▎ 摘　　要

Osteoprogenitor cells, known as preosteoblasts, that arise from mesenchymal stem cells in the bone marrow are types of cells that work in the growth or repair of bones. These cells possess the prominent potential to differentiate toward the osteogenic lineage, and therefore offer promising opportunities for bone tissue engineering and regenerative therapy. However, to fully exploit the application of osteoprogenitor cells in bone regeneration, it is critical to develop biochemical, physical or pharmaceutical factors that can precisely control their osteogenic differentiation. In this study, we hypothesized that reduced graphene oxide (rGO) and hydroxyapatite (HAp) composites could synergistically enhance the osteogenic differentiation of preosteoblasts. Without interference with the proliferation of MC3T3-E1 preosteoblasts, rGO/HAp composites synergistically enhanced the osteogenic differentiation of the preosteoblasts, which had been confirmed by determining alkaline phosphatase activity and mineralization of calcium and phosphate as early and late stage markers of osteogenic differentiation. This osteogenic activity mediated by rGO/HAp composites was further accelerated under osteogenic culture conditions. It is suggested that rGO/HAp hybrid composites can serve as biocompatible, transferable, and implantable scaffolds for bone regeneration because these graphene-based composite materials have the potential to promote spontaneous osteogenesis in the absence of any osteogenic factors. (C) 2015 Elsevier Ltd. All rights reserved.