Carboxymethyl chitosan modification via EDC/NHS-mediated amidation for performance improvement on blood-contacting biomedical membranes

Blood-contacting membranes require hydrophobicity to prevent leakage but suffer from poor hemocompatibility. Hydrophilic modification represents a key strategy to address this limitation. Herein, hydrophilic carboxymethyl-chitosan (CMCS) modification onto polyethersulfone (PES) membrane (CMCS-PES) was achieved via thermal-crosslinking and amidation reaction, followed by characterization through SEM, AFM, FTIR, XPS, BET, as well as water contact angle measurements, and systematic evaluation for its performance in hemocompatibility, antibacterial activity, long-term stability, and gas permeation. Compared with unmodified PES membranes, CMCS-PES membrane showed excellent hydrophilicity with surface water contact angle reduced from 84.3° to 30.9°, displayed improved hemocompatibility with bovine serum albumin adsorption decreased from 57.76 to 31.32 μg/cm 2 , bovine γ-globulin from 47.26 to 27.45 μg/cm 2 , hemolysis rate reduced from 0.9 % to 0.3 %, prolonged activated partial thromboplastin time by 12.4 s, lower blood fibrinogen level by 20 %, and exhibited good antibacterial activity with inhibition on E. coli growth by 28.9 % and S. aureus by 42.76%. Moreover, the CMCS-PES membrane still presents competitive gas permeation in comparison to other membranes investigated under similar conditions, and demonstrated excellent long-term stability in preventing blood leakage and platelet adhesion. This research provides an effective modification strategy for hemocompatibility improvement on blood-contacting membranes.