Electrochemiluminescent aptamer biosensor for the determination of ochratoxin A at a gold-nanoparticles-modified gold electrode using N-(aminobutyl)-N-ethylisoluminol as a luminescent label.
A highly selective electrochemiluminescent biosensor for the detection of target nephrotoxic toxin, ochratoxin A (OTA), was developed using a DNA aptamer as the recognition element and N-(4-aminobutyl)-N-ethylisoluminol (ABEI) as the signal-producing compound. The electrochemiluminescent aptamer biosensor was fabricated by immobilizing aptamer complementary DNA 1 sequence onto the surface of a gold-nanoparticle (AuNP)-modified gold electrode. ABEI-labeled aptamer DNA 2 sequence hybridized to DNA 1 and was utilized as an electrochemiluminescent probe. A decreased electrochemiluminescence (ECL) signal was generated upon aptamer recognition of the target OTA, which induced the dissociation of DNA 2 (ABEI-labeled aptamer electrochemiluminescent probe) from DNA 1 and moved it far away from the electrode surface. Under the optimal conditions, the decreased ECL intensity was proportional to an OTA concentration ranging from 0.02 to 3.0 ng mL(-1), with a detection limit of 0.007 ng mL(-1). The relative standard deviation was 3.8% at 0.2 ng mL(-1) (n = 7). The proposed method has been applied to measure OTA in naturally contaminated wheat samples and validated by an official method. This work demonstrates the combination of a highly binding aptamer with a highly sensitive ECL technique to design an electrochemiluminescent biosensor, which is a very promising approach for the determination of small-molecule toxins.
Wang
Zhouping
Z
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China. wangzp1974@hotmail.com
Duan
Nuo
N
Hun
Xu
X
Wu
Shijia
S
D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D049449:Luminescence; D008163:Luminescent Measurements / Q000295:instrumentation* / Q000379:methods; D008165:Luminol / Q000031:analogs & derivatives* / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D009793:Ochratoxins / Q000032:analysis*
D052157:Aptamers, Nucleotide; D009793:Ochratoxins; C025589:ochratoxin A; D008165:Luminol; C031912:6-(N-(4-aminobutyl)-N-ethyl)amino-2,3-dihydrophthalazine-1,4-dione; D006046:Gold