Construction of bionic enzyme gas channels on the surface of PMP hollow fiber membrane for rapid CO2 removal in ECCO2R system

The extracorporeal carbon dioxide removal (ECCO 2 R) system is a life-support technique that has been shown to facilitate a protective ventilation strategy. When the lung disease cannot remove carbon dioxide (CO 2 ) in time, resulting in CO 2 retention, ECCO 2 R is used to remove the excess CO 2 . As the key component of the artificial lung, the gas transport performance of the membrane determines the CO 2 removal capacity of the membrane lung, which should present high CO 2 selectivity to increase the efficient CO 2 removal rate. In this study, a biomimetic metalloenzyme, ZIF-8-NH 2 , was prepared to mimic the function of carbonic anhydrase (CA). The pore in ZIF-8-NH 2 was constructed to act as gas channel, in order to enhance the CO 2 /O 2 selectivity. ZIF-8-NH 2 /Pebax, which has functions similar to those of CA and gas channel (AQP1), was coated on the surface of poly(4-methyl-1-pentene) (PMP) membranes to fabricate the composite membrane. The results confirmed that the CO 2 /O 2 selectivity of the ZIF-8-NH 2 /Pebax composite membrane was 7.4, which was 7.5 times higher than that of the pristine PMP membrane (1.0). The protein adsorption and thrombin time were 35.5 % lower and 34.4 % higher than those of PMP hollow fiber membrane (44.9 μg/cm 2 and 27.6 s), respectively. These results demonstrated that the prepared composite membrane possessed good blood compatibility. Additionally, an in-vitro blood circulation device was established to comparatively evaluate the hemocompatibility and CO 2 removal efficiency of PMP and the composite membrane modules under dynamic blood flow. Meanwhile, the corresponding results exhibited that the modified coating has good biosafety, implying that the mentioned materials can be safely applied in clinical trials.