Synthesis and characterization of functionalized water soluble cationic poly(ester amide)s

A new family of positively charged, water soluble and functional amino acid-based poly(ester amide)s (Arg-AG PEA) consisting of four building blocks (L-Arginine, DL-2-Allylglycine, oligoethylene glycol, and aliphatic diacid) were synthesized by the solution copolycondensation. Functional pendant carbon-carbon double bonds located in the DL-2-allylglycine unit were incorporated into these Arg-AG PEAs, and the double bond contents could be adjusted by tuning the feed ratio of L-arginine to DL-2-allylglycine monomers. Chemical structures of this new functional Arg-AG PEA family were confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectra. The thermal property of these polymers was investigated; increasing the methylene chain in both the amino acid and diacid segments resulted in a reduction in the polymer glass-transition temperature. All these cationic Arg-AG PEAs had good solubility in water and polar organic solvents. The cytotoxity of Arg-AG PEAs was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay. These preliminary MTT results indicated that Arg-AG PEAs were nontoxic to bovine aortic endothelial cells (BAECs).