Fast on-site detection of Ochratoxin A by the graphene-based field-effect transistors

Mycotoxins are a widespread contaminant in food and feed produced as second
metabolites of Aspergillus and Penicillium genera microfungi [1,2]. Ochratoxin A is a
mycotoxin that can be found in a wide range of food, from cereals to wine, which is why
it has to be regularly monitored by different standardized methods. To date, methods
like high-performance liquid chromatography-mass spectrometry or enzyme-linked
immunosorbent assay (ELISA) are very prominent tools for Ochratoxin A monitoring, but
they require highly trained and qualified staff, as well as controlled laboratory
environment, which hinders the in-field use and do not promote low-cost and easy-to-
use current and future demands [3,4]. In this research, we report on a specific
biosensing tool for the detection of Ochratoxin A, based on lithography-fabricated array
of graphene field-effect transistors (G-FETs) on a single silicon chip. G-FETs are
assembled with specific aptamers, used as a recognition element on the graphene
channel as a transducer deposited via pyrene-based linker (Figure 1). The biosensor
showed high sensitivity to Ochratoxin A with the limit of detection of 1.4 pM and a
response time of the order of magnitude 10 s. The biosensor is tested on a real red
wine samples with a response time of 50 s, showing promising results for future
research.