Chemiluminescence of the Ce(IV)/CDP-Star System Based on the Phosphatase-like Activity of Ce(IV) Ions.

The phosphatase-like activity of Ce(IV) ions was applied for chemiluminescence (CL) analysis for the first time. Ce(IV) can catalyze the hydrolysis of CDP-star, which is a phosphatase substrate, to produce strong CL emission. The CL performance of the Ce(IV)/CDP-star system can be significantly improved by the addition of ionic liquids. In the presence of 1-butyl-3-methylimidazolium tetrafluoroborate, the selective and sensitive CL detection of Ce(IV) ions was achieved with a detection limit of 460 nM. The proposed CL system was also used for the detection of ascorbic acid and ClO-. It is based on the phenomenon that Ce(IV) can catalyze the hydrolysis of CDP-star, while Ce(III) cannot. The introduction of reductive ascorbic acid into the mixture of Ce(IV)/CDP-star can turn off the CL signal, while the addition of oxidative ClO- into the solution of Ce(III)/CDP-star can turn on the CL emission. Finally, Ce(IV)/CDP-star CL was successfully applied for evaluating the total antioxidant capacity in commercial fruit juice samples.

Ionic liquid-assisted chemiluminescent immunoassay of prostate specific antigen using nanoceria as an alkaline phosphatase-like nanozyme label.

An alkaline phosphatase-like nanozyme was applied for an immunoassay for the first time. By using nanoceria as the alkaline phosphatase-like catalytic label and CDP-star as the substrate, the chemiluminescent detection of prostate specific antigen was demonstrated. More importantly, the addition of ionic liquid can significantly increase the sensitivity of the immunoassay. With the aid of ionic liquid, an order of magnitude improvement in the sensitivity was achieved with a detection limit of 53 fg mL-1.

The phosphatase-like activity of zirconium oxide nanoparticles and their application in near-infrared intracellular imaging.

In this study, the phosphatase mimetic activity of zirconium oxide nanoparticles (ZrO2 NPs) has been demonstrated. They can effectively catalyze the dephosphorylation of a series of commercial fluorogenic and chromogenic substrates of natural phosphatases. Compared with natural phosphatases, ZrO2 NPs possess several advantages such as low cost, facile preparation procedures, and high stability in a broader pH range or at high temperatures. In addition, the activity of ZrO2 NPs toward some important biomolecules was investigated. The ZrO2 NPs can catalyze the dephosphorylation of ATP and o-phospho-l-tyrosine, but they cannot react with DNA strands. These data are important for the further bio-related applications of ZrO2 NPs. Finally, the potential application of ZrO2 NPs in intracellular imaging is also demonstrated by using a near-infrared fluorescent substrate of alkaline phosphatase.