Mechanical, Thermal, and Rheological Properties of Fish–Porcine Gelatin Microparticle Composites for Advanced 3D Biofabrication

Driven by the increasing need for the biofabrication of complex hydrogels, this work introduces a class of fish–porcine composite hydrogels that combine rapid, tunable photo-cross-linking with microparticle reinforcement for advanced 3D printing. Here, precross-linked porcine gelatin (methacrylated porcine gelatin, MPG) microparticles are incorporated into a methacrylated fish gelatin (MFG) matrix to produce robust yet easily processable hydrogels. Nuclear magnetic resonance (NMR) confirmed the degree of methacrylation, while scanning electron microscopy (SEM) revealed the hierarchical porosity vital for tissue integration. Detailed Mastersizer measurements characterized the size distributions of the MPG microparticles, and rheological tests demonstrated the composite hydrogels’ strong shear-thinning behavior, an essential trait for extrusion-based and embedded 3D printing. Thermal (TGA, DSC) and mechanical (compression) analyses show that the microparticle-reinforced hydrogels achieve improved thermal stability, adjustable mass swelling ratio, and customizable compressive moduli. As a proof of concept, these composites are validated in digital light processing (DLP) printing of microfluidic constructs and as a support bath for embedded printing of complex geometries. This platform provides a unique synergy of easy UV cross-linkability, tunable mechanical features, and 3D printing versatility. This advancement underscores the potential of these materials as a foundational platform in tissue engineering, opening new avenues for creating complex, biocompatible structures with customizable properties.