Dendrimers: New tool for enhancement of electrochemiluminescent signal

Electrochemiluminescence Sensor Based on CeO2 Nanocrystalline for Hg2+ Detection in Environmental Samples

The excessive concentration of heavy-metal mercury ions (Hg2+) in the environment seriously affects the ecological environment and even threatens human health. Therefore, it is necessary to develop rapid and low-cost determination methods to achieve trace detection of Hg2+. In this paper, an Electrochemiluminescence (ECL) sensing platform using a functionalized rare-earth material (cerium oxide, CeO2) as the luminescent unit and an aptamer as a capture unit was designed and constructed. Using the specific asymmetric matching between Hg2+ and thymine (T) base pairs in the deoxyribonucleic acid (DNA) single strand, the "T-Hg-T" structure was formed to change the ECL signal, leading to a direct and sensitive response to Hg2+. The results show a good linear relationship between the concentration and the response signal within the range of 10 pM-100 µM for Hg2+, with a detection limit as low as 0.35 pM. In addition, the ECL probe exhibits a stable ECL performance and excellent specificity for identifying target Hg2+. It was then successfully used for spiked recovery tests of actual samples in the environment. The analytical method solves the problem of poor Hg2+ recognition specificity, provides a new idea for the efficient and low-cost detection of heavy-metal pollutant Hg2+ in the environment, and broadens the prospects for the development and application of rare-earth materials.

A redox-mediator pathway for enhanced multi-colour electrochemiluminescence in aqueous solution

The classic and most widely used co-reactant electrochemiluminescence (ECL) reaction of tris(2,2'-bipyridine)ruthenium(ii) ([Ru(bpy)3]2+) and tri-n-propylamine is enhanced by an order of magnitude by fac-[Ir(sppy)3]3- (where sppy = 5'-sulfo-2-phenylpyridinato-C 2,N), through a novel 'redox mediator' pathway. Moreover, the concomitant green emission of [Ir(sppy)3]3-* enables internal standardisation of the co-reactant ECL of [Ru(bpy)3]2+. This can be applied using a digital camera as the photodetector by exploiting the ratio of R and B values of the RGB colour data, providing superior sensitivity and precision for the development of low-cost, portable ECL-based analytical devices.

Novel Ce(III)-Metal Organic Framework with a Luminescent Property To Fabricate an Electrochemiluminescence Immunosensor

We designed a novel luminescent metal-organic framework (MOF) named Ce-TCPP-LMOF (CTM) through a simple one-pot solvothermal method. CTM was synthesized by using the emerging electrochemiluminescent (ECL) material (4,4',4″,4‴-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) as the organic ligand and Ce(III) as the metal node. We found that CTM not only has the remarkable ability to emit light but also has a uniform "sandwich biscuit" shape and suitable nanoscale size, which are promising for further applications. We also applied CTM to construct a novel ECL immunosensor and achieve sensitive detection of the proprotein convertase subtilisin/kexin type 9 (PCSK9), a biomarker related to cardiovascular diseases. To further amplify the ECL signal of CTM, a novel dual-amplified signal strategy was established by inducing a polyamidoamine dendrimer (PAMAM) and gold nanoparticles (AuNPs). Importantly, we first proved that the ECL signal of the CTM/S₂O₈^2- system could be enhanced by the PAMAM electric field. As the electron transfer rate was accelerated by the AuNP layer, this ECL signal was further enhanced in AuNP-modified electrodes. The ECL immunosensor showed desirable performance for PCSK9 analysis within a detection range of 50 fg mL^-1 to 10 ng mL^-1 and a low limit of detection of 19.12 ± 2.69 fg mL^-1. Real sample detection suggested that the immunosensor holds great potential for analyzing clinical serum samples.

Graphitic Carbon Nitride Nanosheets as Co‐reactants for Tris(2,2′‐bipyridine)ruthenium(II) Electrochemiluminescence

The search for a biocompatible co‐reactant for tris(2,2′‐bipyridine)ruthenium(II) (Ru(bpy)32+) electrochemiluminescence (ECL) has attracted broad attention towards extending its application in the biomedical field. This work investigates the co‐reactant effect of graphitic carbon nitride nanosheets (CNNSs) on Ru(bpy)32+ ECL. CNNSs enhance the anodic ECL of Ru(bpy)32+ through the ECL interaction between Ru(bpy)33+ and the reductive intermediate of CNNSs, which are generated by either the direct electroreduction of CNNSs or the chemical/electrochemical oxidation of the amine groups on the CNNSs surface by Ru(bpy)33+. The finding may provide a new avenue for the development of self‐enhanced ECL probes and offer a new insight into revealing the surface feature of CNNSs.