Morphology Control and Properties of PLA Hollow Fibers Seeking Peripheral Nerve Regeneration

Poly(lactic acid) (PLA) hollow-fiber membranes were prepared by wet spinning with phase-inversion technique, in order to prepare artificial transplants for peripheral nerve injury, also kown as Neural Guide Coundits (NGC).

Dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), and 1,4-dioxane (DIO) were applied as solvents (Ss), and water was
applied as a nonsolvent in the precipitation bath. The polymer solution viscosities, PLA–S–water miscibility regions, and precipitation
onsets were measured and related to the Hansen solubility and Flory–Huggins interaction parameters. It was observed a morphological
transition from fingerlike to spongelike pores when DIO was applied as the S instead NMP or DMSO. The study of preparing conditions and addition of porogens such as PVP allowed production of hollow fibers with water permeabilities from 0 to 9.38 L/m2 bar, with rejections of 100% of BSA (67 KDa) and 83 to 100% of lysozyme (17 kDa).

In vivo funcional evaluation in mice was able to elucidate questions about the influence of porosity of the hollow fibers during the treatment. Resrults showed that the functional recovery of the synthesized membranes in this work were equal or even superior compared to values reported in the open literature, mostly regarded to sensorial evaluation. Nonporous hollow fibers showed faster sensorial recovery (2 weeks) while full recovery after 5 weeks was observed with porous membranes.