An off-on-off electrochemiluminescence approach for ultrasensitive detection of thrombin.
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 Eu(3+)-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 Förster-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.
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Li
L
Deng
Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080, China.
Ying
Y
Du
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China. Electronic address: xujj@nju.edu.cn.
Jing-Juan
JJ
Xu
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Hong-Yuan
HY
Chen
D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D019187:Cadmium Compounds / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods; D005063:Europium / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D049408:Luminescent Agents / Q000737:chemistry*; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods; D053768:Metal Nanoparticles / Q000737:chemistry; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D013917:Thrombin / Q000032:analysis*
D052157:Aptamers, Nucleotide; D019187:Cadmium Compounds; D049408:Luminescent Agents; D013440:Sulfides; C034939:cadmium sulfide; C081676:thrombin aptamer; D005063:Europium; D006046:Gold; D013917:Thrombin
Electrochemiluminescence; Eu(3+)-doped CdS nanocrystals; Gold nanoparticles; Resonance energy transfer; Thrombin binding aptamer