit conditions characterized by chronic inflammation. These biopolymers can impact cholesterol levels by binding to dietary fats and reducing lipid absorption. Additionally, their antimicrobial properties contribute to gut health by controlling harmful pathogens and promoting beneficial gut microbiota. This review explores the extensive health benefits and applications of chitin and chitosan, providing a detailed examination of their chemical compositions, dietary sources, and applications, and critically assessing their health-promoting effects in the context of human well-being.

Chitosan as a tool for tissue engineering and rehabilitation: Recent developments and future perspectives - A review

Chitosan has established itself as a multifunctional and auspicious biomaterial within the domain of tissue engineering, presenting a decade of uninterrupted advancements and novel implementations. This article provides a comprehensive overview of the most recent developments in chitosan-based tissue engineering, focusing on significant progress made in the last ten years. An exploration is conducted of the various techniques utilized in the modification of chitosan and the production of scaffolds, with an analysis of their effects on cellular reactions and tissue regeneration. The investigation focuses on the integration of chitosan with other biomaterials and the addition of bioactive agents to improve their functionalities. Upon careful analysis of the in vitro and in vivo research, it becomes evident that chitosan effectively stimulates cell adhesion, proliferation, and differentiation. Furthermore, we offer valuable perspectives on the dynamic realm of chitosan-based approaches tailored to distinct tissue categories, including nerve, bone, cartilage, and skin. The review concludes with a discussion of prospective developments, with particular attention given to possible directions for additional study, translational implementations, and the utilization of chitosan to tackle existing obstacles in the field of tissue engineering. This extensive examination provides a significant amalgamation of the advancements achieved over the previous decade and directs scholars towards uncharted territories in chitosan-based tissue engineering.

Properties of Chitin and Its Regenerated Hydrogels from the Insect Zophobas morio Fed Citrus Biomass or Polystyrene

The potential of insects as a recycling tool has recently attracted attention. In this study, chitin was extracted with 1 M HCl for 24 h at 20 °C, followed by 1 M NaOH for 5 h at 90 °C, and bleached with 2.5% v/v NaOCl for 2 h at 20 °C from Zophobas morio (ZM) insects fed citrus waste biomass (OP) or polystyrene foam (PS). The highest survival rate was found in the OP group. The properties of the resulting chitin material are reported, as well as the preparation of hydrogels using a DMAc/LiCl solvent. All chitins obtained were α-chitin. The degrees of deacetylation, crystallinity, molecular weight, and solubility in DMAc/LiCl were similar between the PS and biomass feeds, and they showed similar viscosities in the DMAc/LiCl solution. All hydrogels obtained had similar properties and viscoelastic behavior, indicating that the resultant chitins and their hydrogels from ZM were similar between those fed with citrus biomass and those fed with PS.

A Spatiotemporal Controllable Biomimetic Skin for Accelerating Wound Repair

Skin injury repair is a dynamic process involving a series of interactions over time and space. Linking human physiological processes with materials' changes poses a significant challenge. To match the wound healing process, a spatiotemporal controllable biomimetic skin is developed, which comprises a three-dimensional (3D) printed membrane as the epidermis, a cell-containing hydrogel as the dermis, and a cytokine-laden hydrogel as the hypodermis. In the initial stage of the biomimetic skin repair wound, the membrane frame aids wound closure through pre-tension, while cells proliferate within the hydrogel. Next, as the frame disintegrates over time, cells released from the hydrogel migrate along the residual membrane. Throughout the process, continuous cytokines release from the hypodermis hydrogel ensures comprehensive nourishment. The findings reveal that in the rat full-thickness skin defect model, the biomimetic skin demonstrated a wound closure rate eight times higher than the blank group, and double the collagen content, particularly in the early repair process. Consequently, it is reasonable to infer that this biomimetic skin holds promising potential to accelerate wound closure and repair. This biomimetic skin with mechanobiological effects and spatiotemporal regulation emerges as a promising option for tissue regeneration engineering.

Chitosan-based materials for dental implantology: A comprehensive review

Chitosan, a versatile biopolymer, has gained recognition in the discipline of dental implantology due to possessing salient properties. This comprehensive review explores the potential of chitosan in dental implants, focusing on its biocompatibility, bioactivity, and the various chitosan-based materials that have been utilized for dental implant therapy. The review also highlights the importance of surface treatment in dental implants to enhance osseointegration and inhibit bacterial biofilm formation. Additionally, the chemical structure, properties, and sources of chitosan are described, along with its different structural forms. The characteristics of chitosan particularly color, molecular weight, viscosity, and degree of deacetylation are discussed about their influence on its applications. This review provides valuable insights into the promising utilization of polymeric chitosan in enhancing the success and functionality of dental implants. This study highlights the potential applications of chitosan in oral implantology. Chitosan possesses various advantageous properties, including muco-adhesiveness, hemostatic action, biocompatibility, biodegradability, bioactivity, and antibacterial and antifungal activities, which enhance its uses in dental implantology. However, it has limited aqueous solubility at the physiological pH, which sometimes restricts its biological application, but this problem can be overcome by using modified chitosan or chitosan derivatives, which have also shown encouraging results. Recent research suggests that chitosan may act as a promising material for coating titanium-based implants, improving osteointegration together with antibacterial properties.

Chitin: A versatile biopolymer-based functional therapy for cartilage regeneration

Chitin is the second most abundant biopolymer and its inherent biological characteristics make it ideal to use for tissue engineering. For many decades, its properties like non-toxicity, abundant availability, ease of modification, biodegradability, biocompatibility, and anti-microbial activity have made chitin an ideal biopolymer for drug delivery. Research studies have also shown many potential benefits of chitin in the formulation of functional therapy for cartilage regeneration. Chitin and its derivatives can be processed into 2D/3D scaffolds, hydrogels, films, exosomes, and nano-fibers, which make it a versatile and functional biopolymer in tissue engineering. Chitin is a biomimetic polymer that provides targeted delivery of mesenchymal stem cells, especially of chondrocytes at the injected donor sites to accelerate regeneration by enhancing cell proliferation and differentiation. Due to this property, chitin is considered an interesting polymer that has a high potential to provide targeted therapy in the regeneration of cartilage. Our paper presents an overview of the method of extraction, structure, properties, and functional role of this versatile biopolymer in tissue engineering, especially cartilage regeneration.

