Ordered mesoporous SiO2 as hemoperfusion adsorbents for enhanced selectivity of bilirubin removal from blood

Excessive bilirubin poses a significant risk factor in the progression of chronic liver disease. However, due to its nature as an albumin-bound toxin, bilirubin cannot be efficiently eliminated through conventional hemodialysis therapy or existing hemoperfusion adsorbents, presenting a challenge in selective removal. It is widely acknowledged that adjusting the pore properties of adsorbents can impact the adsorption efficiency of a hemoperfusion adsorbent. However, few studies have been working on improving the selectivity of bilirubin removal through precise regulation of pore size. In this paper, we aim to demonstrate that the selectivity of bilirubin removal can be achieved and enhanced by fine-tuning the pore size of ordered mesoporous materials. Ordered mesoporous SiO₂ (OMS) is selected as the research object due to its highly organized and uniform porous structure, as well as its excellent biocompatibility. The results indicate that OMS nanoparticles with a pore diameter of 2.5 nm (OMS-2.5 nm) exhibit superior adsorption capacity for bilirubin in both pure and albumin-rich solutions, suggesting the potential for achieving efficient and selective bilirubin removal through pore size optimization. Furthermore, to demonstrate the feasibility of OMS nanoparticles in practical applications (i.e. their inheritability of selectivity), we engineered OMS nanoparticles into polyvinyl alcohol (PVA) microspheres, forming OMS/PVA composite microspheres. The incorporation of OMS nanoparticles significantly enhances the bilirubin adsorption capacity of PVA microspheres while simultaneously reducing their albumin adsorption. The excellent selective adsorption efficacy of OMS-2.5 nm is preserved in the composite microspheres, underscoring its potential therapeutic benefits for treating diseases with excessive bilirubin levels.