Silk inverse opals from template-directed β-sheet transformation of regenerated silk fibroin

We describe a novel and facile method for the fabrication of reconstituted silk monoliths with ordered interconnected air spheres based on intercalation and β-sheet transformation of regenerated silk fibroin solutions within the interstitial spaces of a sacrificial colloidal crystal template. The silk inverse opals are elastic and can withstand and recover from compressive loads of up to 112 MPa by reversible pore deformation. They also exhibit super-hydrophobicity with water droplet contact angles of up to 140° due to periodic nanoscale protrusions associated with the surface texture of the inverse opal architecture. These properties indicate that silk inverse opals could have potential applications as biocompatible elastic scaffolds, storage-release, barrier and self-cleaning materials, and in the design of load-responsive microfluidic devices.