Rational Design of Spider Silk-Based Biomaterials

Nature has evolved a variety of complex yet elegant and functional biomaterials, providing a formidable source of inspiration for scientists. For example, the silk, elastin, resilin and collagen etc. are fantastic biomaterials with sophisticated micro- to macro-scale structures and properties for specific applications. However, natural biomaterials as harvested are often inconsistent in batch composition and across sources, resulting in an inability to precisely dictate the properties of most natural materials. Recent developments in synthetic biology and metabolic engineering offer an alternative to recapitulate and even tune the properties of native biomaterials. Here we show that biomimetic design and production of long, highly repetitive protein of spider silk that is ultimately spun into a strong fiber with native-like mechanical properties. We also show that the conserved C-terminal domain of spider silk self-assembles into dual thermosensitive hydrogels, thus offering a functional module for the design and construction of novel protein hydrogels. Furthermore, we demonstrate the formation of hydrogels with multiple sensitivity and tunable properties when the consensus repeats of spider silk and other functional modules of natural biomaterials are genetically fused to the C-terminal domain of spider silk. The diverse forms and tunable properties of newly designed spider silk-based biomaterials reflect the power of synthetic biology in modular design of protein-based polymers at the DNA, protein, and material levels (this project was supported by the National Natural Science Foundation of China Grant No. 31470216 and the Shanghai Pujiang Program Grant No. 14PJ1405200).