Fluorescent Disulfide-functional Coordination Polymers for Sensitive Detection of Hydrogen Peroxide

A new type of fluorescent coordination polymer (NCP_Cd) based on disulfide carboxylate ligand was prepared by using one-pot synthesis for sensitive detection of reactive oxygen species (ROS). With the reaction between NCP_Cd and ROS, the morphology of the NCP_Cd was transformed from nanorods to hexagon particles, then broken into nano-fragments. Meanwhile, the fluorescence of NCP_Cd (at 421 nm) was quenched accordingly. For designing the highly sensitive probe for ROS, Rhodamine 6G (R6G) was doped in NCP_Cd. In the presence of ROS, the fluorescence of NCP_Cd moiety at 421 nm was quenched, but the R6G moiety was released from the broken nanorods and the fluorescence at 555 nm from R6G moiety was recovered. The R6G doped NCP_Cd (NCP_Cd-R) can be used as a highly sensitive and selective probe for hydrogen peroxide (H₂O₂) with detection limit of 12.4 nM. Moreover, the NCP_Cd-R was further extended to the glucose sensing combined with glucose oxidase (GOx) to oxidate glucose and generate H₂O₂, demonstrating the potential for practical applications.