XPS and SERS Studies of Cell Adhesion-controlled Polymer Modified by Ion Implantation

Abstract

X-ray photoelectron spectroscopy (XPS) of Ne ion-bombarded polymer has been carried out in order to examine the cause of HeLa cell adhesion control on polymers. Substrates used were polystyrene (PS) and oxygen plasma-treated polystyrene (PS-O). Neon bombardments into the patterned region of PS and PS-O were performed at an energy of 150 keV with fluences of 1×1014 and 1×1015 ions cm-2. The surface chemical bonding states were investigated by XPS. In HeLa cell adhesion measurements, the Ne-bombarded region of PS with a fluence of 1×1015 ions cm-2 exhibits higher adhesion and spreading of HeLa cells than the unbombarded region. On the contrary, it is found that the Ne-bombarded region of PS-O inhibits HeLa cell adhesion. The XPS results show that Ne bombardment to PS or PS-O destroys the original chemical bonds and consequently produces new functional groups. It is considered that the drastic change of surface chemical bonding states from the pristine states induced by Ne bombardment leads to a clear distinction between increasing and inhibiting HeLa cell adhesion.