Effects of Chitosan on Chondrocytes Derived from Human Nasal Septal Cartilage

BACKGROUND/AIM

The aim of this study was to evaluate the influence of chitosan on the growth of nasal septal chondrocytes (NSCs). The final goal was to establish a novel methodology to enhance nasal septal cartilage regeneration.

MATERIALS AND METHODS

Human NSCs were isolated and their morphology was examined using Alcian blue staining and observed by light microscopy. The isolated NSCs were grown with various concentrations of chitosan and the expression of COL2A1 was investigated.

RESULTS

NSCs were successfully isolated from nasal septal cartilage. Co-culture with 0.2% of chitosan greatly enhanced proliferation of NSCs compared to control cells. However, 0.5% of chitosan was harmful to NSCs, resulting in cell detachment from the culture plate. Furthermore, the addition of 0.2% chitosan significantly improved the expression of COL2A1 in NSCs.

CONCLUSION

To our knowledge, this is the first report to demonstrate that chitosan could effectively guide the attachment and growth of human NSCs. Chitosan appears to be a promising additive for NSC culture, which sets the stage for studying tissue regeneration in nasal septal cartilage deficiency, rhinoplasty, and craniofacial reconstruction.

Commercialization of Ionic Liquids in Pursuit of Green Chemistry: Must we Each Become an Entrepreneur?

There will be common challenges to scaling-up any ionic liquids separations technologies which require very large volumes of ionic liquid. Some of these challenges are illustrated in this personal account which chronicles the extraction of chitin from shrimp shell from discovery to current commercialization efforts. The road being taken from discovery in an academic laboratory, through attempts to navigate the scaling-up to commercial scale using the vehicle of a faculty startup company is rewarding, but fraught with roadblocks, detours, and unexpected challenges. The differences in 'technically feasible' and 'commercially viable' are not always evident from the beginning of the journey, however, one wonders what achievements we miss as a Society because it was assumed to not be commercially viable.

Artificial ovaries constructed from biodegradable chitin-based hydrogels with the ability to restore ovarian endocrine function and alleviate osteoporosis in ovariectomized mice

BACKGROUND

Artificial ovary (AO) is an alternative approach to provide physiological hormone to post-menopausal women. The therapeutic effects of AO constructed using alginate (ALG) hydrogels are limited by their low angiogenic potential, rigidity, and non-degradability. To address these limitations, biodegradable chitin-based (CTP) hydrogels that promote cell proliferation and vascularization were synthesized, as supportive matrix.

METHODS

In vitro, follicles isolated from 10-12-days-old mice were cultured in 2D, ALG hydrogels, and CTP hydrogels. After 12 days of culture, follicle growth, steroid hormone levels, oocyte meiotic competence, and expression of folliculogenesis-related genes were monitored. Additionally, follicles isolated from 10-12-days-old mice were encapsulated in CTP and ALG hydrogels and transplanted into the peritoneal pockets of ovariectomised (OVX) mice. After transplantation, steroid hormone levels, body weight, rectal temperature, and visceral fat of the mice were monitored every two weeks. At 6 and 10 weeks after transplantation, the uterus, vagina, and femur were collected for histological examination.

RESULTS

The follicles developed normally in CTP hydrogels under in vitro culture conditions. Additionally, follicular diametre and survival rate, oestrogen production, and expression of folliculogenesis-related genes were significantly higher than those in ALG hydrogels. After one week of transplantation, the numbers of CD34-positive vessels and Ki-67-positive cells in CTP hydrogels were significantly higher than those in ALG hydrogels (P < 0.05), and the follicle recovery rate was significantly higher in CTP hydrogels (28%) than in ALG hydrogels (17.2%) (P < 0.05). After two weeks of transplantation, OVX mice implanted with CTP grafts exhibited normal steroid hormone levels, which were maintained until week eight. After 10 weeks of transplantation, CTP grafts effectively ameliorated bone loss and atrophy of the reproductive organs, as well as prevented the increase in body weight and rectal temperature in OVX mice, which were superior to those elicited by ALG grafts.

CONCLUSIONS

Our study is the first to demonstrate that CTP hydrogels support follicles longer than ALG hydrogels in vitro and in vivo. The results highlight the clinical potential of AO constructed using CTP hydrogels in the treatment of menopausal symptoms.

Effective Endotoxin Removal from Chitosan That Preserves Chemical Structure and Improves Compatibility with Immune Cells

Chitosan is one of the most researched biopolymers for healthcare applications, however, being a naturally derived polymer, it is susceptible to endotoxin contamination, which elicits pro-inflammatory responses, skewing chitosan's performance and leading to inaccurate conclusions. It is therefore critical that endotoxins are quantified and removed for in vivo use. Here, heat and mild NaOH treatment are investigated as facile endotoxin removal methods from chitosan. Both treatments effectively removed endotoxin to below the FDA limit for medical devices (<0.5 EU/mL). However, in co-culture with peripheral blood mononuclear cells (PBMCs), only NaOH-treated chitosan prevented TNF-α production. While endotoxin removal is the principal task, the preservation of chitosan's structure is vital for the synthesis and lysozyme degradation of chitosan-based hydrogels. The chemical properties of NaOH-treated chitosan (by FTIR-ATR) were significantly similar to its native composition, whereas the heat-treated chitosan evidenced macroscopic chemical and physical changes associated with the Maillard reaction, deeming this treatment unsuitable for further applications. Degradation studies conducted with lysozyme demonstrated that the degradation rates of native and NaOH-treated chitosan-genipin hydrogels were similar. In vitro co-culture studies showed that NaOH hydrogels did not negatively affect the cell viability of monocyte-derived dendritic cells (moDCs), nor induce phenotypical maturation or pro-inflammatory cytokine release.

