Insights into Nanomechanical Behavior and Molecular Mechanisms in Bombyx Mori Silk Fibroin in Saline Environment Using Molecular Dynamics Analysis

M Patel and DK Dubey and SP Singh, MACROMOLECULAR RESEARCH, 29, 694-712 (2021).

DOI: 10.1007/s13233-021-9084-6

Bombyx mori silk fibroin (B. mori SF) is a prospective and promising biomaterial being investigated by the scientific research fraternity around the world for its biomedical applications such as tissue engineered grafts. This consideration of silk fibroin as biomaterial is possible given its suitable mechanical and biological properties. Mechanical properties and behavior of a biopolymer or biomaterial are greatly affected by the chemical environment surrounding it. To assess the suitability of B. mori SF for application as tissue scaffold and graft, it is vitally essential to understand the influence of saline environment (such as provided by extracellular fluids in the physiological conditions and during pre and post-treatments of the fiber or scaffold) on its mechanical behavior and molecular mechanics. Current study investigates the tensile mechanical behavior of B. mori SF under varying saline environments (0 to 4.5 M) using molecular dynamics (MD) simulations. Elastic modulus values of 7 to 20 GPa and peak stress values of 350 to 750 MPa are computed for the two models for 0 to 4.5 M saline environments. Examining the obtained results show that peptide salt interactions are primarily contributing to the enhanced mechanical response of B. mori SF nanostructure. In addition, formation of ionic bridges between the salt ions present in saline environment and peptide strands, facilitating the enhanced mechanical response, are also observed. Ultimately, it is envisioned that the molecular deformation mechanisms and mechanistic understanding extracted from current study can be informative towards future investigation of silk-based biomaterials.

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