Journal
BIOSENSORS & BIOELECTRONICS
Volume 59, Issue -, Pages 58-63Publisher
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2014.03.012
Keywords
Electrochemiluminescence; Resonance energy transfer; Thrombin binding aptamer; Eu3+-doped CdS nanocrystals; Gold nanoparticles
Categories
Funding
- 973 Program [2012CB932600]
- National Natural Science Foundation of China [21135003, 21025522, 21105019]
- National Natural Science Funds for Creative Research Groups of China [21121091]
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This work demonstrates an aptasensor for ultrasensitive electrochemiluminescence (ECL) detection of thrombin based on an off-on-off approach. The system is composed of an Eu3+-doped CdS nanocrystals (CdS:Eu NCs) film on glassy carbon electrode (GCE) as ECL emitter. Then gold nanoparticles (AuNPs) labeled hairpin-DNA probe (ssDNA1) containing thrombin-binding aptamer (TBA) sequence was linked on the NCs film, which led to ECL quenching (off) as a result of Forster-resonance energy transfer (FRET) between the CdS:Eu NC film and the proximal AuNPs. Upon the occurrence of hybridization with its complementary DNA (ssDNA2), an ECL enhancement (on) occurred owing to the interactions of the excited CdS:Eu NCs with ECL-induced surface plasmon resonance (SPR) in AuNPs at large separation. Thrombin could induce ssDNA1 forming a G-quadruplex and cause the AuNPs to be close to CdS:Eu NCs film again, which resulted in an enhanced ECL quenching (off). This off-on-off' system showed a maximum 7.4-fold change of ECL intensity due to the configuration transformation of ssDNA1 and provides great sensitivity for detection of thrombin in a wide detection range from 50 aM to 1 pM. (C) 2014 Elsevier B.V. All rights reserved.
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