Biocomposite films based on chitosan and cerium oxide nanoparticles with promising regenerative potential

Polymeric nanocomposite materials have great potential in the development of tissue-engineered scaffolds because they affect the structure and properties of polymeric materials and regulate cell proliferation and differentiation. In this work, cerium oxide nanoparticles (CeONPs) were incorporated into a chitosan (CS) film to improve the proliferation of multipotent mesenchymal stem cells (MSCs). The citrate-stabilized CeONPs with a negative ζ-potential (-25.0 mV) were precoated with CS to obtain positively charged particles (+20.3 mV) and to prevent their aggregation in the composite solution. The composite CS-CeONP films were prepared in the salt and basic forms using a dry-cast process. The films obtained in both forms were characterized by a uniform distribution of CeONPs. The incorporation of CeONPs into the salt form of CS increased the stiffness of the CS-CeONP film, while the subsequent conversion of the film to the basic form resulted in a decrease in both the Young's modulus and the yield stress. The redox activity (Ce⁴⁺ ⇌ Ce³⁺) of cerium oxide in the CS-CeONP film was confirmed by thermal oxidative degradation. In vitro culture of MSCs showed that the CS-CeONP film has good biocompatibility, and in vivo experiments demonstrated its substantial regenerative potential.

Structure and Composition of the Cuticle of the Goose Barnacle Pollicipes pollicipes: A Flexible Composite Biomaterial

Arthropods, the largest animal phylum, including insects, spiders and crustaceans, are characterized by their bodies being covered primarily in chitin. Besides being a source of this biopolymer, crustaceans have also attracted attention from biotechnology given their cuticles' remarkable and diverse mechanical properties. The goose barnacle, Pollicipes pollicipes, is a sessile crustacean characterized by their body parts covered with calcified plates and a peduncle attached to a substrate covered with a cuticle. In this work, the composition and structure of these plates and cuticle were characterized. The morphology of the tergum plate revealed a compact homogeneous structure of calcium carbonate, a typical composition among marine invertebrate hard structures. The cuticle consisted of an outer zone covered with scales and an inner homogenous zone, predominantly organic, composed of successive layers parallel to the surface. The scales are similar to the tergum plate and are arranged in parallel and oriented semi-vertically. Structural and biochemical characterization confirmed a bulk composition of ɑ-chitin and suggested the presence of elastin-based proteins and collagen. The mechanical properties of the cuticle showed that the stiffness values are within the range of values described in elastomers and soft crustacean cuticles resulting from molting. The removal of calcified components exposed round holes, detailed the structure of the lamina, and changed the protein properties, increasing the rigidity of the material. This flexible cuticle, predominantly inorganic, can provide bioinspiration for developing biocompatible and mechanically suitable biomaterials for diverse applications, including in tissue engineering approaches.

Probing the Structural Details of Chitin Nanocrystal-Water Interfaces by Three-Dimensional Atomic Force Microscopy

Chitin is one of the most abundant and renewable natural biopolymers. It exists in the form of crystalline microfibrils and is the basic structural building block of many biological materials. Its surface crystalline structure is yet to be reported at the molecular level. Herein, atomic force microscopy (AFM) in combination with molecular dynamics simulations reveals the molecular-scale structural details of the chitin nanocrystal (chitin NC)-water interface. High-resolution AFM images reveal the molecular details of chitin chain arrangements at the surfaces of individual chitin NCs, showing highly ordered, stable crystalline structures almost free of structural defects or disorder. 3D-AFM measurements with submolecular spatial resolution demonstrate that chitin NC surfaces interact strongly with interfacial water molecules creating stable, well-ordered hydration layers. Inhomogeneous encapsulation of the underlying chitin substrate by these hydration layers reflects the chitin NCs' multifaceted surface character with different chain arrangements and molecular packing. These findings provide important insights into chitin NC structures at the molecular level, which is critical for developing the properties of chitin-based nanomaterials. Furthermore, these results will contribute to a better understanding of the chemical and enzymatic hydrolysis of chitin and other native polysaccharides, which is also essential for the enzymatic conversion of biomass.

Citric acid cross-linked chitosan for inhibiting oxidative stress after nerve injury

Scaffold design is particularly important and necessary for soft tissue repair such as nerve tissue repair. In this article, we designed and manufactured a macroporous chitosan-based hydrogel with excellent cell compatibility and antioxidant properties. Here, the chitosan (CS) based hydrogel is obtained by repeated freezing and thawing using citric acid (CA) as a cross-linking agent. We have evaluated the effects of citric acid content on the physical and chemical properties of hydrogels through mechanical properties and scanning electron microscopy. CA-CS hydrogel shows a macroporous structure, as the citric acid increases, the mechanical strength increases and the pore size decreases. In vitro cell experiments show that CA-CS hydrogel partakes positive effects on cell survival, adhesion and proliferation, as well as antioxidant properties. All results provide a basis for the construction of porous chitosan-based hydrogels, while demonstrating a promising approach to deal with oxidative stress in nerve injury.

Mechanochemical Transformations of Biomass into Functional Materials

Biomass is one of the promising alternatives to petroleum-derived materials and plays a major role in our fight against climate change by providing renewable sources of chemicals and materials. Owing to its chemical and structural complexity, the transformation of biomass into value-added products requires a profound understanding of its composition at different scales and innovative methods such as combining physical and chemical processes. In this context, the use of mechanochemistry in biomass valorization is currently growing owing to its potentials as an efficient, sustainable, and environmentally friendly approach. This review highlights the latest advances in the transformation of biomass (i. e., chitin, cellulose, hemicellulose, lignin, and starch) to functional materials using mechanochemical-assisted methods. We focused here on the methodology of biomass processing, influencing factors, and resulting properties with an emphasis on achieving functional materials rather than breaking down the biopolymer chains into smaller molecules. Opportunities and limitations associated this methodology were discussed accordingly for future directions.

Biomedyczne właściwości chitozanu – zastosowanie w inżynierii tkankowej Biomedical properties of chitosan: Application in tissue engineering

