Amphiphilic poly(lactic acid) membranes with low fouling and enhanced hemodiafiltration

Abstract

Hemocompatible membranes were obtained by blending of poly(lactic acid) PLA with 3 different amphiphilic block copolymers, poly(methyl methacrylate)-b-poly(2-acryloamido-2-methyl-1-propanesulfonic acid) (PA), poly(methyl methacrylate)-b-poly(2-hydroxyethyl methacrylate) (PH) and poly(methyl methacrylate)-b-poly(2-dimethylamino ethyl methacrylate) (PD). These membranes presented a promising balance between middle-size molecules convective transport and desirable proteins retention. Copolymers segregation to the membrane surface was confirmed by X-ray photoelectron spectroscopy (XPS). Contact angle decreases from 79.6° for pure PLA membrane to 73.9° to 61.0° for the membrane containing the amphiphilic block copolymers, which leads to an increase in anti-fouling properties and water flow through the membranes. All membranes exhibited hemocompatibility and non-hemolyzing properties. PLA/PH blend membranes presented the highest urea (94.7% and 72.5%) and lysozyme (54.2% and 40.5%) clearance with Bovine Serum Albumin (BSA) retention between 90 and 91 %. PLA/PA exhibited the highest BSA retention (99.3%) with moderated urea (80.2%) and lysozyme (17.4%) clearance. Thus, the proper combination of amphiphilic copolymer with PLA will allow fine-tuning the middle-molecule toxin separation with high retention of large desirable proteins through the membranes.