Acido-Alcoholyzed Products of Polylactide (PLA) and Their Use in Enhancing Mechanical Properties, Hydrophilicity, And Cell Compatibility of PLA Nanofibers for Tissue Engineering Applications

Alcoholysis and acidolysis effectively transesterify polylactide (PLA) resin into small or medium-sized lactate oligomers with tunable hydrophilicity. The products can then be used to prepare various functional materials. This work employed 2, 2-bis(hydroxymethyl) propionic acid (DMPA) to generate small-sized PLA oligomers with carboxylic and hydroxyl terminals. The chemical structures and compositions of the acido-alcoholyzed PLA (aPLA) were analyzed by proton nuclear magnetic resonance (¹H-NMR) and Fourier transform infrared (FTIR) spectroscopy. The optimum product was blended with PLA resin and fabricated into electrospun nanofibers to increase their mechanical properties, hydrophilicity, and biocompatibility. The surface morphology, chemical structures, crystallinity, and properties of the PLA/aPLA blends were characterized by scanning electron microscopy (SEM), FTIR, X-ray diffraction (XRD) spectroscopy, water contact angle (WCA) measurements, tensile tests, and biocompatibility tests. Nanofibers with a ragged surface morphology and a 900-1500 nm size range were generated. The fibers showed higher crystallinity due to the enhanced crystallization induction by the acid and hydroxyl chain ends. Incorporating aPLA increased the elongation at break and the toughness of the fiber mats due to the plasticizing effect and the higher compatibility of aPLA in the PLA matrix. The hydrophilicity of the fiber mats also improved due to the higher contents of the polar end groups, leading to high water absorption in a short time. The cell compatibility results confirmed that the fibers containing 20% aPLAs were suitable for incubating L929 fibroblast cells, which was reflected in the higher adhesion and growth on the cells on the fiber mats within 7 days. The materials have high potential for use in tissue engineering scaffolding and biomedical applications.