Ni–Co Layered Double Hydroxide Nanocage-Mediated Reactive Oxygen Species Generation for Ultrasensitive Chemiluminescent Detection of Dopamine

Chemiluminescence (CL), which generates stable and luminous light emissions, is vital for accurate dopamine (DA) detection. Additionally, catalysts play an essential role in the CL system's performance. Herein, nickel-cobalt layered double hydroxide hollow nanocages (Ni-Co LDHs) with peroxidase catalytic activities are well synthesized with zeolitic imidazolate framework-67 (ZIF-67) nanocrystals serving as the self-sacrificing templates. The metal active sites found on the host layer of Ni-Co LDHs and the low redox potential of Co³⁺/Co²⁺ enable good affinity towards hydrogen peroxide (H₂O₂). Decomposing H₂O₂ generates significant amounts of reactive oxygen species (ROS), which, when utilized in a luminol-based system, enhance the CL response by an impressive factor of 952 times. Dopamine remarkably quenches the produced CL of the luminol/H₂O₂/Ni-Co LDHs. Based on the concentration-dependent quenching of the intense luminol/H₂O₂/Ni-Co LDH signal by dopamine, we establish a sensitive and selective CL method for detecting DA in the linear range of 5-1000 nM, achieving a low limit of detection of 1.51 nM. The developed method's practical efficacy was verified by determining dopamine in human serum. This study demonstrates that Ni-Co LDHs embrace great prospects for analytical method development.