Effect of the Surface Structure of Poly(styrene-co-acrolein) Microspheres and Its Modification by Protein on Electrosurface Properties

The electrophoretic mobility of poly(styrene-co-acrolein) microspheres was studied as a function of storage time. It was shown that pH_IEP2.0 is retained but the abnormal dependence of electrophoretic mobility on NaCl concentration is replaced by classical dependence. When comparing chemisorption of bovine serum albumin (BSA) on the microsphere surface for various latex samples, the differences in the isotherm patterns was revealed; moreover, the prevalence of surface concentration of carboxyl groups over that of aldehyde groups resulted in a decrease in adsorption. After the modification of the microspheres by protein, the values of pH_IEPfall within the range of 3.5–5.0 and their dependence on the amount of surface-bound protein passes the minimum. The results obtained are discussed in terms of the different arrangement patterns of protein molecules on the microsphere surface and the changes of BSA macromolecule conformations under the effect of a dispersion medium and as a result of chemical interaction with the polymer surface.