title: Ultrasensitive electrochemical detection for thrombin using hybridization chain reaction with enzyme-amplification.
abstract: In this work, a new electrochemical aptasensor using hybridization chain reaction (HCR) for signal amplification was developed for highly sensitive detection of thrombin. The sandwich system of aptamer/thrombin/aptamer-primer complex was fabricated as the sensing platform. As the initiator strands, aptamer-primer complex could propagate a chain reaction of hybridization events between the two hairpin probes, and whether long nicked DNA polymers could be formed on the modified electrode. Then the biotin-labeled dsDNA polymers could introduce numerous avidin-labeled horseradish peroxidase (HRP), resulting in significantly amplified electrochemical signal through the electrocatalysis of HRP. On the basis of the enzymatic oxidization of Fe(2+) by H2O2 to yield Fe(3+), the imaging of thrombin was detected by the reduction current of Fe(3+) with the scanning electrochemical microscopic tip. The electrochemical signals had a good linear with logarithm of thrombin concentration in the range from 1.0 fM to 100 fM, reaching a detection limit of thrombin as low as 0.04 fM. In addition, the proposed strategy exhibited excellent specificity and was successfully applied in real sample assay which demonstrated the potential application in clinical diagnostics.
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
authors: Weiling
authors: W
authors: Song
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
authors: Xuxu
authors: X
authors: Xie
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
authors: Wenbo
authors: W
authors: Sun
authors: Shandong Provincial Key Laboratory of Detection Technology for Tumor Makers, Linyi University, Linyi 276005, PR China.
authors: Ningbo
authors: N
authors: Zhang
authors: Key Laboratory of Sensor Analysis of Tumor Marker, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China. Electronic address: lichunxiang76@126.com.
authors: Chunxiang
authors: C
authors: Li
mesh_terms: D055664:Electrochemical Techniques; D004566:Electrodes; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006801:Humans; D009693:Nucleic Acid Hybridization; D013917:Thrombin / Q000032:analysis*
chemical_list: D006735:Horseradish Peroxidase; D013917:Thrombin
keywords: Aptasensor; Hybridization chain reaction; Thrombin; Topographic imaging