3D-Printed Fish Gelatin–Xanthan Gum Hydrogel with Myogenic Differentiation toward Skeletal Muscle Loss Repair

Fish gelatin for 3D extrusion printing applications presents inherent challenges, primarily due to its relatively low mechanical strength. Despite its beneficial properties, including high bioactivity, suppressed inflammation, and cost-effectiveness, uninterrupted extrusion at constant pressure has been limited without the use of synthetic materials or functionalization. The incorporation of plasticizers and thickening agents/stabilizers, such as xanthan gum, can enhance continuous extrusion, maintain shape fidelity, and reduce gravitational flow before complete cross-linking. Sustainable biomaterial inks comprising fish gelatin (FG) from Catla catla scales, xanthan gum (XG), and microbial transglutaminase (mTG) have been explored for the fabrication of tailorable, customized porous hydrogels for myogenic tissue engineering. Characterizations indicated multiple layers with high cross-linking density (72 ± 3%) and water absorption capacity. Hydrogels exhibited cell proliferation and aligned growth along the struts. A myogenic differentiation study using C2C12 and human amniotic membrane stem cells (HAMSCs) demonstrated the formation of aligned myotubes and myoblast alignment, respectively. The CAM assay revealed enhanced angiogenesis and microvascular growth along the filaments. Hydrogels facilitated functional skeletal muscle regeneration in Wistar rat models of volumetric muscle loss (VML). Improved regeneration was evidenced by increased expression of myosin IIb and Myh7, as determined by immunohistochemistry (IHC), and late myogenic markers, as revealed by quantitative real-time PCR (qRT-PCR). Fish gelatin hydrogels show promise as a sustainable and economical method for enhancing muscle regeneration by delivering bioactive signals at the VML site.