Self-assembly of collagen fibrils on graphene oxide and their hybrid nanocomposite films

In order to explore the distribution, conformation and interaction of collagen on GO nanosheet surfaces, the mechanism of self-assembly of collagen was investigated in the presence of GO nanosheets. Atomic force microscopy (AFM) was employed to observe the conformation of self-assembled collagen fibrils on the GO nanosheets surfaces. The collagen concentration and incubation time mainly affect the size of the collagen fibrils while the pH of the dispersion determines the self-assembly sites of collagen fibrils on the GO nanosheets surfaces. This pH-dependent adsorption is attributed to the interfacial interactions between the tunable ionization of the collagen molecules and the amphiphilic GO nanosheets. Vacuum-assisted self-assembly technology confirmed that GO nanosheets can direct the self-assembly of collagen molecules and form nacre-like nanocomposites. The GO/collagen nanocomposite films combine the remarkable properties of GO nanosheets and collagen to form functional nanocomposites with well-ordered hierarchical structures. Further, strong interfacial interactions between GO nanosheets with collagen fibrils result in enhanced mechanical properties and biocompatibility of nanocomposite films, which is conducive to enhance the neuronal differentiation of SH-SY5Y cells. Overall, this work provides fresh insight into the interactions between GO and collagen, which is essential for the design and manufacture of bioinspired nanocomposites with tailored mechanical properties.