Effect of source and reaction conditions on the structure and rheological properties of gelatin methacryloyl

The purpose of this study was to systematically investigate how the origin of gelatin and the synthesis method influence the structural and rheological properties of gelatin methacryloyl (GelMA). Despite the widespread use of GelMA in biomedical research, direct and comparative analyses of the impact of gelatin source and synthetic approach remain limited, particularly regarding differences between conventional biphasic and alternative monophasic procedures. To address this gap, GelMA was synthesized from porcine, bovine, and fish gelatin using either the traditional two-phase method or a homogeneous single-phase strategy carried out in the polar aprotic solvent DMSO. The resulting polymers were extensively characterized in terms of degree of derivatization (DD), secondary structure and thermoresponsive gelation behavior. Our findings demonstrate that both the source of gelatin and the synthesis methodology exert profound effects on the properties of GelMA. While monophasic reactions allow for finer control over the DD, they simultaneously alter the rheological behavior of the polymer, likely as a consequence of disrupted chain–chain interactions. By clarifying these relationships, this work provides a rational framework for selecting gelatin sources and tailoring synthetic strategies according to the performance requirements of the final biomaterial. Overall, the insights gained here contribute to the optimization of GelMA for diverse pharmaceutical and biomedical applications, including 3D bioprinting and tissue engineering.