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).