BIOMIMETIC TREATMENTS OF TITANIUM SURFACE TO IMPROVE MSC ADHESION

Abstract

Aims: Surface modification of biomaterials to be used as scaffolds in tissue engineering is a promising method to improve device multi-functionality and biological properties. Biomimetic surface treatments, such as changes in nano-structure and attachment of biomolecular signals, enhance material bioactivity and affinity for specific cells. In this study the functionalization of a titanium surface with vitronectin-derived nonapeptide(HVP) and RGD peptides was investigated. Bone forming cells were used to analyse the role of each surface modification in the initial steps of cell adhesion process and then proliferation and differentiation.

Method: Smooth titanium samples were functionalized by different chemical treatments in order to obtain varying amount of peptide adhesion. Human marrow stro-mal cells (MSC) were seeded and cultured in osteogenic medium. Cell adhesion and morphology were assessed by fluorescence microscopy after 6 hours. Viability of MSC was quantified at 7 and 14 days from plating, proliferation was measured using DNA and total protein content, and osteoblast phenotype expression was assayed using alkaline phosphatase (ALP) and calcium content.

Results: The results showed that presence of HVP and RGD peptides improves cell morphology in early adhesion on surface, compared to control (titanium without peptides). Activity of ALP and Ca²⁺ content of (1:1000)HVP and RGD samples were higher than the other experimental surfaces with or without peptides, even if they did not reach the values of control cells on tissue culture polystyrene.

Discussion: Properties acquired with chemical treatments can improve titanium surfaces. These data provide information useful to develop biomimetic cell-friendly surfaces for bone engineering.