Nature of protein adsorption in artificial tear solution on plasma-irradiated polymethylmethacrylate surface

To evaluate the effect of plasma treatment on protein adsorption onto a polymer surface, we carried out Ar plasma irradiation on polymethylmethacrylate (PMMA) plate and examined the adsorption behavior of protein after immersion of plasma treated PMMA plate in the artificial tear solution containing lysozyme, albumin and gamma-globulin. It was found that the total adsorption of protein in the artificial tear solution to PMMA is suppressed by the Ar plasma treatment. But the adsorption of each component protein differs according to the surface condition of polymers and obviously corresponds to the change with time in the surface wettability. It is concluded that introduction of a hydrophilic group into the PMMA surface by plasma treatment and coming off of it are associated with the adsorption behavior of proteins. Since the adsorption of protein to the plasma-treated PMMA surface changes over time, care should be exercised in determining it, when an attempt is made to clarify the effect of plasma irradiation on the adsorption to the plasma-irradiated polymer surface.