Biodegradable Block Poly(ester amine)s with Pendant Hydroxyl Groups for Biomedical Applications

Abstract

The article presents the results of the synthesis and characteristics of the amphiphilic block terpolymers, built of a hydrophilic polyesteramine block, and hydrophobic blocks made of lactidyl and glycolidyl units. These terpolymers were obtained during the copolymerization of L-lactide with glycolide carried out in the presence of previously produced macroinitiators with protected amine and hydroxyl groups. The terpolymers were prepared to produce a biodegradable and biocompatible material containing active hydroxyl and/or amino groups, with strong antibacterial properties and high surface wettability by water. The control of the reaction course, the process of deprotection of functional groups, and the properties of the obtained terpolymers were made based on 1H NMR, FTIR, GPC, and DSC tests. Terpolymers differed in the content of amino and hydroxyl groups. The values of average molecular mass oscillated from about 5000 g/mol to less than 15,000 g/mol. Depending on the length of the hydrophilic block and its composition, the value of the contact angle ranged from 50° to 20°. The terpolymers containing amino groups, capable of forming strong intra- and intermolecular bonds, show a high degree of crystallinity. The endotherm responsible for the melting of L-lactidyl semicrystalline regions appeared in the range from about 90 °C to close to 170 °C, with a heat of fusion from about 15 J/mol to over 60 J/mol.

Bactericidal Biodegradable Linear Polyamidoamines Obtained with the Use of Endogenous Polyamines

“…The polyamidoamines obtained from spermine exhibited particular activity, which can be explained by the larger number of amino groups in the chain of this polymer. Unlike the polyesteramines described in our previous report [35], the polymers obtained from spermine and putrescine also presented fungicidal activity, though this was much weaker than their antibacterial activity. The quite unexpected strong bactericidal action of the polyamide obtained with putrescine, i.e., without amino groups, against Staphylococcus aureus is difficult to explain at this research stage, and therefore a much more comprehensive study is required.…”