title: An electrochemical aptasensor for thrombin detection based on the recycling of exonuclease III and double-stranded DNA-templated copper nanoparticles assisted signal amplification.
abstract: In this paper, we report an improved electrochemical aptasensor based on exonuclease III and double-stranded DNA (dsDNA)-templated copper nanoparticles (CuNPs) assisted signal amplification. In this sensor, duplex DNA from the hybridization of ligated thrombin-binding aptamer (TBA) subunits and probe DNA can act as an effective template for the formation of CuNPs on the electrode surface, so copper ions released from acid-dissolution of CuNPs may catalyze the oxidation of ο-phenylenediamine to produce an amplified electrochemical response. In the presence of thrombin, a short duplex domain with four complementary base pairs can be stabilized by the binding of TBA subunits with thrombin, in which TBA subunit 2 can be partially digested from 3' terminal with the cycle of exonuclease III, so the ligation of TBA subunits and the subsequent formation of CuNPs can be inhibited. By electrochemical characterization of dsDNA-templated CuNPs on the electrode surface, our aptasensor can display excellent performances for the detection of thrombin in a broad linear range from 100 fM to 1 nM with a low detection limit of 20.3 fM, which can also specially distinguish thrombin in both PBS and serum samples. Therefore, our aptasensor might have great potential for clinical diagnosis of biomarkers in the future.
authors: Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, PR China.
authors: Jing
authors: J
authors: Zhao
authors: Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, PR China.
authors: Meiling
authors: M
authors: Xin
authors: Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, PR China.
authors: Ya
authors: Y
authors: Cao
authors: Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China. Electronic address: yinym_njmu@163.com.
authors: Yongmei
authors: Y
authors: Yin
authors: Department of Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, PR China.
authors: Yongqian
authors: Y
authors: Shu
authors: Institute of Genetic Engineering of Southern Medical University, Guangzhou 510515, PR China.
authors: Wenli
authors: W
authors: Ma
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000295:instrumentation; D004566:Electrodes; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D003300:Copper; D004247:DNA; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; D013917:Thrombin
keywords: Double-stranded DNA-templated copper nanoparticles; Electrochemical aptasensor; Exonuclease III; Signal amplification; Thrombin