The effect of VEGF functionalization of titanium on endothelial cells in vitro.

One of the key challenges in bone healing and regeneration is the engineering of an implant with surface properties that can enhance revascularization to meet the metabolic demands of recovery. Successful implant integration into the surrounding tissue is highly dependent on the crucial role of blood supply in driving bone repair and development. Therapeutic application of vascular endothelial growth factor (VEGF) is a promising approach to enhance blood supply and healing through revascularization around an engineered implant in a regulated manner. In this in vitro study, we investigated the effects of immobilized VEGF on titanium alloy substrates coated with thin adherent polydopamine film. X-ray photoelectron spectroscopy (XPS) was used to determine the chemical composition of the surfaces at various stages of surface functionalization to verify the successful deposition of polydopamine and VEGF on the metal surface. Surface topography was evaluated from the surface profile determined by atomic force microscopy (AFM). The functionalized surfaces showed a significant increase in human dermal microvascular endothelial cells (HDMECs) attachment, viability and proliferation compared to the pristine substrate. Furthermore the immobilized VEGF was able to induce the differentiation of human mesenchymal stem cells (hMSCs) into endothelial cells. Therefore utilizing the reactivity of polydopamine films to immobilize VEGF onto metal substrates may provide a promising approach for application in situations where revascularization around implants would be beneficial in improving bone healing and implant integration.