Reverse Engineering Spider Silk by Disassembly and Assembly

Spider silk combines outstanding strength and toughness with biocompatibility and light weight, thus outperforming some of the best synthetic materials. Despite extensive research, fully comprehensive experimental evidence of the formation and morphology of the internal structure of spider silk is still limited and controversially discussed. We used mechanical exfoliation to completely exfoliate spider silk, which showed that the silk of the golden orb-weaver is entirely composed of parallel, 10 nm-diameter nanofibrils featuring a particular morphology. This process allowed us to mass-produce spider silk nanofibrils for the first time. Furthermore, we show that the silk protein possesses an intrinsic mechanism to form nanofibrils of the same morphology via shear-induced molecular self-assembly, which can be easily triggered <i>in vitro</i>. By altering the physical and chemical environment of this process, we were able to study the conditions of formation of spider silk and to reveal both physical and chemical triggers for assembly at molecular scales. This knowledge will help understand the fundamentals of this exceptional material, paving the way for the realization of silk-inspired high-performance materials.