Signal-On Dual-Potential Electrochemiluminescence Based on Luminol–Gold Bifunctional Nanoparticles for Telomerase Detection

• Published in: Analytical chemistry (Washington) 2014-04, Vol.86 (8), p.3834-3840
• Main Authors: Zhang, Huai-Rong, Wu, Mei-Sheng, Xu, Jing-Juan, Chen, Hong-Yuan
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Apoptosis - drug effects; Aptamers, Nucleotide - chemistry; Cadmium; Cadmium Compounds - chemistry; Deoxyribonucleic acid; DNA; DNA - isolation & purification; Electrochemical Techniques - methods; Electrochemiluminescence; Electrodes; Electroluminescence; Gold; Gold - chemistry; HL-60 Cells; Humans; Luminescent Measurements; Luminol - chemistry; Metal Nanoparticles - chemistry; Nanoparticles; Primers (coatings); Sulfides - chemistry; Surface Plasmon Resonance; Telomerase; Telomerase - analysis
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac403960g

Here, we report a novel type of signal-on dual-potential electrochemiluminescence (ECL) approach for telomerase detection based on bifunctionalized luminol–gold nanoparticles (L–Au NPs). In this approach, CdS nanocrystals (NCs) were first coated on glassy carbon electrode, and then thiol-modified telomerase primer was attached on CdS NCs via Cd–S bond. In the presence of telomerase and dNTPs, the primer could be extended. Telomerase primer would hybridize with its complementary DNA, and the extended part would hybridize with the capture DNA which was tagged with L–Au NPs. In the presence of coreactant H2O2, the L–Au NPs could not only enhance the ECL intensity of CdS NCs at −1.25 V (vs SCE) induced by the surface plasmon resonance (SPR) of Au NPs but also produce a new ECL signal at +0.45 V (vs SCE) that resulted from luminol in L–Au NPs. Both signals at two potentials increased with the increase of telomerase concentration. This method could be used to detect the telomerase from 100 to 9000 HL-60 cells and investigate the apoptosis of tumor cells. The ratio of the two signal increments (ΔECLLuminol/ΔECLCdS NCs), which showed a high consistency value for different numbers of cells, could be used to verify the reliability of tests. This dual-potential ECL strategy showed great promise in avoiding false positive or negative results in bioanalysis.