Inżynieria tkankowa to interdyscyplinarna dziedzina badań, która stosuje zasady inżynierii i nauk przyrodniczych do opracowywania substytutów biologicznych, przywracania, utrzymywania lub poprawy funkcji tkanek. Łączy medycy-nę kliniczną, inżynierię mechaniczną, materiałoznawstwo i biologię molekularną. Chitozan jest związkiem, który może być stosowany na szeroką skalę w biomedycynie, m.in. jako nośnik leków, nici chirurgiczne, materiały opatrunkowe przeznaczone do przyspieszonego gojenia ran oraz rusztowania komórkowe w inżynierii tkankowej. Chitozon spełnia najważniejsze kryteria dla biomateriałów, m.in. kompatybilność, odpowiednie właściwości mechaniczne, morfologia i porowatość, nietoksyczność i biodegradowalność. Rusztowania chitozanowe mogą sprzyjać adhezji, różnicowaniu i proliferacji na powierzchni komórek. Z chitozanu można tworzyć różne formy funkcjonalne w zależności od potrzeb i wymagań, w tym: hydrożele 3D, gąbki 3D, folie i membrany oraz nanowłókna. Ze względu na unikalne właściwości fizykochemiczne biopolimer ten może być również wykorzystany do oczyszczania białek terapeutycznych z endotoksyn bakteryjnych, co jest dziś istotnym problemem w oczyszczaniu produktu końcowego w zastosowaniach medycznych. Obecnie terapie oparte na białkach rekombinowanych znajdują szerokie zastosowanie w terapiach celowanych, inżynierii tkankowej oraz szeroko pojętej medycynie regeneracyjnej. Dlatego tak ważny jest współistniejący, dobrze zapro-jektowany system oczyszczania produktu białkowego, który nie zmieni swoich zasadniczych właściwości. Artykuł jest przeglądem aktualnych badań nad zastosowaniem materiałów bioaktywnych na bazie chitozanu w medycynie regene-racyjnej różnych tkanek i narządów (m.in. tkanki chrzęstnej i kostnej, tkanki skórnej czy tkanki nerwowej).

Improving Polysaccharide-Based Chitin/Chitosan-Aerogel Materials by Learning from Genetics and Molecular Biology

Improved wound healing of burnt skin and skin lesions, as well as medical implants and replacement products, requires the support of synthetical matrices. Yet, producing synthetic biocompatible matrices that exhibit specialized flexibility, stability, and biodegradability is challenging. Synthetic chitin/chitosan matrices may provide the desired advantages for producing specialized grafts but must be modified to improve their properties. Synthetic chitin/chitosan hydrogel and aerogel techniques provide the advantages for improvement with a bioinspired view adapted from the natural molecular toolbox. To this end, animal genetics provide deep knowledge into which molecular key factors decisively influence the properties of natural chitin matrices. The genetically identified proteins and enzymes control chitin matrix assembly, architecture, and degradation. Combining synthetic chitin matrices with critical biological factors may point to the future direction with engineering materials of specific properties for biomedical applications such as burned skin or skin blistering and extensive lesions due to genetic diseases.

[Modern prerequisites for creating a collagen-based artificial analogue of the corneal stroma]

Despite the fact that various collagen biomaterials have been actively used in ophthalmology for more than 30 years, the problem of creating a material that could replace the donor cornea have not been solved. Recent advances in the field of tissue engineering and regenerative medicine have shifted the focus of approaches to solving the problem of creating an artificial cornea towards laying conditions for the restoration of its specific layers through mechanisms of its own cellular regeneration. In this regard, extracellular matrices based on collagen are gaining popularity. This review discusses general limitations and advantages of collagen for creating an artificial cornea.

Chitin Determination in Residual Streams Derived From Insect Production by LC-ECD and LC-MS/MS Methods

Chitin, a biopolymer present in fungi and arthropods, is a compound of interest for various applications, such as in the agricultural and medical fields. With the recently growing interest in the development of insect farming, the availability of chitin-containing residual streams, particularly the molting skins (exuviae), is expected to increase in the near future. For application purposes, accurate quantification of chitin in these insect sources is essential. Previous studies on chitin extraction and quantification often overlooked the purity of the extracted chitin, making the outcomes inconsistent and prone to overestimation. The present study aims to determine chitin content in the exuviae of three insect species mass-reared worldwide: black soldier fly (BSF), mealworm, and house cricket. Chitin was chemically extracted using acid and alkali treatments to remove minerals and proteins. The purity of extracted chitin was evaluated by hydrolyzing the chitin into glucosamine, followed by quantitative determination of the latter using two liquid chromatography methods: electrochemical detection (ECD) and tandem mass spectrometry (MS/MS). Both methods proved accurate and precise, without the need for labor-intensive derivatization steps. Pearson's correlation and Bland-Altman plots showed that the glucosamine determination results obtained by the two methods were comparable, and there is no consistent bias of one approach vs. the other. The chitin content in extracted residues ranged between 7.9 and 18.5%, with the highest amount found in BSF puparium. In summary, the study demonstrated that (1) the residual streams of the insect farming industry have a great potential for utilization as an alternative chitin source, and (2) both LC-ECD and LC-MS/MS are reliable for the quantitative determination of glucosamine in insect chitin.

Myelin-associated glycoprotein combined with chitin conduit inhibits painful neuroma formation after sciatic nerve transection

Studies have shown that myelin-associated glycoprotein (MAG) can inhibit axon regeneration after nerve injury. However, the effects of MAG on neuroma formation after peripheral nerve injury remain poorly understood. In this study, local injection of MAG combined with nerve cap made of chitin conduit was used to intervene with the formation of painful neuroma after sciatic nerve transfection in rats. After 8 weeks of combined treatment, the autotomy behaviors were reduced in rats subjected to sciatic nerve transfection, the mRNA expression of nerve growth factor, a pain marker, in the proximal nerve stump was decreased, the density of regenerated axons was decreased, the thickness of the myelin sheath was increased, and the ratio of unmyelinated to myelinated axons was reduced. Moereover, the percentage of collagen fiber area and the percentage of fibrosis marker alpha-smooth muscle actin positive staining area in the proximal nerve stump were decreased. The combined treatment exhibited superior effects in these measures to chitin conduit treatment alone. These findings suggest that MAG combined with chitin conduit synergistically inhibits the formation of painful neuroma after sciatic nerve transection and alleviates neuropathic pain. This study was approved by the Animal Ethics Committee of Peking University People’s Hospital (approval No. 2019PHE027) on December 5, 2019.

