Surface modification of silica glass by CHF3 plasma treatment and carbon negative-ion implantation for cell pattern adhesion

We have investigated a method for the patterning of cell adhesion on a silica glass by using two-steps of surface modification processes of CHF3 plasma treatment and negative-ion pattern implantation. For the first step, exposure of CHF3 plasma to silica glass (SG) was used to obtain hydrophobic surface, leading to eliminate cell-adhesion property. After treatment with RF power of 20 W and exposure time of 120 s, the hydrophobicity was occurred from the increase in contact angle of SG from 43 degrees to 88 degrees and its reason based on XPS analysis was due to formations of C-F, C-F-2, and C-F-3 bonds, so-called fluorocarbonated bonds. Culture of mesenchymal stem cells (MSC) and rat adrenal pheochromocytoma cells (PC12h) showed the degradation of cell adhesion property on the plasma-treated SG surface. For the second step, carbon negative-ion implantation into the hydrophobic fluorocarbonated-SG surface was used to pattern the hydrophilic region, leading to enhance cell adhesion property. The contact angle of C-modified surface decreased to 76 degrees at conditions of 15 keV and 1 x 10(15) ions/cm(2). XPS showed that the hydrophilicity was due to reduction of C-F-x bonds and formation of C-O and C=O bonds. After 3 days culture of MSC and PC12h on the C-implanted surface of the plasma-treated SG, a fairly good adhesion patterning of both cells was obtained on the ion-implanted regions. (C) 2011 Elsevier B.V. All rights reserved.