Synthesis and characterization of amino-functional polyesters composed of lactic acids and serine amino acids.

Functional polyesters with good biocompatibility are always important biomaterials. In this study, poly (latide- co - N -trityl serine ester)s (P (LA- co -TSL)s) were synthesized through the copolymerization of lactide (LA) and N -trityl serine lactone (TSL) in toluene under 90 °C with the catalysis of diethylzinc. The molecular weight (Mn) of P (LA- co -TSL) with different TSL molar ratios (4.5%, 8.8%, 25.2%, 41.7% and 100 mol%) ranged from 3.7 kDa to 7.2 kDa with the polydipersity index (PDI) from 1.40 to 1.57. The chemical structure of poly (LA- co -TSL)s was characterized by FTIR, 1H NMR and 13C NMR spectroscopy. As the proportion of TSL in P (LA- co -TSL) increased, the glass transition temperature (Tg) of P (LA- co -TSL) increased gradually, from 56 °C of PLA to 161 °C of Poly (TSL). The initial weitht loss temperature of P (LA- co -TSL) increased as the ratio of TSL increased, from 172 °C of PLA to 230 °C of Poly (TSL). Upon removal of the N -trityl protecting group, amino functional poly (latide- co -serine ester) (P (LA-co-SL)) was realized and confirmd by FTIR and 1H NMR spectra. GPC displayed approximately 19.5% polyester backbone degradation during deprotection with trifluoroacetic acid. DSC analysis illustrated better crystallization properties of the copolyester after amino group deprotection. Using mPEG as an initiator, a new type of block copolymer, mPEG- b -poly (latide- co - N -trityl serine ester)s (mPEG- b -P (LA- co -TSL)s), was obtained. After N -trityl removal, mPEG- b -P (LA- co -TSL) displayed excellent cytocompatibility in L929 cell culture experiments. [Display omitted] • Polyesters with lateral amino-functional groups derived from serine were synthesized and characterized. • Lactide and N -trityl-serine lactone monomers are distributed disorderly along the polyester backbone. • Cell culture experiments demonstrated the excellent cytocompatibility of mPEG- b -poly (lactide- co -serine ester)s. [ABSTRACT FROM AUTHOR]