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Updated: Oct 29, 2025
Phthalic Acid Ester-Binding DNA Aptamer Selection, Characterization, and Application to an Electrochemical Aptasensor
Published on: March 21, 2018
Biosensors for the detection of organophosphate exposure by a new diethyl thiophosphate-specific aptamer
Napachanok Mongkoldhumrongkul Swainson1, Pongsakorn Aiemderm1, Chonnikarn Saikaew2,3
1Department of Biochemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Bangkok, 10900, Chatuchak, Thailand.
Objective:
An aptamer specifically binding to diethyl thiophosphate (DETP) was constructed and incorporated in an optical sensor and electrochemical techniques to enable the specific measurement of DETP as a metabolite and a biomarker of organophosphate exposure.
Results:
A DETP-bound aptamer was selected from the library using capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX). A colorimetric method revealed that the aptamer had the highest affinity for DETP, with a mean Kd value (± SD) of 0.103 ± 0.014 µM. The docking results and changes in resistance showed that the selectivity of the aptamer for DETP was higher than that for the similar structures of dithiophosphate (DEDTP) and diethyl phosphate (DEP). The altered amplitude of cyclic voltammetry showed a linear range of DETP detection covering 0.0001-10 µg/ml with a limit of detection of 0.007 µg/ml. The recovery value of a real sample of pH 7 was 97.2%.
Conclusions:
The current method showed great promise in using the DETP-specific aptamer to detect the exposure history to organophosphates by measuring their metabolites, although degradation of organophosphate parent compounds might occur.
