Synthesis and Its Urea Adsorption Capacity of Strong Acidic Hollow Nanoparticle

Abstract To enhance the quality of life for dialysis patients while maintaining economic efficiency, the concept of a wearable artificial kidney was proposed and designed approximately two decades ago. However, the primary challenge in the development of a wearable artificial kidney is the adequate removal of urea from dialysate due to its chemical inertness under physiological conditions. Herein, a hollow polystyrene nanoparticle with sulfuric acid groups, named H-CPS-SO 3 H, was synthesized, which could efficiently adsorb urea. H-CPS-SO 3 H was produced in three steps. First, a core-shell polystyrene nanoparticle with a linear core and cross-linked shell was prepared using modified emulsion polymerization. Second, the core-shell nanoparticle was treated with DMF to create a hollow nanoparticle. Finally, the hollow nanoparticle was subjected to sulfuric acid treatment to produce H-CPS-SO 3 H, which was confirmed by both TEM and FTIR analysis. The urea adsorption capacity and kinetics of the as-synthesized H-CPS-SO 3 H were evaluated under a 30 mM urea concentration. Results indicated that H-CPS-SO 3 H had a urea absorption capacity of up to 1 mmol/g, which was achieved after only two hours of adsorption at 37 ℃. These findings demonstrated the high adsorption capacity and favorable adsorption kinetics of H-CPS-SO 3 H. Additionally, it was observed that the adsorption capacity first increased and then slightly decreased with the decrease of pH or the increase of solution volume, while the adsorption capacity sharply decreased with the increase of ionic strength. The results suggest that the prepared H-CPS-SO 3 H has promising application prospects in the field of wearable artificial kidney devices.