Thermoplastic moulding of regenerated silk.

Chengchen Guo, Chunmei Li, Hiep V Vu, Philip Hanna, Aron Lechtig, Yimin Qiu, Xuan Mu, Shengjie Ling, Ara Nazarian, Samuel J Lin, David L Kaplan

Nature materials 2020 Jan

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Early insights into the unique structure and properties of native silk suggested that β-sheet nanocrystallites in silk would degrade prior to melting when subjected to thermal processing. Since then, canonical approaches for fabricating silk-based materials typically involve solution-derived processing methods, which have inherent limitations with respect to silk protein solubility and stability in solution, and time and cost efficiency. Here we report a thermal processing method for the direct solid-state moulding of regenerated silk into bulk 'parts' or devices with tunable mechanical properties. At elevated temperature and pressure, regenerated amorphous silk nanomaterials with ultralow β-sheet content undergo thermal fusion via molecular rearrangement and self-assembly assisted by bound water to form a robust bulk material that retains biocompatibility, degradability and machinability. This technique reverses presumptions about the limitations of direct thermal processing of silk into a wide range of new material formats and composite materials with tailored properties and functionalities.

Citation

Chengchen Guo, Chunmei Li, Hiep V Vu, Philip Hanna, Aron Lechtig, Yimin Qiu, Xuan Mu, Shengjie Ling, Ara Nazarian, Samuel J Lin, David L Kaplan. Thermoplastic moulding of regenerated silk. Nature materials. 2020 Jan;19(1):102-108