Photoregenerable nanoadsorbents with macromolecular brushes for the clearance of bilirubin in serum

The ultrahigh concentration of bilirubin (BR) is recognized as a key factor leading to biliary cirrhosis and irreversible brain damage, with the efficient removal of BR from blood being an effective therapy against these conditions. However, the practical application of adsorbents for blood purification is often compromised by their poor regenerative performance. Therefore, by leveraging the excellent structure-function properties of stimuli-responsive materials, we developed photoregenerable nanoadsorbents (SiO2@MAzoPy–x) with excellent cyclic removal performance. We employed azobenzene macromolecule brushes as the functional ligand to enhance the adsorption performance of the nanoadsorbents and enable efficient regeneration. The best-performing nanoadsorbent exhibited BR adsorption rates of 69.71% and 65.20% in phosphate-buffered saline (PBS) and simulated plasma, respectively, and showed superior adsorption efficiency in patients' serum compared to the unmodified SiO2 (≤5.4%). The binding mechanism suggested that BR and the nanoadsorbent interacted through hydrophobic and electrostatic forces. Importantly, the nanoadsorbents could be photoregenerated with a recovery rate of 99% in PBS after five regeneration experiments using a green process. Owing to their superior photoregenerative properties, the proposed nanoadsorbents show promise for clinical application.