Chemical, thermal, time, and enzymatic stability of silk materials with silk i structure

Meihui Zhao, Zhenzhen Qi, Xiaosheng Tao, Chad Newkirk, Xiao Hu, Shenzhou Lu

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The crystalline structure of silk fibroin Silk I is generally considered to be a metastable structure; however, there is no definite conclusion under what circumstances this crystalline structure is stable or the crystal form will change. In this study, silk fibroin solution was prepared from B. Mori silkworm cocoons, and a combined method of freeze-crystallization and freeze-drying at different temperatures was used to obtain stable Silk I crystalline material and uncrystallized silk material, respectively. Different concentrations of methanol and ethanol were used to soak the two materials with different time periods to investigate the effect of immersion treatments on the crystalline structure of silk fibroin materials. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman scattering spectroscopy (Raman), Scanning electron microscope (SEM), and Thermogravimetric analysis (TGA) were used to characterize the structure of silk fibroin before and after the treatments. The results showed that, after immersion treatments, uncrystallized silk fibroin material with random coil structure was transformed into Silk II crystal structure, while the silk material with dominated Silk I crystal structure showed good long-term stability without obvious transition to Silk II crystal structure. α-chymotrypsin biodegradation study showed that the crystalline structure of silk fibroin Silk I materials is enzymatically degradable with a much lower rate compared to uncrystallized silk materials. The crystalline structure of Silk I materials demonstrate a good long-term stability, endurance to alcohol sterilization without structural changes, and can be applied to many emerging fields, such as biomedical materials, sustainable materials, and biosensors.

    Original languageEnglish (US)
    Article number4136
    JournalInternational Journal of Molecular Sciences
    Volume22
    Issue number8
    DOIs
    StatePublished - Apr 2 2021

    All Science Journal Classification (ASJC) codes

    • Catalysis
    • Molecular Biology
    • Spectroscopy
    • Computer Science Applications
    • Physical and Theoretical Chemistry
    • Organic Chemistry
    • Inorganic Chemistry

    Fingerprint Dive into the research topics of 'Chemical, thermal, time, and enzymatic stability of silk materials with silk i structure'. Together they form a unique fingerprint.

    Cite this