Linear and hyperbranched phosphorylcholine based homopolymers for blood biocompatibility

2-Methacryloyloxyethyl-phosphorylcholine (MPC) polymers are zwitterionic in character and are widely used in a range of biomedical devices. The availability of facile polymerization approaches has allowed the synthesis of well-defined MPC polymers, which are now used as delivery carriers for in vitro and in vivo applications. Although biocompatibility testing has extensively been performed on insoluble MPC-based materials, to the best of our knowledge, there are no reports on the hemocompatibility of soluble MPC polymers. Therefore, in this work, linear and hyperbranched MPC polymers of varying molecular weights are synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization. The polymers produced are studied for their blood compatibility, as a function of their molecular weights and structures (linear versus hyperbranched). The hemocompatibility studies including clot formation, complement and platelet activation, and hemolysis indicate that linear and hyperbranched MPC polymers are blood compatible. The remarkable difference in erythrocyte aggregation in the presence of linear and branched MPC polymers indicates the importance of the branched polymer architecture.