Cell-inspired selective potassium removal towards hyperkalemia therapy by microphase-isolated core-shell microspheres

Hyperkalemia is a common metabolic problem in patients with chronic kidney disease. Although oral medications and hemodialysis are clinically applied for lowering serum potassium , the intrinsic limitations encourage alternative therapy in the trend of adsorbent-based miniaturized blood purification devices. Cells serve as the biological K + storage units that accumulate K + through multiple mechanisms. Inspired by cells, our strategy aims at favorable permeation and enrichment of K + in the microsphere . We incorporate cation-affinitive groups into core-shell structures with submicron-sized phase separation. These nano-spaced side-groups cooperate to form interlinked clusters, where crown ethers with Angstrom-scale ring for size-matched complexation, while ionic sulfonic acid groups for hydrophilicity and charge-buffering. The unique structure with such non-covalent interactions facilitates K + for permeation across the shell and binding to the core while also ensuring mechanical strength and anti-swelling durability in biofluids. The microspheres exhibit high selectivity ratios of K + ( S K/Na , S K/Ca , S K/Mg up to 9.8, 21.6, and 17.7). As column adsorbents for hemoperfusion simulation, they effectively lower elevated K + levels to the normal range (clearance rates up to 44.4%/45.3% for hyperkalemic human serum/blood). Blood compatibility tests show low protein adsorption , preferable hemocyte compatibility, and anticoagulation property in vitro. This promising strategy has clinical potential for hyperkalemia in high-risk patients. Statement of significance Hyperkalemia (serum potassium >5 mmol/L) is a common complication in chronic renal failure patients. The limitations of existing treatments prompt a shift to wearable artificial kidney technology for clinical convenience and efficacy. Existing treatments have limitations, and we turn to adsorbent-based miniaturized blood purification devices in the prospect of wearable artificial kidney technology. There exists a lack of ion-specific adsorbents applied in extracorporeal circuits to redress electrolyte imbalances like hyperkalemia. Inspired by cells, we aim at the favorable permeation and enrichment of K + by microspheres. The microspheres have a microphase-isolated core-shell structure, whose nano-spaced groups form cation-affinitive clusters. Selective K + removal and blood compatibility are achieved. We expect this strategy to enlighten alternative hyperkalemia therapy for these high-risk patients.