High-entropy metal-organic-framework nanosheets enhanced luminol/H2O2 chemiluminescence for ultrasensitive dopamine detection

A chemiluminescence (CL) system with high intensity and long-lasting emission is crucial for accurate CL measurements. The luminol/hydrogen peroxide (H 2 O 2 ) CL system has recently attracted significant attention. However, the CL emission from the luminol/H 2 O 2 system is typically weak, which limits its application for quantitative measurements. In this study, we synthesized a high-entropy metal–organic framework nanosheet (HE-MOFs) containing five homogeneous and nearly equally dispersed metal ions using a solution-phase strategy at room temperature. The resulting HE-MOFs exhibited exceptional peroxidase-mimicking catalytic activity. Their intrinsic peroxidase-like properties allowed HE-MOFs to efficiently catalyze H 2 O 2 , generating reactive oxygen species (ROS) and producing a strong, efficient, and stable CL emission in the luminol/H 2 O 2 /HE-MOFs system. The remarkable enhancement of CL emission can be attributed to the synergistic effects of the multi-metal ions in the unique crystal structure of HE-MOFs. Consequently, we developed a fast, sensitive, and selective luminol/H 2 O 2 /HE-MOFs CL sensor to detect dopamine (DA), leveraging the potential inhibitory effect of DA on CL emission. This sensor effectively detected dopamine and demonstrated good linearity over a 10–500 nM concentration range, with a low detection limit (LOD) of 3.90 nM (S/N = 3). As a proof of concept, we applied the method to detect DA in real samples, achieving excellent recoveries ranging from 95 % to 105 % (RSD < 1.19 %, n = 3). Our findings provide a new perspective on designing high-entropy-based MOFs nanozymes and lay the groundwork for developing highly sensitive CL biosensors for real-time bioassays.