Fabrication and Characterization of Chitosan-Polyethylene Glycol (Ch-Peg) Based Hydrogels and Evaluation of Their Potency in Rat Skin Wound Model

Thermal burns are a major cause of death and suffering around the globe. They can cause debilitating, life-altering injuries as well as lead to significant psychological and financial consequences. Several research works have been conducted in attempt to find a wound healing therapy that is successful. At present, hydrogels have been widely used in cutting-edge research for this purpose because they have suitable properties. This study aimed to see how therapy with chitosan-polyethylene glycol (Ch-Peg) based hydrogels affected the healing of burn wounds in rats. With the concern of public health, xanthan gum (X), boric acid (B), gelatin (Ge), polyethylene glycol (Peg), chitosan (Ch), glutaraldehyde (G), and HPLC-grade water were prepared using X : Ge : G, X : Ge : Peg : G, X : Ge : Ch : G, X : Ge : Peg : Ch : G, X : Ge : B : Ch : G, X : Ge : B : Peg : G, and X : Ge : B : Peg : Ch : G. The produced composite hydrogels were examined for swelling ability, biodegradability, rheological characteristics, and porosity. The 3D structure of the hydrogel was revealed by scanning electron microscopy (SEM). After that, the structural characterization technique named Fourier-transform infrared spectroscopy (FTIR) was used to describe the composites (SEM). Lastly, in a rat skin wound model, the efficacy of the produced hydrogels was studied. Swelling ability, biodegradability, rheological properties, and porosity were all demonstrated in composite hydrogels that contained over 90% water. Hydrogels with good polymeric networks and porosity were observed using SEM. The existence of bound water and free, intra- and intermolecule hydrogen-linked OH and NH in the hydrogels was confirmed using FTIR. In a secondary burned rat model, all hydrogels showed significant wound healing effectiveness when compared to controls. When compared to other composite hydrogels, wounds treated with X : Ge : Peg : Ch : G, X : Ge : B : Peg : G, and X : Ge : B : Peg : Ch:G recovered faster after 28 days. In conclusion, this research suggests that X : Ge : Peg : Ch : G, X : Ge : B : Peg : G, and X : Ge : B : Peg : Ch : G could be used to treat skin injuries in the clinic.

Chitin Cryogels Prepared by Regeneration from Phosphoric Acid Solutions

Cryogelation is a developing technique for the production of polysaccharide materials for biomedical applications. The formation of a macroporous structure during the freeze-drying of polysaccharide solutions creates biomaterials suitable for tissue engineering. Due to its availability, biocompatibility, biodegradability, and non-toxicity, chitin is a promising natural polysaccharide for the production of porous materials for tissue engineering; however, its use is limited due to the difficulty of dissolving it. This work describes the preparation of cryogels using phosphoric acid as the solvent. Compared to typical chitin solvents phosphoric acid can be easily removed from the product and recovered. The effects of chitin dissolution conditions on the structure and properties of cryogels were studied. Lightweight (ρ 0.025-0.059 g/cm3), highly porous (96-98%) chitin cryogels with various heterogeneous morphology were produced at a dissolution temperature of 20 ± 3 °C, a chitin concentration of 3-15%, and a dissolution time of 6-25 h. The crystallinity of the chitin and chitin cryogels was evaluated by 13C CP-MAS NMR spectroscopy and X-ray diffractometry. Using FTIR spectroscopy, no phosphoric acid esters were found in the chitin cryogels. The cryogels had compressive modulus E values from 118-345 kPa and specific surface areas of 0.3-0.7 m2/g. The results indicate that chitin cryogels can be promising biomaterials for tissue engineering.

Hydroxypropyl chitosan/soy isolate protein conduits promote peripheral nerve regeneration

Designing scaffolds, with optimized micro-structure and function for promoting the release of neuro-related factors, is significant in peripheral nerve regeneration. Herein, a series of hydroxypropyl chitosan/soy protein isolate composite sponges (HCSS) were fabricated by a freeze-drying technique. The physicochemical properties of the resultant HCSS were examined by a Fourier infrared spectrometer, X-ray diffractometer, scanning electron microscope, water absorption assay, water retention assay, and compressive strength assay. The results indicated that HCSS exhibited an interconnected porous micro-structure and a high water retention ratio with the increase in SPI content. The biological characterization found that the HCSS-50 containing 50% SPI content profoundly promoted the proliferation of RSC96 cells and the secretion of neuro-related factors without excessive ROS production. In addition, HCSS-50 could significantly promote the expression of neuro-related factors; for example, the expression of TGF-β was 3 times higher than that of the control group. Finally, an optimized HCSS-based conduit was fabricated from HCSS-50 to repair sciatic nerve injury in rats with the combination of BMSCs or BMSC-derived Schwann cells. The results suggested that the constructed HCSS-based conduit accompanying BMSC-derived Schwann cells could effectively promote axonal regeneration and upregulate expression of neuro-related factors such as Krox20, Zeb2, and GAP43. Collectively, a newly engineered nerve conduit system was developed by incorporating HCSS-50 and BMSC-derived Schwann cells, which could be an alternative candidate for peripheral nerve regeneration.

Chitosan/Hyaluronic acid/Alginate and an assorted polymers loaded with honey, plant, and marine compounds for progressive wound healing-Know-how

Biomaterials are being extensively used in regenerative medicine including tissue engineering applications, as these enhance tissue development, repair, and help in the process of angiogenesis. Wound healing is a crucial biological process of regeneration of ruptured tissue after getting injury to the skin and other soft tissue in humans and animals. Besides, the accumulation of microbial biofilms around the wound surface can increase the risk and physically obstruct the wound healing activity, and may even lead to amputation. Hence, in both acute and chronic wounds, prominent biomaterials are required for wound healing along with antimicrobial agents. This review comprehensively addresses the antimicrobial and wound healing effects of chitosan, chitin, cellulose acetate, hyaluronic acid, pullulan, bacterial cellulose, fibrin, alginate, etc. based wound dressing biomaterials fabricated with natural resources such as honey, plant bioactive compounds, and marine-based polymers. Due to their excellent biocompatibility and biodegradability, bioactive compounds derived from honey, plants, and marine resources are commonly used in biomedical and tissue engineering applications. Different types of polymer-based biomaterials including hydrogel, film, scaffold, nanofiber, and sponge dressings fabricated with bioactive agents including honey, curcumin, tannin, quercetin, andrographolide, gelatin, carrageenan, etc., can exhibit significant wound healing process in, diabetic wounds, diabetic ulcers, and burns, and help in cartilage repair along with good biocompatibility and antimicrobial effects. Among the reviewed biomaterials, carbohydrate polymers such as chitosan-based biomaterials are prominent and widely used for wound healing applications followed by hyaluronic acid and alginate-based biomaterials loaded with honey, plant, and marine compounds. This review first provides an overview of the vast natural resources used to formulate different biomaterials for the treatment of antimicrobial, acute, and chronic wound healing processes.

