Label free aptasensor for ochratoxin A detection using polythiophene-3-carboxylic acid

• Published in: Talanta (Oxford) 2018-08, Vol.185, p.513-519
• Main Authors: Zejli, H., Goud, K. Yugender, Marty, Jean Louis
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Aptamer; Chemical Sciences; Coffee samples; Food and Nutrition; Life Sciences; Ochratoxin A; Screen printed carbon electrodes
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2018.03.089

This work demonstrates the development of electrochemical aptasensor using ochratoxin A (OTA) aptamers. Different aptamer coupling strategies were tested using polythiophene-carboxylic acid (PT3C) and polypyrrole-3-carboxylic acid (PP3C). The best sensitivity was recorded by polythiophene-3-carboxylic acid (PT3C) on screen-printed carbon electrode (SPCE) to attain the direct detection of OTA. The quantification of OTA was achieved by using electrochemical impedance spectroscopy. A good dynamic range 0.125–2.5 ng ml−1 was obtained for OTA with limit of detection (LOD) 0.125 ng ml−1 and Limit of quantification (LOQ) 0.3 ng ml−1 respectively. The good reproducibility was recorded with RSD% of 3.68. The obtained straight line equation was y = 0.4061 × + 1.03, r = 0.99. For real sample applications, the developed aptasensors were demonstrated in coffee samples. The aptasensor displayed good recovery values in the range 88–89%, thus exhibited the effectiveness of proposed aptasensor for such complex matrices. •Immobilisation of aptamer by polythiophene-3 -carboxylic on SPCE.•Good performance in term of sensitivity and limit of detection.•An application of this aptasensor in a coffee samples.