TY - JOUR
T1 - Label-free impedimetric aptasensor for ochratoxin-A detection using iridium oxide nanoparticles
AU - Rivas, Lourdes
AU - Mayorga-Martinez, Carmen C.
AU - Quesada-González, Daniel
AU - Zamora-Gálvez, Alejandro
AU - De La Escosura-Muñiz, Alfredo
AU - Merkoçi, Arben
PY - 2015/5/19
Y1 - 2015/5/19
N2 - © 2015 American Chemical Society. In this article, a novel aptasensor for ochratoxin A (OTA) detection based on a screen-printed carbon electrode (SPCE) modified with polythionine (PTH) and iridium oxide nanoparticles (IrO2 NPs) is presented. The electrotransducer surface is modified with an electropolymerized film of PTH followed by the assembly of IrO2 NPs on which the aminated aptamer selective to OTA is exchanged with the citrate ions surrounding IrO2 NPs via electrostatic interactions with the same surface. Electrochemical impedance spectroscopy (EIS) in the presence of the [Fe(CN)6]-3/-4 redox probe is employed to characterize each step in the aptasensor assay and also for label-free detection of OTA in a range between 0.01 and 100 nM, obtaining one of the lowest limits of detection reported so far for label-free impedimetric detection of OTA (14 pM; 5.65 ng/kg). The reported system also exhibits a high reproducibility, a good performance with a white wine sample, and an excellent specificity against another toxin present in such sample.
AB - © 2015 American Chemical Society. In this article, a novel aptasensor for ochratoxin A (OTA) detection based on a screen-printed carbon electrode (SPCE) modified with polythionine (PTH) and iridium oxide nanoparticles (IrO2 NPs) is presented. The electrotransducer surface is modified with an electropolymerized film of PTH followed by the assembly of IrO2 NPs on which the aminated aptamer selective to OTA is exchanged with the citrate ions surrounding IrO2 NPs via electrostatic interactions with the same surface. Electrochemical impedance spectroscopy (EIS) in the presence of the [Fe(CN)6]-3/-4 redox probe is employed to characterize each step in the aptasensor assay and also for label-free detection of OTA in a range between 0.01 and 100 nM, obtaining one of the lowest limits of detection reported so far for label-free impedimetric detection of OTA (14 pM; 5.65 ng/kg). The reported system also exhibits a high reproducibility, a good performance with a white wine sample, and an excellent specificity against another toxin present in such sample.
U2 - 10.1021/acs.analchem.5b00890
DO - 10.1021/acs.analchem.5b00890
M3 - Article
SN - 0003-2700
VL - 87
SP - 5167
EP - 5172
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 10
ER -