Fabrication of Freestanding Hybrid Membranes. The hybrid films investigated in this study were fabricated from dispersions of graphene oxide (GO), titania nanorods (TNRs), and silk fibroin (SF) via layer-by-layer spin-coating (LbL-SC). Exemplary transmission electron microscopy (TEM) and atomic force microscopy (AFM) images of the TNRs and GO flakes are shown in the Supporting Information, Section S1. The multilayered structure of the hybrid films is schematically shown in Figure .