Screening and Identification of Sponge-Associated Chitinolytic Bacteria by Forming Chitosan from Manado Bay, Indonesia

BACKGROUND AND OBJECTIVE

Chitosan can be produced through the enzymatic process catalyzed by chitin deacetylase which can be produced by bacteria. The biotransformation of chitin to chitosan by bacteria is interesting because the process is economical and environmentally friendly. This study described the potential of sponge-associated bacterium capability in degrading chitin and forming chitosan.

MATERIALS AND METHODS

The bacteria were isolated from sponge Cribrochalina sp. at Manado Bay, Indonesia. In the screening of the chitinase activity of bacteria, chitin media was used. Meanwhile, the transformation of chitin to chitosan was tested by using Chitinase Degrading Activity media. Molecular identification of bacteria was based on 16S rRNA gene sequences.

RESULTS

The results showed that the SS1, SS2, SS3, SS4 and SS5 bacterial isolates could degrade chitin based on chitinolytic indexes. These five bacteria could also form chitosan exhibited through the presence of chitosan in the form of precipitation in the fermented broth of bacteria. SS1 had the highest chitinase activity based on the chitinolytic index identified as Bacillus subtilis (100% identity), hence it is called B. subtilis strain SS1. The partial rRNA gene sequences data were deposited at GenBank under accession number MN999892.

CONCLUSION

The bacteria strain isolated from Cribrochalina sp. can be utilized in degrading chitin and form chitosan which could be a promising candidate for an economical and eco-friendly process of chitosan.

Fish Waste: From Problem to Valuable Resource

Following the growth of the global population and the subsequent rapid increase in urbanization and industrialization, the fisheries and aquaculture production has seen a massive increase driven mainly by the development of fishing technologies. Accordingly, a remarkable increase in the amount of fish waste has been produced around the world; it has been estimated that about two-thirds of the total amount of fish is discarded as waste, creating huge economic and environmental concerns. For this reason, the disposal and recycling of these wastes has become a key issue to be resolved. With the growing attention of the circular economy, the exploitation of underused or discarded marine material can represent a sustainable strategy for the realization of a circular bioeconomy, with the production of materials with high added value. In this study, we underline the enormous role that fish waste can have in the socio-economic sector. This review presents the different compounds with high commercial value obtained by fish byproducts, including collagen, enzymes, and bioactive peptides, and lists their possible applications in different fields.

Effect of the Degree of Acetylation of Chitin Nonwoven Fabrics for Promoting Wound Healing

Chitin and chitosan have been extensively used as wound dressings because of their special functions to promote wound healing. However, there was little focus on the effects of the degree of acetylation (DA) on wound healing. In this work, the regenerated chitin nonwoven fabrics with DA values of 90, 71, 60, and 42% were prepared, and the morphology and physical performances of the fabrics were characterized. Moreover, the effects of DA of the chitin nonwoven fabrics on wound recovery were studied with a full-thickness skin defect model in rats. In vitro experiments indicated that the chitin nonwoven fabrics exhibited good biocompatibility and blood compatibility and a low blood-clotting index (BCI). In vivo experiments revealed that the chitin nonwoven fabrics could accelerate wound healing more effectively than gauze by promoting re-epithelialization and collagen deposition as well as by stimulating neovascularization. The results of the wound healing process showed that DA of the chitin nonwoven fabrics had a profound effect on promoting wound healing. Notably, the regenerated chitin nonwoven fabrics with 71% DA significantly improved the wound healing compared to the commercial wound dressing Algoplaque film. Therefore, the regenerated chitin nonwoven fabrics are promising candidates for wound healing.

Genome-wide identification of chitinase genes in Thalassiosira pseudonana and analysis of their expression under abiotic stresses

BACKGROUND

The nitrogen-containing polysaccharide chitin is the second most abundant biopolymer on earth and is found in the cell walls of diatoms, where it serves as a scaffold for biosilica deposition. Diatom chitin is an important source of carbon and nitrogen in the marine environment, but surprisingly little is known about basic chitinase metabolism in diatoms.

RESULTS

Here, we identify and fully characterize 24 chitinase genes from the model centric diatom Thalassiosira pseudonana. We demonstrate that their expression is broadly upregulated under abiotic stresses, despite the fact that chitinase activity itself remains unchanged, and we discuss several explanations for this result. We also examine the potential transcriptional complexity of the intron-rich T. pseudonana chitinase genes and provide evidence for two separate tandem duplication events during their evolution.

CONCLUSIONS

Given the many applications of chitin and chitin derivatives in suture production, wound healing, drug delivery, and other processes, new insight into diatom chitin metabolism has both theoretical and practical value.

Challenges in Bone Tissue Regeneration: Stem Cell Therapy, Biofunctionality and Antimicrobial Properties of Novel Materials and Its Evolution

An aging population leads to increasing demand for sustained quality of life with the aid of novel implants. Patients expect fast healing and few complications after surgery. Increased biofunctionality and antimicrobial behavior of implants, in combination with supportive stem cell therapy, can meet these expectations. Recent research in the field of bone implants and the implementation of autologous mesenchymal stem cells in the treatment of bone defects is outlined and evaluated in this review. The article highlights several advantages, limitations and advances for metal-, ceramic- and polymer-based implants and discusses the future need for high-throughput screening systems used in the evaluation of novel developed materials and stem cell therapies. Automated cell culture systems, microarray assays or microfluidic devices are required to efficiently analyze the increasing number of new materials and stem cell-assisted therapies. Approaches described in the literature to improve biocompatibility, biofunctionality and stem cell differentiation efficiencies of implants range from the design of drug-laden nanoparticles to chemical modification and the selection of materials that mimic the natural tissue. Combining suitable implants with mesenchymal stem cell treatment promises to shorten healing time and increase treatment success. Most research studies focus on creating antibacterial materials or modifying implants with antibacterial coatings in order to address the increasing number of complications after surgeries that are mostly caused by bacterial infections. Moreover, treatment of multiresistant pathogens will pose even bigger challenges in hospitals in the future, according to the World Health Organization (WHO). These antibacterial materials will help to reduce infections after surgery and the number of antibiotic treatments that contribute to the emergence of new multiresistant pathogens, whilst the antibacterial implants will help reduce the amount of antibiotics used in clinical treatment.

