Fabrication of Hydrophilic Polymer Brushes on Polystyrene Substrate by Plasma-based Surface Functionalization

摘要

Polystyrene (PS) is one of most common polymers used in biomaterials because of its optical transparency, good mechanical properties and low production cost, etc. However, due to several intrinsic surface properties of PS including hydrophobicity, the biomaterials made of PS are limited in their biomedical applications. For example, the nonspecific adsorption of biological molecules including proteins on the surface is often observed. In order to improve surface property of PS for biomedical use, plasma treatment has often been used to introduce new oxygen-and/or nitrogen-containing groups on the PS surface without affecting the bulk properties. [1-4] However, the surfaces obtained by simple plasma treatment have been shown to be most unstable with respect to both washing and aging. [5-8] As the other methods, covalent immobilization and grafting of hydrophilic polymer such as poly(ethylene glycol) (PEG) and dextran have been examined for reducing nonspecific protein adsorption onto hydrophobic polymer substrate. On the other hand, surfaces covered with bioinert polymer such as PEG may not be enough for some application due to absence of functional groups for further modification. In fact, the development of biosensor requires controlled immobilization of bioactive molecules for specific detection of a target molecule on excellent anti-fouling substrate surface.