Isopropyl alcohol plasma modification of polystyrene surfaces to influence cell attachment behaviour

An isopropyl alcohol plasma has been used to modify polystyrene surfaces by the deposition of a hydrophilic thin film. The films have been characterised by X-ray photoelectron spectroscopy, atomic force microscopy and water contact angle measurements. These studies show the oxygen content of the modified surfaces increases with treatment time up to ∼10 at.% after 600 s. Monochromated XPS results show the surface oxygen to be in the form of carbonyl and alcohol/ether groups with a complete absence of carboxyl species. The suitability of the modified surfaces for cell culture was assessed by the growth of transformed human fibroblast cells (1BR.3N) in the presence of serum proteins which made up ∼10% (v/v) of the culture media. Plasma treatment times >60 s were found to result in cell attachment and proliferation rates comparable to tissue culture polystyrene which has a similar total surface oxygen concentration with the addition of a carboxyl group functionality. A simple chemical patterning technique was used to produce chemically heterogeneous surfaces for spatially resolved cell attachment studies. 1BR.3N cells were found to attach preferentially to the areas exposed to the plasma which were more hydrophilic than the untreated regions.