Jump to main content
Jump to site search


A new photoelectrochemical biosensor for ultrasensitive determination of nucleic acid based on three-stage cascade signal amplification strategy

Abstract

The sensitive and specific determination of nucleic acids is very important in clinical diagnosis and biological studies. In this work, an ultrasensitive photoelectrochemical (PEC) biosensor has been developed for DNA detection based on “signal−on” sensing strategy and three−stage cascade signal amplification method (catalytic hairpin assembly (CHA), hybridization chain reaction (HCR) and alkaline phosphatase (ALP)−triggered in-situ generation of ascorbic acid (AA)). Here, the CHA hairpin 1 (CHA−HP1) is opened by the target DNA (T−DNA) owing to the hybridization between T−DNA and CHA−HP1, then the opened CHA−HP1 hybridizes with the CHA hairpin 2 (CHA−HP2) to displace the T−DNA, generating CHA−HP1/CHA−HP2 complex. The displaced T−DNA triggers the next cycle of CHA, resulting in the generation of numerous CHA−HP1/CHA−HP2 complexes. Subsequently, one end of the CHA−HP1/CHA−HP2 complex hybridizes with the capture DNA immobilized on the indium tin oxide/TiO2/CdS:Mn electrode. After the introduction of dual−biotin labeled HCR hairpin 1 (HCR−HP1−Bio) and dual−biotin labeled HCR hairpin 2 (HCR−HP2−Bio), the other end of the CHA−HP1/CHA−HP2 complex opens the HCR−HP1−Bio. The opened HCR−HP1−Bio triggers the HCR reaction between HCR−HP1−Bio and HCR−HP2−Bio, leading to form long nicked duplex DNA structures. The dual-biotin modified HCR-hairpins can anchor more streptavidin−ALP to catalyze 2−phospho−L−ascorbic acid trisodium salt to yield more AA, leading to larger PEC response. The proposed PEC biosensor shows superior analytical performance for T−DNA detection with a linear response range from 0.1 fM to 100 pM and a detection limit of 0.052 fM, and may provide a powerful biosensing platform for bioanalysis and early disease diagnosis.

Back to tab navigation

Supplementary files

Publication details

The article was received on 02 Apr 2018, accepted on 10 May 2018 and first published on 12 May 2018


Article type: Paper
DOI: 10.1039/C8AN00609A
Citation: Analyst, 2018, Accepted Manuscript
  •   Request permissions

    A new photoelectrochemical biosensor for ultrasensitive determination of nucleic acid based on three-stage cascade signal amplification strategy

    E. Xiong, X. Yan, X. Zhang, Y. Li, R. Yang, L. Meng and J. Chen, Analyst, 2018, Accepted Manuscript , DOI: 10.1039/C8AN00609A

Search articles by author

Spotlight

Advertisements