STUDIES ON SUSPENSION AND EMULSION .130. PREFERENTIAL ADSORPTION OF BOVINE FIBRINOGEN DIMER ONTO POLYMER MICROSPHERES HAVING HETEROGENEOUS SURFACES CONSISTING OF HYDROPHOBIC AND HYDROPHILIC PARTS

The adsorption onto polymer microspheres of bovine fibrinogen (BFb) containing both dimeric and monomeric species was examined using various homopolymer, copolymer, and poly (2-hydroxyethyl methacrylate)/polystyrene composite microspheres which were produced by the emulsifier-free (seeded) emulsion polymerization technique. The preferential adsorption of the BFb dimer was clearly observed in an optimum region of the surface hydrophilicities of the polymer microspheres. The preferential adsorption of the BFb dimer onto the composite polymer microspheres having heterogeneous surfaces with both hydrophilic and hydrophobic parts was more remarkable than that onto the homopolymer and copolymer microspheres having homogeneous surfaces. The behavior is discussed in comparison with those for bovine serum albumin and human gamma-globulin.