Synthesis of biomembrane-mimic polymers with various phospholipid head groups

Lipid bilayers in biomembranes consist of diverse phospholipids, including phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS) with various compositions according to the cell and tissue types. We synthesized biomembrane-mimic polymers, poly(2- methacryloyloxyethyl phosphoric acid) (PMPA), poly(2-methacryloyloxyethyl phosphorylethanolamine) (PMPE), and poly(2-methacryloyloxyethyl phosphorylserine) (PMPS), with PA, PE, and PS head groups, respectively. PA monomer was synthesized from 2-hydroxyethyl methacrylate (HEMA) and dimethyl chlorophosphate (DCP). PE and PS monomers were synthesized from N-tert-butoxycarbonyl (tBoc) protected ethanolamine and serine through the reaction with 2-chloro-2-oxo-1,3,2-dioxaphospholane (COP). Each biomembrane-mimic polymer was successfully synthesized by atom transfer radical polymerization (ATRP) from the monomer. The molecular weight distributions of PMPA, PMPE, and PMPS were analyzed by gel permeation chromatography (GPC) and in vitro cytotoxicity was also examined by 3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assay. The new biomembrane-mimic polymers could be used to prepare a polymeric platform that mimic a cell- or tissue-specific membrane for future applications in biomedical fields such as tissue engineering or bioimplants.