Chemilumineacent/Electrochemical Detection Of Telomerase Activity In Cancer Cells

Compared to the complex operation, high cost, low sensitivity and precision of the early diagnosis of tumour, Here we described a new electrochemistry biosensor based on several amplifying techniques, including gold nanoparticle amplification technology, magnetic bead separation technology, nucleic acid hybridization technology and bio-bar-code technology. In the presence of target cells, our method has a simple operation, high sensitivity and selection. This paper contained two chapters:1 An ECL biosensor for highly sensitive detection of telomerase was developed based on bio-bar-code amplification technology. The telomerase was extracted from HeLa cell, with the telomerase substrate (TS) primer, an expanded reaction was developed, the products of the reaction hybridized with the capture DNA on the electrode and the other end of the product hybridized with the signal DNA on DNA-gold nanoparticle complexs to form a complex with a "sandwich" structure, the bar-code DNA on the DNA-gold nanoparticle complexes hybridized with the complementary DNA. Modified electrode immersed in the buffer solution containing [Ru(phen)2dppz]2+, [Ru(phen)2dppz]2+ intercalated with the double-stranded DNA, by generating electrochemiluminescent detection of telomerase activity signal, the method does not require PCR amplification can be detected in the extract of 1000 HeLa cells the telomerase activity.2 Based on the formation of G-quadruplex-hemin DNAzyme, a chemiluminescence method for sensitive detection of human telomerase activity was developed. In the presence of telomerase, the telomerase substrate (TS) primer elongated and a long single-strand DNA containing the telomere repeat units (TTAGGG) was formed. When K+ was introduced, the telomere repeat units could form G-quadruplex and then combined with hemin to form DNAzymes which could stimulate the generation of chemiluminescence (CL) in the presence of luminol and H2O2. The amount of telomerase extension product was controlled by the content of telomerase extracted from HeLa cells, so the amount of DNAzymes and the intensity of chemiluminescence signal were all related to the number of HeLa cells. Using this simple method, the telomerase activity extracted from 100 cultured cancer cells could be detected without the polymerase chain reaction (PCR) amplification of telomerase elongated product.