Engineering of silk proteins for materials applications

Silk combines biological properties, such as non-toxicity and biodegradability, with physico-chemical ones, for example, mechanical strength. Base on molecular engineering, nowadays also new non-silk functions can be implemented in silk materials. Driven by rational design and ingenuity, innovative recombinant silk proteins can be designed with a plethora of functions to address biomedical and technological challenges. Herein, we review advances in engineering silk proteins for tailored functions at the molecular level. Insights are provided in genetically engineered silk fusions with functional or other structural proteins and in hybrids with DNA. In such novel materials, self-assembly features of silk are combined and utilized with expedient properties of the additional components. The availability of functionalized silk materials is opening routes toward a whole set of novel applications not achievable with natural silk or other polymers.