Single-Walled Carbon Nanotube-Coated Flexible and Soft Screen-Printed Electrochemical Biosensor for Ochratoxin A Detection

Ochratoxin A (OTA) is one of the most widely known and highly toxic types of mycotoxins, able to contaminate different food products and result in serious health problems for consumers. It is therefore important to detect OTA using fast, simple and reliable techniques. In this work, bendable and stretchable selective OTA biosensors were screen-printed on Polyethylene terephthalate (PET) and Poly(dimethylsiloxane) (PDMS), respectively. The working electrodes (WE) were coated with single-walled carbon nanotubes (SWCNTs) and then immobilized with anti-OTA antibodies. The biosensor showed selectivity to OTA compared to another interfering mycotoxin. Furthermore, they were mechanically stable to 5000 cycles of bending down to 7.5 mm diameter, as well as to 300 iterations of stretching up to 33.5%. The presented biosensors have a linear detection range of 0.01 - 1 ng/mL with a limit of detection (LOD) of 0.08 and 0.13 ng/mL in grape juice for the bendable and stretchable biosensor, respectively. These values are one order of magnitude lower than the maximum allowable limits set by the European Union for both grape juice and wine.