Binding Capacity and Adsorption Stability of Uremic Metabolites to Albumin-Modified Magnetic Nanoparticles

Kidney disease causes the retention of uremic metabolites in blood, which is associated with many comorbidities. Hemodialysis does not properly clear many metabolites, including large, middle-sized, and small protein-bound uremic toxins (PBUTs). Adsorption strategies for metabolite removal require the development of engineered adsorbents with tailored surfaces to increase the binding of desired metabolites. Albumin is uniquely positioned for modifying blood-contacting surfaces to absorb uremic metabolites, as it (i) minimizes non-specific protein adsorption and (ii) binds a range of molecules at Sudlow Sites I and II with different affinities. It is unknown if albumin-modified surfaces retain the adsorption qualities of solution-free albumin, namely, adsorption stability or specificity. Herein, albumin was covalently attached to iron oxide nanoparticles and characterized using multiple methods. Metabolite adsorption was conducted by incubating particles in a model solution of thirty-three uremic metabolites associated with kidney failure. Adsorption efficiency, selectivity, and stability were affected by albumin concentration and incubation time. Metabolite adsorption was found to change with time, and it was more effective on albumin-modified particles than unmodified controls. The findings outlined in this paper are crucial for the design of next-generation advanced blood-contacting materials to enhance dialysis and blood purification for patients with kidney disease.