Prussian blue-based theranostics for ameliorating acute kidney injury

Background Acute kidney injury (AKI) with high mortality rates is associated with an excess of reactive oxygen/nitrogen species (RONS) within kidney tissues. Recently, nanomedicine antioxidant therapy has been used to alleviate AKI. Herein, we synthesized ultrasmall Prussian blue nanozymes (PB NZs, 4.5 nm) as theranostic agents for magnetic resonance (MR)/photoacoustic (PA) dual-modal imaging guided AKI treatment. Results PB NZs exhibited multi-enzyme mimetic abilities, promoting the effective elimination of RONS both in vitro and in vivo. Moreover, benefiting from their imaging contrast properties, the rapid renal accumulation of PB NZs was verified by in vivo PA/MR dual-modal imaging. Due to their excellent enrichment in the kidney and unique multi-enzyme mimetic abilities, ultrasmall PB NZs displayed superior AKI treatment efficacy compared with that of amifostine in two clinically relevant types of AKI induced murine models (either by rhabdomyolysis or cisplatin). Conclusion Our findings suggested ultrasmall PB NZs, as nanozyme theranostics, have great potential for AKI management. Graphic abstract

Eco-Friendly Synthesis of SnO2-Cu Nanocomposites and Evaluation of Their Peroxidase Mimetic Activity

The enzyme mimetic activity of nanomaterials has been applied in colorimetric assays and point-of-care diagnostics. Several nanomaterials have been exploited for their peroxidase mimetic activity toward 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide. However, an efficient nanomaterial for the rapid and strong oxidation of TMB remains a strategic challenge. Therefore, in this study, we developed copper-loaded tin oxide (SnO2-Cu) nanocomposites that rapidly oxidize TMB. These nanocomposites have strong absorption at 650 nm and can be used for highly sensitive colorimetric detection. An environmentally friendly (green), rapid, easy, and cost-effective method was developed for the synthesis of these nanocomposites, which were characterized using ultraviolet-visible, energy-dispersive X-ray, and Fourier-transform infrared spectroscopy, as well as scanning electron microscopy. This is the first green synthesis of SnO2-Cu nanocomposites. Their enzyme mimetic activity, which was first studied here, was found to be strongly dependent on the temperature and pH value of the solution. The synthesized nanocomposites have the advantages of low cost, high stability, and ease of preparation for enzyme mimetic applications. Hence, SnO2-Cu nanocomposites are a promising alternative to peroxidase enzymes in colorimetric point-of-care diagnostics.