Strong, ductile and lightweight bionanocomposites constructed by bioinspired hierarchical assembly

Abstract

Abstract Strong, ductile and lightweight materials (SDLMs) are pursued in a wide range of fields, such as biomedicine and structural engineering. However, it remains a significant challenge to experimentally synthesize such structural and mechanical optimized materials. Here, we integrate multiscale assembly and in vitro biomineralization to construct SDLMs that made of silk nanofibril (SNF), hydroxyapatite nanocrystal (HAP), and chitin nanofibril (CNF). This bioinspired approach can control the structure and mechanics of the materials from nano-to macro-scale. The resultant SDLMs achieved enhanced compression strength with a value reached up to 316 ± 74 MPa, which is higher than that of most natural materials (e.g., bone and nacre) and artificial nanocomposites (e.g., carbon nanomaterial-reinforced polymer composites). The extraordinary mechanical strength, together with outstanding biocompatibility, allow SNF/HAP:CNF SDLMs to be used in various emerging fields, such as bone-associated tissue engineering and water-treatment materials. Moreover, this design and assembly strategy can be transferred to another biomimetic system, providing a useful guideline for SDLM designs.