Anti-biofouling phosphorylated HEMA and PEGMA block copolymers show high affinity to hydroxyapatite

Four types of phosphorylated 2-hydroxyethyl methacrylate and poly(ethylene glycol) methyl ether methacrylate (PEGMA) block copolymers were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization and post-phosphorylation. These polymers were composed of different phosphate segments and similar PEG brushes. Polymers with defined phosphate segments were investigated to determine the optimal bonding affinity to hydroxyapatite (HAp). Polymers containing short phosphate segments (as low as 23 mer) were capable of immobilizing on HAp surfaces in situ in a short coating time with considerable durability. After surface modification, the dense PEG brushes altered the interfacial properties of HAp. The protein adsorption on the polymer-grafted HAp was drastically reduced compared with the bare HAp. Furthermore, the presence of the PEG brushes on the HAp surface resulted in bacterial inhibition. The polymer with the shortest phosphate segment (23 mer) showed superior inhibition ability.