The combination of micron and nanotopography by H(2)SO(4)/H(2)O(2) treatment and its effects on osteoblast-specific gene expression of hMSCs.

H(2)SO(4)/H(2)O(2) treatment of titanium implants imparts nanofeatures to the surface and alters the osteoblast response. The aim of this study was to evaluate the effect of H(2)SO(4)/H(2)O(2) treatment of commercially pure Titanium (cpTi) surfaces on gene expression of human mesenchymal stem cells (hMSCs) differentiated into osteoblasts. Commercially pure grade IV titanium disks (20.0 mm x 1.0 mm) were polished or polished and subsequently treated by grit blasting or grit-blasting/acid etching with an H(2)SO(4)/H(2)O(2) solution. The surfaces were divided into three groups: smooth (S), grit-blasted (Gb), and nanostructured: grit-blasted/acid etched (Nano). Surfaces were examined by scanning electron microscopy and atomic force microscopy. HMSCs were grown on the disks. The data points analyzed were at 3, 7, 14, and 28 days. Real-time PCR was used to measure the mRNA levels of ALP, BSP, Runx2, OCN, OPN, and OSX. The housekeeping gene GAPDH was used as a control. Descriptive statistics were calculated using Microsoft Excel. T-test was performed for comparison of mRNA levels when compared with S surfaces (p < 0.05). All osteoblast-specific genes were regulated in surface-dependent patterns and most of them were upregulated on the Nano surfaces. Runx2 and OSX mRNAs were more than threefold upregulated at days 14 and 28 on Nano. Higher levels for ALP (38-fold), BSP (76-fold), and OCN (3-fold) were also observed on the Nano surfaces. A grit-blasted surface imparted with nanofeatures by H(2)SO(4)/H(2)O(2) treatment affected adherent cell bone-specific gene expression. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.