Development of bio-hybrid piezoresistive nanocomposites using silk-elastin protein copolymers

Recombinant silk-elastin-like protein (SELP)/carbon nanotubes (CNTs) nanocomposite films with different amounts of CNTs (1, 3 and 6 wt%) were prepared by solvent casting. The produced films were stabilized by exposure to methanol that induces an increase of the beta-structure content. The CNTs were homogeneously distributed into the SELP matrix and did not induce significant alterations into its chemical structure. The incorporation of CNTs also increased the thermal stability of the films. Further, the incorporation of 1 wt% of CNTs greatly improved the mechanical properties of the SELP matrix leading to a 6-fold increase in strain-to-failure and to increase the ultimate tensile strength with minor differences in modulus of elasticity. The nanocomposites exhibited a good linearity between deformation and electrical resistance variation with electrical conductivity increasing with the nanofiller content up to 0.8 S m(-1). Finally, the produced nanocomposites were non-cytotoxic indicating their suitability for biomedical applications.