Synthesis of highly selective and sensitive magnetic targeted nanoprobe for Cr3+ detection in aqueous solution and its application in living cell imaging

The magnetic targeted probes based on rhodamine B (RB)-polyethylene glycol dicarboxylic acid (PEG)-polyacrylic acid (PAA)-comodified Fe3O4 nanoparticles (RB-PEG-PAA-MNPs) have been successfully synthesized for Cr3+ detection. The RB-PEG-PAA-MNPs have many favorable properties, including biocompatibility, robustness and magnetic response. Importantly, the fluorescence changes of the probes are remarkably specific for Cr3+ in the presence of other cations, and the limit of detection (LOD) for Cr3+ in MeOH-H2O (3:2, v:v, pH 7.4) solution is lower (0.131 μM) than the value of the U.S. EPA, which meet the selective and sensitive requirements for practical application. Furthermore, the experiments of RB-PEG-PAA-MNPs for monitoring Cr3+ inside HUVE cells reveal that the probes have low cytotoxicity and can effectively detect Cr3+ in a short time. In general, all the results presented in this study show that the proposed probes have significant potential for targeted detection of Cr3+ in many environmental and biomedical applications.