MECHANICAL PROPERTIES OF SILK FIBROIN AND ITS REINFORCEMENT BY GRAPHENE BASED ON MOLECULAR DYNAMIC SIMULATIONS
Yuan Cheng, Yong-Wei Zhang
Institute of High Performance Computing, A*STAR, Singapore
Key Words: Silk fibroin, Graphene, Molecular dynamics simulation, Mechanical property.
Silk fibroin has attracted great attention due to its superior mechanical properties such as high stretchability and strength, biocompatibility, as well as its versatile biodegradability and processability.1 They can be made into various morphologies such as sponges, hydrogels, films, mats and particles, facilitate their wide applications as medical textiles, surgical sutures, tissue engineering scaffolds, drug carriers, optics, sensors, etc. Great efforts are demanded in order to understand and further enhance the mechanical properties of silk fibroin. In this study, intensive molecular dynamics simulations were carried out on silk crystalline and the interactions between graphene substrate and model peptides with different sizes extracted from different domains of silk fibroin.2,3 The simulation result on secondary structure component of peptides agrees well with the experimental data. Our study shows that graphene substrate has different impact on structural properties of different domains of silk fibroin. Tensile tests were also carried out on representative peptides to measure the mechanical properties of the peptides related to strength and resilience. It was found that the stregnth of the peptides are enhanced upon adsorption to the graphene surface. These results provide in-depth understandings in molecular structure-mechanical property correlation of protein upon adsorption to the substrate, and will serve as a guideline to future design of bio-inspired materials.