EFFECTS OF SURFACE MODIFICATION OF MATERIALS ON HUMAN NEUTROPHIL ACTIVATION

The properties of a polymer surface affect the cellular functions and morphology of cells in contact with the polymer. In this paper, we wil l demonstrate the effects of surface modification of materials on vari ous neutrophil markers of activation. The sulfonation of a polystyrene surface caused increases in its negative charge and hydrophilicity. T he sulfonation did not affect the number of adhered neutrophils, but t he shape of the neutrophils adhered on the material was different; a r ound shape on highly sulfonated polystyrene and a spread shape on weak ly sulfonated or non-sulfonated polystyrene. Expression of the adhesio n molecule, CD11b, on neutrophils was also affected by the properties of the polymer surface. CD11b was expressed in neutrophils adhered on polystyrene and the expression decreased with increasing sulfonation o f the surface. The expression of CD11b on the neutrophils on highly su lfonated polystyrene was the same as that on non-adhered neutrophils. In contrast, the expression of CD11a was not affected by the propertie s of the material surface. The F-actin content of activated neutrophil s and the production of active oxygen groups detected by means of lumi nol-dependent chemiluminescence were also dependent on the sulfo-group content of the material surface. Finally, the translocation of protei n kinase C (PKC) was determined in neutrophils adhered to these materi als. Compared to non-adhered cells, the ratio of membrane bound to cyt osolic PKC increased in adhered cells, but the increase was suppressed by sulfonation of the material surface. These data suggest that activ ation of neutrophils on polystyrene is suppressed by surface modificat ion with increasing negative charge and/or hydrophilicity.