Self-healing behavior of silica-silk fibroin composite films with leaf surface microstructure

Abstract Silkworm silk fibroin (SF) is a promising next-generation material due to its self-healing capabilities. While this ability is often attributed to intrinsic non-covalent hydrogen bonds, the underlying mechanisms remain largely unexplored. This study investigates the influence of SF’s secondary structure and surface morphology on its self-healing behavior. We demonstrate that a higher β-sheet content inversely correlates with self-healing capacity. Consequently, incorporating SiO₂ nanoparticles, which disrupt ordered protein chain arrangements and hinder β-sheet formation, enhances self-healing. Furthermore, we examined the impact of surface microstructure, using the Syzygium samarangense leaf as a template. Our results show that structured surfaces increase the available surface area, providing more protein chains for bonding and improving self-healing properties. However, they can also promote β-sheet formation, which may counteract these benefits. This research highlights strategies for modulating the self-healing properties of SF through nanoparticle incorporation and surface microstructuring.