ABSTRACT
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.
Subject(s)
Bioprinting , Chitosan , Bioprinting/methods , Humans , Hydrogels/chemistry , Keratins , Methacrylates , Printing, Three-Dimensional , Stem Cells , Tissue Engineering/methods , Tissue Scaffolds/chemistryABSTRACT
Engineered skin that can facilitate tissue repair has been a great advance in the field of wound healing. A well-designed dressing material together with active biological cues such as cells or growth factors can overcome the limitation of using auto-grafts from patients. Recently, many studies showed that human adipose-derived stem cells (hASCs) can be used to promote wound healing and skin tissue engineering. hASCs have already been widely applied for clinical trials. hASCs can be harvested abundantly because they can be easily isolated from fat tissue known as the stromal vascular fraction (SVF). On the other hand, increasing studies have proven that cells from spheroids can better simulate the biological microenvironment and can enhance the expression of stemness markers. However, a three-dimensional (3D) scaffold that can harbor implanted cells and can serve as a skin-repaired substitute still suffers from deficiency. In this study, we applied a gelatin/microbial transglutaminase (mTG) hydrogel to encapsulate hASC spheroids to evaluate the performance of 3D cells on skin wound healing. The results showed that the hydrogel is not toxic to the wound and that cell spheroids have significantly improved wound healing compared to cell suspension encapsulated in the hydrogel. Additionally, a hydrogel with cell spheroids was much more effective than other groups in angiogenesis since the cell spheroid has the possibility of cell-cell signaling to promote vascular generation.
ABSTRACT
OBJECTIVE: To develop a dressing with desired antibacterial activity, good water maintaining ability and mechanical properties for wound healing and skin regeneration. METHODS: The chitosan with different concentrations were added in keratin solution to form porous keratin/chitosan (KCS) scaffolds. The morphological characteristics, chemical composition, wettability, porosity, swelling ratio and degradation of the scaffolds were evaluated. The antibacterial activity was tested by using S. aureus and E. coli suspension for 2 h. And L929 fibroblast cells culture was used to evaluate the cytotoxicity of the KCS scaffolds. RESULTS: The adding of chitosan could increase the hydrophobicity, decrease porosity, swelling ratio and degradation rate of the KCS porous scaffolds. Mechanical properties of KCS scaffolds could be enhanced and well adjusted by chitosan. KCS scaffolds could obviously decrease bacteria number. The proliferation of fibroblast cells in porous KCS patch increased firstly and then decreased with the increase of chitosan concentration. It was appropriate to add 400 µg/mL chitosan to form porous KCS scaffold for achieving best cell attachment and proliferation compared with other samples. CONCLUSION: The porous KCS scaffold may be used as implanted scaffold materials for promoting wound healing and skin regeneration.
