Graphene oxide nanolayers as nanoparticle anchors on biomaterial surfaces with nanostructures and charge balance for bone regeneration

Graphene oxide (GO) is a carbon-based nanomaterial with high surface area and abundant functional groups, providing various sites for binding and immobilization of growth factor vehicles. This study used GO nanolayer as an anchor for the immobilization of bone morphogenetic protein-2 (BMP-2)-encapsulated bovine serum albumin nanoparticles (NPs) on the hydroxyapatite (HA) and tricalcium phosphate (TCP) scaffolds by electrostatic interaction between the positive charges of the NPs and negative charges of GO. GO nanolayers prevented the rapid degradation of TCP scaffolds. Moreover, GO nanolayers promoted NP adsorption on these scaffolds, and realized BMP-2 sustained release. NPs endowed the scaffold surfaces with a nanostructure similar to that of the extracellular matrix (ECM), improving bone marrow stromal cell (BMSC) attachment. Furthermore, the positive charged NPs and negative charged GO nanolayers constructed a charge-balanced surface on the scaffolds, enhancing BMSC proliferation. The nanostructure, charge balance and BMP-2 sustained release capability synergistically improved BMSC differentiation and bone regeneration. In summary, GO is a potential candidate to modify biomaterial surfaces as an anchor for efficient immobilization of growth factor vehicles. (C) 2017 Wiley Periodicals, Inc.