Nanoscale mechanical properties of chitosan hydrogels as revealed by AFM

In the context of tissue engineering, chitosan hydrogels are attractive biomaterials because they represent a family of natural polymers exhibiting several suitable features (cytocompatibility, bioresorbability, wound healing, bacteriostatic and fungistatic properties, structural similarity with glycosaminoglycans), and tunable mechanical properties. Optimizing the design of these biomaterials requires fine knowledge of its physical characteristics prior to assessment of the cell-biomaterial interactions. In this work, using atomic force microscopy (AFM), we report a characterization of mechanical and topographical properties at the submicron range of chitosan hydrogels, depending on physico-chemical parameters such as their polymer concentration (1.5%, 2.5% and 3.5%), their degree of acetylation (4% and 38.5%), and the conditions of the gelation process. Well-known polyacrylamide gels were used to validate the methodology approach for the determination and analysis of elastic modulus (i.e., Young's modulus) distribution at the gel surface. We present elastic modulus distribution and topographical and stiffness maps for different chitosan hydrogels. For each chitosan hydrogel formulation, AFM analyses reveal a specific asymmetric elastic modulus distribution that constitutes a useful hallmark for chitosan hydrogel characterization. Our results regarding the local mechanical properties and the topography of chitosan hydrogels initiate new possibilities for an interpretation of the behavior of cells in contact with such soft materials.

Development of chitosan, gelatin and liposome film and analysis of its biocompatibility in vitro

A film of chitosan, gelatin and liposome has been designed for dermatological applications. Several adaptations were required throughout development to facilitate in vitro analysis, physicochemical characterization and biocompatibility evaluation. The final version of the film was characterized by differential scanning calorimetry, evaluation of swelling and scanning electron microscopy. The biocompatibility of the film was assessed by investigating cellular parameters of three types of human cells by direct contact or through films extracts: I) primary culture of adipose-derived mesenchymal stromal cells (ADCSs) and melanoma cell lines were used to test cell adhesion and morphology by direct cell culture on the material; II) ADSCs and immortalized keratinocytes were used in cell viability assay using different films extracts. The film showed physicochemical characteristics that favored cellular input, being suitable for in vitro analysis, which allowed its biocompatible characteristics such as the absence of toxicity to be verified without causing significant morphological changes in ADSCs and melanoma cell line. Altogether, these results suggest that the material has a potential application for drug delivery and promotion of skin tissue repair and is therefore worthwhile for further investigations using preclinical models to cover dermal lesions.

Growing a backbone - functional biomaterials and structures for intervertebral disc (IVD) repair and regeneration: challenges, innovations, and future directions

Back pain and associated maladies can account for an immense amount of healthcare cost and loss of productivity in the workplace. In particular, spine related injuries in the US affect upwards of 5.7 million people each year. The degenerative disc disease treatment almost always arises due to a clinical presentation of pain and/or discomfort. Preferred conservative treatment modalities include the use of non-steroidal anti-inflammatory medications, physical therapy, massage, acupuncture, chiropractic work, and dietary supplements like glucosamine and chondroitin. Artificial disc replacement, also known as total disc replacement, is a treatment alternative to spinal fusion. The goal of artificial disc prostheses is to replicate the normal biomechanics of the spine segment, thereby preventing further damage to neighboring sections. Artificial functional disc replacement through permanent metal and polymer-based components continues to evolve, but is far from recapitulating native disc structure and function, and suffers from the risk of unsuccessful tissue integration and device failure. Tissue engineering and regenerative medicine strategies combine novel material structures, bioactive factors and stem cells alone or in combination to repair and regenerate the IVD. These efforts are at very early stages and a more in-depth understanding of IVD metabolism and cellular environment will also lead to a clearer understanding of the native environment which the tissue engineering scaffold should mimic. The current review focusses on the strategies for a successful regenerative scaffold for IVD regeneration and the need for defining new materials, environments, and factors that are so finely tuned in the healthy human intervertebral disc in hopes of treating such a prevalent degenerative process.

Scaffolds for Wound Healing Applications

In order to overcome the shortcomings related to unspecific and partially efficient conventional wound dressings, impressive efforts are oriented in the development and evaluation of new and effective platforms for wound healing applications. In situ formed wound dressings provide several advantages, including proper adaptability for wound bed microstructure and architecture, facile application, patient compliance and enhanced therapeutic effects. Natural or synthetic, composite or hybrid biomaterials represent suitable candidates for accelerated wound healing, by providing proper air and water vapor permeability, structure for macro- and microcirculation, support for cellular migration and proliferation, protection against microbial invasion and external contamination. Besides being the most promising choice for wound care applications, polymeric biomaterials (either from natural or synthetic sources) may exhibit intrinsic wound healing properties. Several nanotechnology-derived biomaterials proved great potential for wound healing applications, including micro- and nanoparticulate systems, fibrous scaffolds, and hydrogels. The present paper comprises the most recent data on modern and performant strategies for effective wound healing.

Chitin and its derivatives: Structural properties and biomedical applications

Chitin, a polysaccharide that occurs abundantly in nature after cellulose, has attracted the interest of the scientific community due to its plenty of availability and low cost. Mostly, it is derived from the exoskeleton of insects and marine crustaceans. Often, it is insoluble in common solvents that limit its applications but its deacetylated product, named chitosan is found to be soluble in protonated aqueous medium and used widely in various biomedical fields. Indeed, the existence of the primary amino group on the backbone of chitosan provides it an important feature to modify it chemically into other derivatives easily. In the present review, we present the structural properties of chitin, and its derivatives and highlighted their biomedical implications including, tissue engineering, drug delivery, diagnosis, molecular imaging, antimicrobial activity, and wound healing. We further discussed the limitations and prospects of this versatile natural polysaccharide.

Chitinases and Chitinase-Like Proteins in Obstructive Lung Diseases - Current Concepts and Potential Applications

Chitinases, enzymes that cleave chitin’s chain to low molecular weight chitooligomers, are widely distributed in nature. Mammalian chitinases belong to the 18-glycosyl-hydrolase family and can be divided into two groups: true chitinases with enzymatic activity (AMCase and chitotriosidase) and chitinase-like proteins (CLPs) molecules which can bind to chitin or chitooligosaccharides but lack enzymatic activity (eg, YKL-40). Chitinases are thought to be part of an innate immunity against chitin-containing parasites and fungal infections. Both groups of these hydrolases are lately evaluated also as chemical mediators or biomarkers involved in airway inflammation and fibrosis. The aim of this article is to present the current knowledge on the potential role of human chitinases and CLPs in the pathogenesis, diagnosis, and course of obstructive lung diseases. We also assessed the potential role of chitinase and CLPs inhibitors as therapeutic targets in chronic obstructive pulmonary disease and asthma.

