Fabrication and characterisation of protein fibril–elastomer composites

Protein fibrils are emerging as a novel class of functional bionanomaterials. In this paper we make use of their rigidity by combining lysozyme fibrils with a silicone elastomer and demonstrating that at a filling ratio of 10%, the protein fibril composite is at minimum 2 times stiffer than a CNT elastomeric composite of the same filling ratio. We also show that when the elastomer is patterned such that the lysozyme fibrils can be spatially modulated within the elastomer, anisotropic moduli varying by a factor of 2 is produced. By using shear mixing as the fabrication process, the modulus of a 2 wt.% insulin fibril composite is equivalent to a CNT composite with the same filling ratio. In conclusion, we have presented the fabrication and mechanical characterisation of a class of elastomer/protein fibril composite material.