Impact of ethylene oxide sterilization cycle condition on the physicochemical properties, printability and cytotoxicity of gelatin methacrylamide-based bioink formulation

Abstract

Gelatin methacrylamide (GelMA) is a widely used bioink for three-dimensional (3D) bioprinting owing to its tunable mechanical properties and excellent biocompatibility. Sterilization is an essential terminal step in both biomedical device manufacturing and the preparation of bioinks for 3D bioprinting. Ethylene oxide (EtO) sterilization is a widely used method for sterilizing medical devices. However, its effects on biomaterials such as GelMA must be evaluated to ensure effective sterilization while preserving the physicochemical properties required for bioink performance. In this study, the effects of EtO sterilization at two temperatures (37 °C and 55 °C) on a GelMA bioink containing an antioxidant (GelMA-AO) were investigated with respect to its structural integrity, crosslinking efficiency, and three-dimensional (3D) printability. Changes in chemical functional groups, rheological properties, printability, crosslinking efficiency, compressive strength, and cytotoxicity were evaluated before and after EtO sterilization. The rheological analysis showed that sterilization at 55 °C altered the viscosity of the GelMA-AO formulation. In contrast, sterilization at 37 °C preserved the chemical, rheological, and mechanical properties of the GelMA-AO bioink while ensuring sterility and non-cytotoxicity. These findings demonstrate the importance of carefully optimizing EtO sterilization conditions to maintain the performance and functionality of GelMA-based bioink formulations for 3D bioprinting applications.