AVS 46th International Symposium
    Biomaterial Interfaces Group Thursday Sessions
       Session BI-ThM

Paper BI-ThM5
Osteoblast Behavior on Surfaces with Varied RGD Peptide Surface Concentrations Prepared Using Gold-Thiol Self-Assembly

Thursday, October 28, 1999, 9:40 am, Room 613/614

Session: Biomineralization
Presenter: G.D. Moodie, Brown University
Authors: G.D. Moodie, Brown University
D.M. Ferris, Brown University
R.F. Henn, Brown University
N.J. Wimmer, Brown University
R.F. Valentini, Brown University / Rhode Island Hospital
Correspondent: Click to Email
In this work we evaluate the response of osteoblasts to changing concentrations of the integrin-binding RGD peptide immobilized on gold-coated surfaces. Surfaces were prepared by evaporating 100 Å of titanium onto glass cover slips followed by 800 Å of gold. The peptide Arg-Gly-Asp-Cys (RGDC) and the diluent Cys were bound to the gold through the Cys thiol. 1:0, 1:1, 1:10, 1:100, 1:1000, 1:10000, and 0:1 RGDC:Cys solutions were tested. XPS and SIMS verified peptide immobilization. Osteoblasts isolated from 6-day old rat calvaria were plated at a density of 10,000 cells/cm@super 2@ for one hour and then fixed. Co-localization of actin and vinculin indicates the presence of integrin-based focal adhesions. Vinculin was stained with mouse anti-human vinculin IgG and a rhodamine conjugated secondary antibody. Actin staining was done with FITC / phalloidin. Peptide stability was first assessed by aging uncoated, RGDC coated, and fibronectin coated substrates for 3, 9, 14, and 28 days in serum-free media. Co-localizations were observed on 85-90% of cells on RGDC substrates that had been aged for 3 to 28 days. In contrast, co-localization on fibronectin coated surfaces showed a steady decline with aged specimens and was at the level of plain gold by day 28 (about 30%).The percent of cells showing co-localizations, the number of co-localizations per cell, and cell area all decreased as peptide concentration decreased and were statistically different from 100% RGDC at and below the 1:100 dilution. This study shows that RGDC binds to gold surfaces and influences osteoblast response in a dose-dependent fashion.