o acid functionalized biodegradable polyesters for pharmaceutical and biomedical applications
Over the past decades, great effort has been made to introduce naturally occurring amino acids (AA) into synthetic polymers. Including or graing an AA along a polymeric backbone may (i) tailor the chirality; (ii) offer new functional groups capable of interacting with drugs, proteins and nucleic acids; (iii) facilitate a further anchoring with other bioactive molecules; (iv) modulate the hydrophilicity/hydrophobicity of the system; or (v) improve the non covalent interactions leading to the formation of hierarchical ordered superstructures. Ring opening polymerization (ROP) of both canonical and non canonical amino acid N carboxyanhydrides (NCA) results in a common strategy to develop synthetic poly peptide/poly(amino acids) In order to usually prepare NCAs, side chain protected AAs are routinely phosgenated. The need to functionalize and protect AAs beforehand renders the pre polymerization steps tedious from the point of view of purication and monomer moisture sensitivity. Classic NCA polymerizations due to side reactions, such as chain transfer and chain termination, suffer crucial limitations in both designing well dened co polymers, and reaching well dened molecular weights. Some alternatives have been developed, such the introduction of organometallic catalyst, vacuum conditions, and the use of low temperature. Despite all these aforementioned pioneering polymerization