Speaker
Description
Introduction
Skin regeneration, especially in large wounds, remains a clinical challenge due to the limited healing capacity of human skin.1 In situ bioprinting enables targeted tissue reconstruction by directly depositing bioinks onto injury sites, supporting the development of personalized regenerative therapies.2 For effective skin regeneration through in situ bioprinting, bioinks must rapidly form stable structures while preserving cell viability.3 However, conventional bioinks for in-situ bioprintng often require post-crosslinking via UV light or chemical agents, inducing cytotoxicity.4
In this study, we developed a thermosensitive bioink by combining porcine skin-derived decellularized extracellular matrix (SdECM) and hexanoyl glycol chitosan (HGC), where the SdECM is expected to provide bioactive signals to enhance cell affinity. The bioink enabled cell encapsulation at low temperatures and rapidly gelation at physiological temperature without additional crosslinker.
Method
HGC was synthesized by N-hexanoylation of glycol chitosan.5 The synthesized HGC was blended with varying amounts of SdECM powder in saline, and the mixtures were stirred overnight. The sol-gel transition temperature, viscosity, modulus of bioink were measured using a rotational rheometer. The printability of the bioink was evaluated through line and circle pattern printing. The biocompatibility of the bioink was assessed by Live/Dead staining and CCK-8 assay. In vivo experiment was conducted by directly printing the bioink on skin wounds constructed on the backs of nude mice.
Result
The sol–gel transition temperature of HGC and HGC/SdECM bioinks decreased from 35 °C to 30 °C with increasing SdECM content, suggesting that enhanced physical crosslinking contributed to improved mechanical properties. The bioinks exhibited shear-thinning and thixotropic behaviors, confirming its suitability for 3D bioprinting applications. Printing tests identified the printable range of each bioink under ambient conditions, with the HGC/SdECM1.5 group exhibiting the broadest range. Live/Dead staining indicated high cell viability across all groups. CCK-8 assay result revealed that higher SdECM content in the bioink was associated with significantly enhanced cell proliferation. In vivo experiments demonstrated that the bioink could be directly applied via 3D printing to wound sites with site-specific deposition, and confirmed its effectiveness in promoting skin tissue regeneration.
Discussion
The thermosensitive HGC/SdECM bioink exhibits biocompatibility and printability, along with structural stability without additional crosslinking agents. The results confirm the bioink’s potential for skin regeneration through in situ bioprinting and its applicability to other tissues, providing a foundation for advanced therapeutic solutions.
Reference
1. Albanna, M. et al. In situ bioprinting of autologous skin cells accelerates wound healing of extensive excisional full-thickness wounds. Sci. Rep. 9, 1856 (2019)
2. Hu, C. et al. In situ bioprinting: Tailored printing strategies for regenerative medicine. Int. J. Bioprint. 10, 3366 (2024)
3. Douglas, A. et al. Bioprinting-by-design of hydrogel-based biomaterials for in situ skin tissue engineering. Gels 11, 110 (2025).
4. GhavamiNejad, A. et al. Crosslinking strategies for 3D bioprinting of polymeric hydrogels. Small 16, 2002931 (2020).
5. Cho, I. S. et al. Thermosensitive hexanoyl glycol chitosan-based ocular delivery system for glaucoma therapy. Acta Biomater. 39, 124–132 (2016).
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