Highly enhanced electrochemiluminescence of novel gold/silica/CdSe-CdS nanostructures for ultrasensitive immunoassay of protein tumor marker.

The highly enhanced electrochemiluminescence from a novel hybrid gold/silica/CdSe-CdS quantum-dot nanostructure has been reported for the first time, and successfully applied to develop an ultrasensitive ECL immunosensor for the detection of a protein tumor marker, carcinoembryonic antigen.

Synthesis of novel chalcogenide 'lifebelts' and their electrogenerated chemiluminescence.

Novel chalcogenide lifebelts have been prepared by using a simple sacrificial template method, and their electrogenerated chemiluminescence properties were studied.

Electrogenerated chemiluminescence from CdS nanotubes and its sensing application in aqueous solution.

Electrogenerated chemiluminescence (ECL) of CdS nanotubes in aqueous solution and its sensing application were studied by entrapping the CdS nanotubes in carbon paste electrode. Two ECL peaks were observed at -0.9V (ECL-1) and -1.2V (ECL-2), respectively, when the potential was cycled between 0 and -1.6V. The electrochemically reduced nanocrystal species of CdS nanotubes could collide with the oxidized species in an annihilation process to produce the peak of ECL-1. The electron-transfer reaction between the reduced CdS nanocrystal species and oxidant coreactants such as S(2)O(8)(2-), H(2)O(2), and reduced dissolved oxygen led to the appearance of the ECL-2 peak. Based on the enhancing effect of H(2)O(2) on ECL-2 intensity, a novel CdS ECL sensor was developed for H(2)O(2) detection. The sensor exhibited a detection limit of 0.1muM and a linear range from 0.5muM to 0.01mM. The relative standard deviations of five replicate determinations of 5muM H(2)O(2) was 2.6%. In addition, the ECL spectrum in aqueous solution also exhibited two peaks at 500 and 640nm, respectively.

Studies on the interaction mechanism between hexakis(imidazole) manganese(II) terephthalate and DNA and preparation of DNA electrochemical sensor.

The interaction between hexakis(imidazole) manganese(II) terephthalate ([Mn(Im)(6)](teph).4H(2)O) and salmon sperm DNA in 0.2M pH 2.30 Britton-Robinson buffer solution was studied by fluorescence spectroscopy and cyclic voltammetry. Increasing fluorescence was observed for [Mn(Im)(6)](2+) with DNA addition, while quenching fluorescence phenomenon appeared for EB-DNA system when [Mn(Im)(6)](2+) was added. There were a couple quasi-reversible redox peaks of [Mn(Im)(6)](2+) from the cyclic voltammogram on the glassy carbon electrode. The peak current of [Mn(Im)(6)](2+) decreased with positive shift of the formal potential in the presence of DNA compared with that in the absence of DNA. All the experimental results indicate that [Mn(Im)(6)](2+) can bind to DNA mainly by intercalative binding mode. The binding ratio of the DNA-[Mn(Im)(6)](2+) association complex is calculated to be 1:1 and the binding constant is 4.44x10(3) M(-1). By using [Mn(Im)(6)](teph).4H(2)O as the electrochemical hybridization indicator, the DNA electrochemical sensor was prepared by covalent interaction and the selectivity of ssDNA modified electrode were described. The results demonstrate the use of electrochemical DNA biosensor in the determination of complementary ssDNA.