Poly(lactic acid)-poly(ethylene glycol) asymmetric membranes with enhanced hemocompatibility and gas exchange performance for artificial oxygenation.

The biomedical application of poly(lactic acid) (PLA) in extracorporeal membrane oxygenation (ECMO) remains largely unexplored. Herein, a PLA-PEG block copolymer membrane with an optimized composition was specifically engineered for ECMO applications. The membrane exhibited markedly enhanced surface hydrophilicity (water contact angle of 57.5°) while maintaining robust mechanical properties (tensile strength of ~12 MPa and elongation at break of ~37%). Most importantly, it demonstrated substantially improved hemocompatibility, with an ~60% reduction in dynamic plasma protein adsorption compared to unmodified PLA, significant suppression of platelet adhesion, and a hemolysis rate (1.09%) well within the clinically safe range. Under simulated ECMO conditions, the membrane achieved rapid blood oxygenation, raising oxygen saturation from 23% to >85% within 30 min and reaching full saturation (>95%) by 45 min, while simultaneously normalizing carbon dioxide levels. Furthermore, the M-3 membrane displayed excellent long-term stability, withstanding pressures up to 0.4 MPa for >60 min without leakage, far exceeding typical ECMO operating conditions, and maintaining stable surface wettability after 30 days of water immersion. Molecular simulations revealed that the enhanced hemocompatibility originated from the formation of a stable PEG-derived hydration layer that selectively weakened amino acid adsorption while preserving the polymer's electronic structure. The PLA-PEG membrane system showed overall excellent performance in hemocompatibility, gas exchange efficiency, pressure resistance, and long-term stability for ECMO applications, thus representing a promising alternative to current oxygenator membranes.