Composite polymer particles prepared with different amounts of acrylic acid and their usefulness as carriers for biomolecules

Modification of surface properties of polymer particles suitable for biomedical application has been done by incorporating acrylic acid (AA) as a hydrophilic component. First, submicron-sized poly(methyl methacrylate) seed particles were prepared by soap-free emulsion polymerization. Then, seeded emulsion copolymerizations were carried out with varying proportions of AA and methyl methacrylate (MMA). MMA was used as a comonomer to prevent the dissolution of AA from the polymer particles. The adsorption behaviors of different biomolecules indicate that the surface of the composite polymer particles is sufficiently hydrophilic, particularly at higher AA content. Specific activities of adsorbed trypsin on the composite polymer particles were also comparatively high compared to free trypsin, which suggests that the adsorbed trypsin undergoes only slight conformational change owing to the interaction with the surface of particles.[PUBLICATION ABSTRACT]