Adipose-derived stem cell spheroid-laden microbial transglutaminase cross-linked gelatin hydrogel for treating diabetic periodontal wounds and craniofacial defects.

BACKGROUND: Diabetes mellitus deteriorates the destruction and impairs the healing of periodontal wounds and craniofacial defects. This study is to evaluate the potential of self-assembled adipose-derived stem cell spheroids (ADsp) in microbial transglutaminase cross-linked gelatin hydrogel (mTG) for treating diabetic periodontal wounds and craniofacial defects. METHODS: Human adipose-derived stem cells (ADSCs) were isolated by lipoaspiration, pluripotent genes and trilineage differentiation were examined, and the maintenance of ADsp properties in mTG was verified. Oral mucosal wounds and calvarial osseous defects were created in diabetic rats. Gross observation, histologic evaluation, and immunohistochemistry for proliferating cells and keratinization were conducted in the mucosal wounds within 4-28 days. Micro-CT imaging, histologic evaluation, and immunohistochemistry for proliferating cells and osteogenic differentiation were conducted in the osseous defects at 7 and 28 days. RESULTS: ADSCs expressed pluripotent genes and were capable of trilineage differentiation. ADsp retained morphology and stemness in mTG. In diabetic mucosal wounds, wound closure, epithelization, and keratinization were accelerated in those with ADsp and ADsp-mTG. In diabetic osseous defects, osteogenic differentiation markers were evidently expressed, cell proliferation was promoted from day 7, and bone formation was significantly promoted at day 28 in those with osteogenically pretreated ADsp-mTG. CONCLUSIONS: ADsp-mTG accelerated diabetic oral mucosal wound healing, and osteogenically pretreated ADsp-mTG promoted diabetic osseous defect regeneration, proving that ADsp-mTG facilitated diabetic periodontal wound healing and craniofacial osseous defect regeneration.

A hemostatic keratin/alginate hydrogel scaffold with methylene blue mediated antimicrobial photodynamic therapy.

Uncontrollable bleeding and infection are two of the most common causes of trauma-related death. Yet, developing safe materials with high hemostatic and antibacterial effectiveness remains a challenge. Keratin-based biomaterials have been reported to exhibit the functions of enhancing platelet binding and activating and facilitating fibrinogen polymerization. In this study, we designed a hemostatic material with good biodegradability, biocompatibility, hemostatic ability, and antibacterial function to solve the shortcomings of common hemostatic materials. Methylene blue-loaded keratin/alginate composite scaffolds were prepared by the freeze-gelation method. The composite scaffolds exhibited over 1600% liquid absorption, well-interconnected pores, good biocompatibility, and biodegradability. We find that the keratin/alginate composite scaffolds' synergistic action may significantly reduce hemostasis time. To prevent infection, the drug-loaded scaffolds generated high burst release by absorbing wound exudate in the early stages of wound healing. The results obtained by the antimicrobial photoinactivation assay in vitro suggest that an antimicrobial photodynamic effect might be triggered, thereby preventing the fast growth of colonies.

Design and Synthesis of Stem Cell-Laden Keratin/Glycol Chitosan Methacrylate Bioinks for 3D Bioprinting.

With the advancements in tissue engineering and three-dimensional (3D) bioprinting, physiologically relevant three-dimensional structures with suitable mechanical and bioactive properties that mimic the biological tissue can be designed and fabricated. However, the available bioinks are less than demanded. In this research, the readily available biomass sources, keratin and glycol chitosan, were selected to develop a UV-curable hydrogel that is feasible for the 3D bioprinting process. Keratin methacrylate and glycol chitosan methacrylate were synthesized, and a hybrid bioink was created by combining this protein-polysaccharide cross-linked hydrogel. While human hair keratin could provide biological functions, the other composition, glycol chitosan, could further enhance the mechanical strength of the construct. The mechanical properties, degradation profile, swelling behavior, cell viability, and proliferation were investigated with various ratios of keratin methacrylate to glycol chitosan methacrylate. The composition of 2% (w/v) keratin methacrylate and 2% (w/v) chitosan methacrylate showed a significantly higher cell number and swelling percentage than other compositions and was designated as the bioink for 3D printing afterward. The feasibility of stem cell loading in the selected formula was examined with an extrusion-based bioprinter. The cells and spheroids can be successfully printed with the synthesized bioink into a specific shape and cultured. This work provides a potential option for bioinks and delivers insights into personalization research on stem cell-laden biofabricated hydrogels in the future.