Branched Amphiphilic Polylactides as a Polymer Matrix Component for Biodegradable Implants

• Published in: Polymers 2023-03, Vol.15 (5), p.1315
• Main Authors: Istratov, Vladislav, Gomzyak, Vitaliy, Vasnev, Valerii, Baranov, Oleg V, Mezhuev, Yaroslav, Gritskova, Inessa
• Format: Article
• Language: English
• Subjects: Analysis; Biocompatibility; Biodegradability; Biodegradation; Biomedical materials; Chromatography; Composite materials; Composition; Contact angle; Copolymers; Elongation; Glass transition temperature; Hydrophobicity; Hydroxyapatite; Implants; Implants, Artificial; Lactic acid; Liquid chromatography; Materials; Mechanical properties; Melting points; NMR spectroscopy; Polyester resins; Polyethylene glycol; Polylactic acid; Polymerization; Polymers; Propionic acid; Prosthesis; Ring opening polymerization; Solvents; Thermal stability; Water absorption
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym15051315

The combination of biocompatibility, biodegradability, and high mechanical strength has provided a steady growth in interest in the synthesis and application of lactic acid-based polyesters for the creation of implants. On the other hand, the hydrophobicity of polylactide limits the possibilities of its use in biomedical fields. The ring-opening polymerization of L-lactide, catalyzed by tin (II) 2-ethylhexanoate in the presence of 2,2-bis(hydroxymethyl)propionic acid, and an ester of polyethylene glycol monomethyl ester and 2,2-bis(hydroxymethyl)propionic acid accompanied by the introduction of a pool of hydrophilic groups, that reduce the contact angle, were considered. The structures of the synthesized amphiphilic branched pegylated copolylactides were characterized by H NMR spectroscopy and gel permeation chromatography. The resulting amphiphilic copolylactides, with a narrow MWD (1.14-1.22) and molecular weight of 5000-13,000, were used to prepare interpolymer mixtures with PLLA. Already, with the introduction of 10 wt% branched pegylated copolylactides, PLLA-based films had reduced brittleness, hydrophilicity, with a water contact angle of 71.9-88.5°, and increased water absorption. An additional decrease in the water contact angle, of 66.1°, was achieved by filling the mixed polylactide films with 20 wt% hydroxyapatite, which also led to a moderate decrease in strength and ultimate tensile elongation. At the same time, the PLLA modification did not have a significant effect on the melting point and the glass transition temperature; however, the filling with hydroxyapatite increased the thermal stability.