Upconversion nanoparticles-CuMnO2 nanoassemblies for NIR-excited imaging of reactive oxygen species in vivo

A novel ratiometric luminescent nanoprobe based on UCNPs-CuMnO2 nanoassemblies has been successfully applied to the detection of ROS in vitro and in vivo. [Display omitted] •A ratiometric luminescent nanoprobe based on UCNPs-CuMnO2 nanoassemblies has been constructed for ROS sensing.•CuMnO2 acts as an effective quencher to the upconversion luminescence and recognition unit for ROS.•The redox reaction between CuMnO2 and ROS under acidic conditions, that would induce the recovery of luminescence signal.•The synthesized nanoprobe has been proved to monitor ROS level in living cells and tumor sites.•The luminescent sensor is capable of excellent performance in sensitivity, selectivity, stability, and response time. Here, we designed a ratiometric luminescent nanoprobe based on lanthanide-doped upconversion nanoparticles-CuMnO2 nanoassemblies for rapid and sensitive detection of reactive oxygen species (ROS) levels in living cells and mouse. CuMnO2 nanosheets exhibit a wide absorption range of 300–700 nm, overlapping with the visible-light emission of upconversion nanoparticles (UCNPs), resulting in a significant upconversion luminescence quenching. In an acidic environment, H2O2 can promote the redox reaction of CuMnO2, leading to its dissociation from the surface of UCNPs and the restoration of upconversion luminescence. The variation in luminescence intensity ratio (UCL475/UCL450) were monitored to detect ROS levels. The H2O2 nanoprobe exhibited a linear response in the range of 0.314–10 μM with a detection limit of 11.3 nM. The biological tests proved the excellent biocompatibility and low toxicity of obtained UCNPs-CuMnO2 nanoassemblies. This ratiometric luminescent nanoprobe was successfully applied for the detection of exogenous and endogenous ROS in live cells as well as in vivo ROS quantitation. The dual transition metal ions endow this probe efficient catalytic decomposition capabilities, and this sensing strategy broadens the application of UCNPs-based nanomaterials in the field of biological analysis and diagnosis.