title: Sensitive electrochemical detection of telomerase activity using spherical nucleic acids gold nanoparticles triggered mimic-hybridization chain reaction enzyme-free dual signal amplification.
abstract: We report an electrochemical sensor for telomerase activity detection based on spherical nucleic acids gold nanoparticles (SNAs AuNPs) triggered mimic-hybridization chain reaction (mimic-HCR) enzyme-free dual signal amplification. In the detection strategy, SNAs AuNPs and two hairpin probes were employed. SNAs AuNPs as the primary amplification element, not only hybridized with the telomeric repeats on the electrode to amplify signal but also initiated the subsequent secondary amplification, mimic-hybridization chain reaction of two hairpin probes. If the cells' extracts were positive for telomerase activity, SNAs AuNPs could be captured on the electrode. The carried initiators could trigger an alternative hybridization reaction of two hairpin probes that yielded nicked double helices. The signal was further amplified enzyme-free by numerous hexaammineruthenium(III) chloride ([Ru(NH3)6](3+), RuHex) inserting into double-helix DNA long chain by electrostatic interaction, each of which could generate an electrochemical signal at appropriate potential. With this method, a detection limit of down to 2 HeLa cells and a dynamic range of 10-10,000 cells were achieved. Telomerase activities of different cell lines were also successfully evaluated.
authors: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University , Nanjing 210093, People's Republic of China.
authors: Wen-Jing
authors: WJ
authors: Wang
authors: Jing-Jing
authors: JJ
authors: Li
authors: Kai
authors: K
authors: Rui
authors: Pan-Pan
authors: PP
authors: Gai
authors: Jian-Rong
authors: JR
authors: Zhang
authors: Jun-Jie
authors: JJ
authors: Zhu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D009693:Nucleic Acid Hybridization / Q000379:methods*; D009696:Nucleic Acids / Q000737:chemistry*; D017975:Ruthenium Compounds / Q000737:chemistry; D019098:Telomerase / Q000378:metabolism*
chemical_list: D009696:Nucleic Acids; D017975:Ruthenium Compounds; C031584:hexammineruthenium; D006046:Gold; C509186:TERT protein, human; D019098:Telomerase