Hemoperfusion membranes based on molecularly imprinted membranes of dual-crosslinked polyethyleneimines for efficient plasma bilirubin removal viafrequency-tuned alternating current electric fields

Branched polyethyleneimines (bPEI) were dual-crosslinked with 1,4-butanediol diglycidyl ether and tetrakis(hydroxymethyl)phosphonium chloride to form the molecularly imprinted (MIP) layer for bilirubin. Core/shell-structured membranes (PEO/MIP) with bilirubin-philic cavities were obtained using coaxial electrospinning. Electric polarization (EP) induced the separation of positive and negative charges in the membranes, thereby improving adsorption efficiency. The PEO/MIP was placed between two steel meshes to generate an alternating current electric field (ACEF) during bilirubin adsorption. The maximum adsorption capacity of bilirubin on PEO/MIP increased significantly from 136.99 to 208.33 mg/g when the membranes were subjected to an ACEF at 150 kHz and 2.5 V. The adsorption rate constant of bilirubin on PEO/MIP was also enhanced under EP. Due to the dynamic electrostatic force, the imprinting factor of PEO/MIP in the presence of ACEF was 25 % higher than that in its absence. At 1200 kHz, however, the maximum adsorption capacity of bilirubin on PEO/MIP decreased to 39.4 mg/g because of energy dissipation, which facilitated desorption from the recognition sites. The PEO/MIP could be reused 12 times under polarization switching frequencies ranging from 150 to 1200 kHz, exhibiting low damage and high stability. These results demonstrate that ACEF frequency can manipulate the adsorption behavior of bilirubin, enabling both enhanced bilirubin adsorption and efficient reuse of PEO/MIP.