Kinetics of cell adhesion to polymer surfaces

Results of the kinetics of adhesion of granulocytes as well as fresh and glutaraldehyde-fixed erythrocytes, suspended in Hanks Balanced Salt Solution (HBSS; pH 7.2, ionic strength of 0.15) to various polymeric substrates are presented. Cell adhesion increases rapidly initially and reaches a plateau value after approximately 30 minutes. There is no evidence for a lag-time in the onset of cell adhesion, suggesting that electrostatic double-layer forces are negligible under these experimental conditions. For the experiments in which the cells are suspended in HBSS, which has a surface tension larger than that of the cells, the level of cell adhesion increases with decreasing surface tension of the polymeric substrates. An additional experiment with fresh human granulocytes suspended in HBSS containing 10% dimethyl sulfoxide was also performed. The surface tension of the resulting liquid medium is below that of the cells and the pattern of adhesion is reversed, in agreement with the predictions of a thermodynamic model for cell adhesion. The slightly different behavior of siliconized glass as a substrate is discussed in terms of "screening."