Dual Near-Infrared-Emissive Luminescent Nanoprobes for Ratiometric Luminescent Monitoring of ClO^– in Living Organisms

Abstract

The difficulty of near-infrared (NIR) ratiometric detection imaging lies in the lack of high-efficiency NIR probes and the overlapping interference between two emission peaks. To achieve more accurate detection in living organisms, dual NIR-emissive luminescent nanoprobes were designed under the same excitation at 808 nm. The Er3+ ion-doped nanoparticles were employed as a reference with their fluorescence emission at 1525 nm. Meanwhile, a cyanine dye molecule (Cy925) was combined on the surface of nanoparticles as the ClO– recognition site with its NIR emission at 925 nm. The ratiometric nanoprobe relied on the ratio of aforementioned two separated NIR peaks (I925nm/I1525nm), featuring deeper imaging penetration depth and low autofluorescence. This nanoprobe was verified to be sensitive and highly selective to ClO– through photoluminescence titration. The in vitro detection experiment developed reasonable work curves, guaranteeing that we can detect the change in concentration of ClO– in mice limbs with arthritis through in vivo imaging experiments.