Label-free platform on pH-responsive chitosan: Adhesive heterogeneity for cancer stem-like cell isolation from A549 cells via integrin β4

Great efforts have been paid to develop methodologies for cancer stem-like cell (CSLC) isolation in anti-cancer research. The major obstacle lies in the lack of generic biomarkers for different cancer types and the requirement of complicated immuno-labeling procedures. The purpose of this study is to establish a label-free platform for CSLC isolation using pH-responsive chitosan. Based on the adhesive heterogeneity, 15.7 ± 1.9 % of human non-small cell lung cancer (NSCLC) cell line A549 detached from the chitosan substrate following medium pH elevation from 6.99 to 7.65 within 1 h. As a result, this subpopulation of cells with low adhesiveness exhibited superior CSLC hallmarks, including self-renewal, invasive and metastatic potential, therapeutic-resistance, colony formation in vitro, as well as nude mice xenograft in vivo for tumorigenesis, in comparison with their high-adhesive counterpart. Furthermore, integrin β4 is decisive in controlling CSLC detachment of NSCLC. Conclusively, this pH-dependent isolation provides new insights into biomaterial-based CSLC isolation.

Use of Ionic Liquids in Chitin Biorefinery: A Systematic Review

Lignocellulosic biomass biorefinery is the most extensively investigated biorefinery model. At the same time, chitin, structurally similar to cellulose and the second most abundant polymer on Earth, represents a unique chemical structure that allows the direct manufacture of nitrogen-containing building blocks and intermediates, a goal not accomplishable using lignocellulosic biomass. However, the recovery, dissolution, and treatment of chitin was fairly challenging until the polymer's easy dissolution in ionic liquids (salts that are liquid at room temperature) was discovered. In this systematic review, we highlight recent developments in the processing of chitin, with a particular emphasis placed on methods conducted with the help of ionic liquids used as solvents, co-solvents, or catalysts. Such use of ionic liquids in the field of chemical transformations of chitin not only allows for shorter times and less harsh reaction conditions, but also results in different outcomes and higher product yields when compared with reactions conducted in "traditional" manner. Valorization of biomass in general, and chitin in particular, is a key enabling strategy of the circular economy, due to the importance of the sustainable production of biomass-based goods and chemicals and full chain resource efficiency. Economics is driven by the production of high-value chemicals or chemical intermediates from various biomasses, and chitinous biomass is a valuable potential resource. A fundamental "paradigm shift" will radically change the balance of oil-based chemicals to biopolymer-based chemicals, and chitin valorization is a necessary step aimed toward its full market competitiveness and flexibility.

Repair strategies for traumatic spinal cord injury, with special emphasis on novel biomaterial-based approaches

As a part of the central nervous system (CNS), the adult mammalian spinal cord displays only very poor ability for self-repair in response to traumatic lesions, which mostly lead to more or less severe, life-long disability. While even adult CNS neurons have a certain plastic potential, their intrinsic regenerative capacity highly varies among different neuronal populations and in the end, regeneration is almost completely inhibited due to extrinsic factors such as glial scar and cystic cavity formation, excessive and persistent inflammation, presence of various inhibitory molecules, and absence of trophic support and of a growth-supportive extracellular matrix structure. In recent years, a number of experimental animal models have been developed to overcome these obstacles. Since all those studies based on a single approach have yielded only relatively modest functional recovery, it is now consensus that different therapeutic approaches will have to be combined to synergistically overcome the multiple barriers to CNS regeneration, especially in humans. In this review, we particularly emphasize the hope raised by the development of novel, implantable biomaterials that should favor the reconstruction of the damaged nervous tissue, and ultimately allow for functional recovery of sensorimotor functions. Since human spinal cord injury pathology depends on the vertebral level and the severity of the traumatic impact, and since the timing of application of the different therapeutic approaches appears very important, we argue that every case will necessitate individual evaluation, and specific adaptation of therapeutic strategies.

Spider Chitin. The biomimetic potential and applications of Caribena versicolor tubular chitin

Diverse fields of modern technology and biomedicine can benefit from the application of ready-to-use chitin-based scaffolds. In this work we show for the first time the applicability of tubular and porous chitin from Caribena versicolor spiders as a scaffold for the development of an effective CuO/Cu(OH)₂ catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AM), and as a scaffold for the tissue engineering of selected cells. The formation of CuO/Cu(OH)₂ phases on and within the chitinous tubes leads to a hybrid material with excellent catalytic performance with respect to the reduction of p-nitrophenol. On the other hand, experimental results provide for the first time strong evidence for the biocompatibility of spider chitin with different cell types, a human progenitor cell line (hPheo1), as well as cardiomyocytes differentiated from induced pluripotent stem cells (iPSC-CMs) that were cultured on a tube-like scaffold.

Design and evaluation of mesenchymal stem cells seeded chitosan/glycosaminoglycans quaternary hydrogel scaffolds for wound healing applications

The main goal of this study was the design, development and characterization of a chitosan based scaffolding substrate including three glycosaminoglycans and collagen to provide an optimal microenvironment for human mesemchymal stem cells isolated from adipose tissue (hMSCs). Chitosan scaffolds provide a moist wound environment which promotes healing and epidermal regeneration. Furthermore, the importance of extracellular molecules such as glycosaminoglycans in wound healing makes them essential ingredients in these types of formulations. The physical properties of hydrogels scaffolds and stability were investigated. The scaffolds were evaluated by structural and microscopic assays, as well as cell culture analyses. The hydrogel with best suitable properties was selected as candidate scaffold for hMSCs encapsulation. The viability of hMSCs remained above 75%, indicating good cell viability. The number of living hMSCs in the scaffold reached a steady state up to ~100% at days 5 and 7. Scanning electron microscopy showed irregular compartments with the presence of the hMSCs. These findings indicated that our hydrogel scaffold provided a suitable niche for cell viability which could be considered a promising candidate for further in vivo studies.