Metal–organic framework (UiO-66 and UiO-66-NH2)-based adsorbents for bilirubin removal used in hemoperfusion

Excessive accumulation of bilirubin in patients with hyperbilirubinemia can lead to tissue and organ damage and neurological diseases, and is even life-threatening in severe cases. Hemoperfusion is an effective method for removing bilirubin, but clinically used hemoperfusion adsorbents have unsatisfactory adsorption capacity and kinetics. In order to obtain a safe and efficient bilirubin adsorbent, Zr-based Metal-Organic Framework (MOF) material UiO-66 with high specific surface area and aqueous medium stability was prepared and modified with varying degrees of amination to improve its adsorption capacity. According to adsorption experiments in aqueous solution and simulated plasma, it was confirmed that the unsaturated coordinated zirconium in UiO-66 can effectively induce the aggregation and precipitation of free bilirubin unbound to albumin and the amino group on UiO-66-NH₂ has a strong affinity for albumin bound bilirubin. The adsorption effect of UiO-66-NH₂ with a high degree of amino modification is significantly stronger than that of UiO-66-NH₂ with a low degree of modification. In simulated plasma with a bilirubin concentration of 40 mg dL^-1, the adsorption capacities of UiO-66 and UiO-66-NH₂-1.9 can reach 69.08 mg g^-1 and 81.13 mg g^-1. The adsorption isotherm fitting and adsorption kinetics fitting results also show that UiO-66 and UiO-66-NH₂ are good adsorbents for bilirubin. In dynamic adsorption, the adsorbents also showed good performance and did not affect the protein in the plasma. The hemolysis test, coagulation time test, and cytotoxicity test confirmed that the bilirubin adsorbents based on UiO-66 and UiO-66-NH₂ have good blood compatibility and biocompatibility. This study provides new ideas for the development of a novel bilirubin adsorbent and a theoretical basis for the study of bilirubin adsorption mechanisms.