Biomaterial Bilayers with Gelatin and Agar as Skin Substitutes

This study evaluated five gelatin-, agar-, and bilayer-based biomaterial formulations as low-cost candidates for skin-substitute applications. Gelatin, agar, gelatin–silicon dioxide, agar–silicon dioxide, and gelatin–agar formulations were assessed using seven-day weight-loss measurements, three-point bending tests, and qualitative evaluations of flexibility and surface stability. The gelatin–agar bilayer demonstrated the lowest mean weight loss (7.3%) and maintained the greatest flexibility and surface stability, but exhibited the lowest mechanical strength. Agar-based formulations showed the highest resistance to bending but became increasingly rigid and brittle during storage. Statistical analyses indicated that the base material significantly affected peak load and relative flexural performance, whereas adding silicon dioxide did not significantly improve degradation resistance or mechanical performance. The gelatin–agar bilayer provided the most balanced physical performance, although further optimization is required to improve its mechanical strength. Future studies should standardize specimen dimensions and evaluate biocompatibility, physiological degradation, and wound-healing performance.