MRI-responsive nanoprobes for visualizing hydrogen peroxide in diabetic liver injury

Diabetic liver injury has emerged as a significant complication associated with diabetes, warranting increased attention. The generation of hydrogen peroxide (H₂O₂) due to oxidative stress plays a critical role in the onset and progression of this condition. Despite this, there is a scarcity of probes capable of non-invasively, accurately, and reliably visualizing H₂O₂ levels in deep-seated liver in diabetes-induced liver injury. In this study, we introduce a novel H₂O₂-responsive magnetic probe (H₂O₂-RMP), designed for the sensitive imaging of H₂O₂ in the liver injury caused by diabetes. H₂O₂-RMP is synthesized through the co-precipitation of a H₂O₂-responsive amphiphilic polymer, manganese(III) porphyrin (Mn-porphyrin), and iron oxide nanoparticles. When exposed to H₂O₂, the released iron oxide nanoparticles aggregate, resulting in an increased T₂-weighted MR signal intensity. H₂O₂-RMP not only demonstrates a wide dynamic response range (initial r₂ = 9.87 mM^-1s^-1, Δr₂ = 7.69 mM^-1s^-1), but also exhibits superior selectivity for H₂O₂ compared to other reactive oxygen species. Importantly, H₂O₂-RMP exhibits high sensitivity, with a detection limit for hydrogen peroxide as low as 0.56 μM. Moreover, H₂O₂-RMP has been effectively applied for real-time imaging of H₂O₂ levels in the livers of diabetic model mice with varying degrees of severity, highlighting its potential for visual diagnosis and monitoring the progression of diabetic liver injury.