Synthesis, characterization and biodegradation of functionalized amino acid-based poly(ester amide)s

A series of biodegradable functional amino acid-based poly(ester amide)s (PEA-AG) were designed and synthesized by the solution co-polycondensation of amino acid (L-phenylalanine and DL-2-allylglycine) based monomers and dicarboxylic acid based monomers. Pendant carbon-carbon double bonds located in the DL-2-allylglycine were incorporated into these PEA-AGs, and the double bond contents could be adjusted by tuning the feed ratio of L-phenylalanine to DL-2-allylglycine monomers. Chemical structures of this new functional PEA-AG family were confirmed by FTIR and NMR spectra. The thermal properties of these polymers were investigated; increasing the methylene chain in both the amino acid and dicarboxlic acid segments resulted in a reduction in the polymer glass-transition temperature. The short-term in vitro biodegradation properties of PEA-AGs were investigated as a function of PEA-AG chemical structures and enzymes. Based on the weight loss data, PEA-AGs biodegraded much faster in an enzyme solution than in a PBS buffer solution. The utility of the pendant functional carbon-carbon double bonds in PEA-AG was demonstrated by synthesizing additional functional PEA derivatives. The incorporation of the functional pendant carbon-carbon double bonds along the PEA-AG chains could significantly expand the biomedical applications of these functional PEA-AGs via either their capability to conjugate bioactive agents or prepare additional useful functional derivatives.