Biocompatible nanoporous 3D-printed membranes for blood-contacting filtration and apheresis-type separations

Membrane-based blood apheresis systems require high permeance, partial total-protein transmission, excellent haemocompatibility and stable operation under low transmembrane pressures. Conventional phase-inversion membranes are limited by broad pore size distributions, heterogeneous surface chemistry, and progressive fouling, which constrain selectivity and increase pressure requirements. Here, we report nanoporous membranes fabricated by digital light processing (DLP) 3D printing for blood apheresis-type application. The membranes exhibit formulation-dependent nanopore distributions and tuneable surface properties and were integrated into custom flat-sheet membrane modules, with the optimized H-60 formulation displaying a quantitatively near-isoporous through-pore distribution. Five hydrophilic, hydrophobic and copolymer formulations were prepared and evaluated for haemocompatibility using bovine blood. All membranes were non-haemolytic, with haemolysis below 0.5%, and showed moderate thrombogenicity significantly lower than glass controls. The hydrophilic membrane containing 60 wt% pore former displayed water permeances of 83.6 to 92.8 L·h −1 ·m −2 ·bar −1 , with comparable values in phosphate-buffered saline, stable transmembrane pressure and moderate pressure drop under crossflow. During the 270 min of whole-blood filtration, at an initial transmembrane pressure of 0.23 bar, the ultrafiltrate flux decreased by approximately one order of magnitude due to protein deposition prior to stabilising. Total protein rejection ranged from 21 to 56%, indicating partial plasma protein sieving, while permeate haemoglobin remained below 0.1 mg·mL −1 and overall haemolysis stayed within the non-haemolytic range. These results show that resin formulation and pore-former content can be tailored to produce biocompatible 3D-printed nanoporous membranes, including an optimized formulation with a quantitatively near-isoporous through-pore distribution, high hydraulic permeance and compatibility with blood-filtration applications.