Coacervate Microreactors for Cholesterol-Coupled Nitric Oxide Biocatalysis in Atherosclerosis

Atherosclerosis is driven by metabolic dysregulation, particularly aberrant cholesterol accumulation and impaired nitric oxide (NO) signaling. However, most therapeutic strategies address these abnormalities separately, while biomaterials capable of translating pathological metabolic dysregulation into localized biochemical regulation remain limited. Herein, we report MMCoac@ChOx/HRP, a macrophage membrane-camouflaged coacervate microreactor formed via liquid-liquid phase separation (LLPS). The microreactor features a macromolecularly crowded core self-assembled from poly(diallyldimethylammonium chloride) and sulfobutylether-β-cyclodextrin, which enables cholesterol recognition and enrichment of cholesterol oxidase (ChOx) and horseradish peroxidase (HRP). These co-encapsulated enzymes achieve high enrichment efficiencies of 87.5 and 92.1%, respectively, to drive cholesterol oxidation and subsequent NO generation. In simulated body fluid, MMCoac@ChOx/HRP depleted cholesterol levels from 5.0 to 2.9 ± 0.4 mM and generated 12.1 ± 0.8 μM NO within 12 h. In vitro, it significantly attenuated macrophage foam cell formation and promoted endothelial repair. Furthermore, following systemic administration in ApoE-/- mice, MMCoac@ChOx/HRP preferentially accumulated in atherosclerotic aortic plaques, enhanced in situ NO generation, and reduced aortic plaque burden from 27.4 ± 4.5 to 8.2 ± 3.0%. Overall, this study demonstrates a localized metabolic intervention strategy driven by an LLPS-based microreactor. This versatile biomaterial platform effectively modulates the plaque microenvironment, holding great potential for therapeutic interventions against metabolic syndrome.