Biocompatibility assessment of SilkMA-Gelatin ink tuned for 3D extrusion bioprinting

3D bioprinting applications have led to the development of multifunctional scaffolds that are biocompatible, overcoming shear stress to provide structural integrity. We report the isolation of silk fibroin (SF) using calcium chloride (CaCl ₂ ), which was further developed into an ink comprising silkMA and gelatin, demonstrating effective cytocompatibility and biocompatibility when 3D printed using an extrusion-based 3D bioprinter. Rheological characterization of SilkMA-Gelatin showed an improved viscosity and printability of the formulation as compared to an unmodified silk-gelatin composition. SilkMA-gelatin was bioprinted with NIH3T3 cells and demonstrated enhanced viability and proliferation, highlighting its cytocompatibility and ability to support a favourable 3D microenvironment. In vivo biocompatibility of the 3D bioprinted SilkMA-Gelatin was evaluated in Wistar rats, where 3D printed scaffolds maintained structural stability for up to 1 month, with no inflammatory response, progressive cell infiltration, and re-epithelialization. Serum biochemistry analysis, including ALP, ALT, LDH, and Urea (BUN), remained within normal physiological ranges, further confirming systemic safety. Based on the findings, the optimized SilkMA-gelatin ink proves to be highly effective in fabricating cell-laden structures that are stable, exhibit enhanced cytocompatibility and biocompatibility, and offer promising potential for advanced tissue regeneration applications.