Highly sensitive chemiluminescent sensing of intracellular Al based on the phosphatase mimetic activity of cerium oxide nanoparticles.

Nanomaterials with enzyme-like characteristics (also called nanozymes) have attracted increasing attention in the area of analytical chemistry. Nevertheless, most of the nanozymes used for analytical applications are oxidoreductase mimics, and their enzyme-like activities are usually demonstrated by using chromogenic and/or fluorogenic substrates. Herein, the phosphatase mimetic activity of cerium oxide nanoparticles (nanoceria) was investigated by using CDP-star as the chemiluminescent (CL) substrate. Interestingly, we found that the phosphatase mimetic activity of nanoceria can be remarkably inhibited by the addition of Al. Based on this finding, a highly sensitive and selective CL method for Al detection is proposed. The CL intensity of the nanoceria/CDP-star system decreased with the increasing Al concentrations in the range from 30 nM to 3.5 μM. A detection limit as low as 10 nM was obtained. Finally, the CL detection of intracellular Al was achieved, demonstrating the utility of the CL method in complex biological samples.