Self-organization of dipeptide-grafted polymeric nanoparticles film: A novel method for surface modification

Novel dipeptide-grafted polymeric nanoparticles were prepared by grafting the dipeptide (Gly-Gly) to a block copolymer backbone, comprised of styrene-alt-(maleic anhydride) and styrene. In aqueous solution PSt₁₃₀-b-P(St-alt-MAn)₅₈-g-GlyGly₂₆ formed stable dispersed spherical aggregates of ca. 75 nm. The critical micelle concentration for the dipeptide-grafted block copolymer self-aggregates was 6.3 × 10⁻³ mg mL⁻¹. The zeta-potential of the aggregates was estimated experimentally. The dispersed polymer nanoparticles effectively self-organized to form stable nanoparticle thin films on hydrophobic solid surfaces, such as octadecyltrichlorosilane modified glass (OTS-G). As the ionic strength and temperature of the polymer suspension increased the surface coverage of the nanoparticle film increased and its hydrophobicity (water contact angle) decreased. Significantly less bovine serum albumin (BSA) adsorbed to nanoparticles modified surfaces with compared OTS-G surfaces. Diglycine grafted polymer nanoparticles have the potential to be used as a novel platform to study protein-protein interactions and to control fouling.