Behavior of primary human osteoblasts on trimmed and sandblasted Ti6Al4V surfaces functionalized with integrin avß3-selective cyclic RGD peptides

Abstract

It is well known that functionalization of surfaces with cell adhesive peptides mimicking the integrin binding motif of extracellular matrix proteins is a feasible approach to improve osseointegration of implant materials. Also, modi- fication of the surface properties of the material (e.g., rough- ness) strongly influences cell behavior. However, these two approaches are rarely studied together. This study addressed the hypothesis that the combination of peptide functionaliza- tion and surface roughness will have an enhancing effect on the adhesion process of osteoblasts. To test this hypothesis, a series of a v b 3-selective cyclic RGD peptides were prepared and immobilized on trimmed ( S a ¼ 0.74 l m, smooth) and sandblasted ( S a ¼ 3.24 l m, rough) Ti6Al4V disks. Effects of these surface modifications were evaluated with respect to integrin a v b 3-mediated adhesive capacity, cell morphology, and spreading of primary human osteoblasts. After 3 h of incubation, osteoblasts adhered more strongly on sand- blasted than on trimmed noncoated Ti6Al4V surfaces. Their attachment efficiency was further enhanced in the presence of RGD peptides. However, peptide functionalization had a relatively stronger impact on osteoblast attachment on trimmed surfaces compared with sandblasted surfaces. Cell morphology after 3 h of culture was exclusively altered by surface topography. RGD coating was critical for osteoblast spreading on both trimmed and sandblasted materials after 1 h of incubation but it showed almost negligible effects after 3 h. The results of this study provide evidence that the alli- ance of RGD coating and surface topography on Ti6Al4V pos- itively influences osteoblast adhesion and spreading, especially at very early adhesion times