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An Electrochemical Aptasensor for Detection of Thrombin based on Target Protein‐induced Strand Displacement
Author(s) -
Fan Hao,
Chang Zhu,
Xing Rong,
Chen Miao,
Wang Qingjiang,
He Pingang,
Fang Yuzhi
Publication year - 2008
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200804281
Subject(s) - aptamer , electrochemistry , thrombin , electrode , detection limit , lysozyme , chemistry , nanoparticle , biosensor , combinatorial chemistry , materials science , nanotechnology , chromatography , biochemistry , microbiology and biotechnology , biology , platelet , immunology
A sensitive electrochemical aptasensor for detection of thrombin based on target protein‐induced strand displacement is presented. For this proposed aptasensor, dsDNA which was prepared by the hybridization reaction of the immobilized probe ssDNA (IP) containing thiol group and thrombin aptamer base sequence was initially immobilized on the Au electrode by self‐assembling via AuS bind, and a single DNA labeled with CdS nanoparticles (DP‐CdS) was used as a detection probe. When the so prepared dsDNA modified Au electrode was immersed into a solution containing target protein and DP‐CdS, the aptamer in the dsDNA preferred to form G‐quarter structure with the present target protein resulting that the dsDNA sequence released one single strand and returned to IP strand which consequently hybridized with DP‐CdS. After dissolving the captured CdS particles from the electrode, a mercury‐film electrode was used for electrochemical detection of these Cd 2+ ions which offered sensitive electrochemical signal transduction. The peak current of Cd 2+ ions had a good linear relationship with the thrombin concentration in the range of 2.3×10 −9 –2.3×10 −12 mol/L and the detection limit was 4.3×10 −13 mol/L of thrombin. The detection was also specific for thrombin without being affected by the coexistence of other proteins, such as BSA and lysozyme.