title: Dual signal amplification for highly sensitive electrochemical detection of uropathogens via enzyme-based catalytic target recycling.
abstract: We report an ultrasensitive electrochemical approach for the detection of uropathogen sequence-specific DNA target. The sensing strategy involves a dual signal amplification process, which combines the signal enhancement by the enzymatic target recycling technique with the sensitivity improvement by the quantum dot (QD) layer-by-layer (LBL) assembled labels. The enzyme-based catalytic target DNA recycling process results in the use of each target DNA sequence for multiple times and leads to direct amplification of the analytical signal. Moreover, the LBL assembled QD labels can further enhance the sensitivity of the sensing system. The coupling of these two effective signal amplification strategies thus leads to low femtomolar (5fM) detection of the target DNA sequences. The proposed strategy also shows excellent discrimination between the target DNA and the single-base mismatch sequences. The advantageous intrinsic sequence-independent property of exonuclease III over other sequence-dependent enzymes makes our new dual signal amplification system a general sensing platform for monitoring ultralow level of various types of target DNA sequences.
authors: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors: Jiao
authors: J
authors: Su
authors: Haijie
authors: H
authors: Zhang
authors: Bingying
authors: B
authors: Jiang
authors: Huzhi
authors: H
authors: Zheng
authors: Yaqin
authors: Y
authors: Chai
authors: Ruo
authors: R
authors: Yuan
authors: Yun
authors: Y
authors: Xiang
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D015342:DNA Probes / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics; D055664:Electrochemical Techniques; D006801:Humans; D021141:Nucleic Acid Amplification Techniques; D045663:Quantum Dots; D056689:Uropathogenic Escherichia coli / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D015342:DNA Probes; D004269:DNA, Bacterial