Selective PQQPFPQQ Gluten Epitope Chemical Sensor with a Molecularly Imprinted Polymer Recognition Unit and an Extended-Gate Field-Effect Transistor Transduction Unit

Authors:
Publisher website
Google Scholar
Abstract
A molecularly imprinted polymer (MIP) recognition system was devised for selective determination of an immunogenic gluten octamer epitope, PQQPFPQQ. For that, a thin MIP film was devised, guided by DFT calculations, and then synthesized to become the chemosensor recognition unit. Bis(bithiophene)-based cross-linking and functional mono-mers were used for this synthesis. An EG-FET was used as the transduction unit. The EG-FET gate surface was coated with the PQQPFPQQ-templated MIP film, by electropolymerization, to result in a complete chemosensor. XPS analysis confirmed the presence of the PQQPFPQQ epitope, and its removal from the MIP film. The chemosensor selectively discriminated between the octamer analyte and another peptide of the same number of amino acids but with mismatched two of them (PQQQFPPQ). The chemosensor was validated with respect to both the PQQPFPQQ analyte and a real gluten extract from semolina flour. It was capable to determine PQQPFPQQ in the concentration range of 0.5-45 ppm with the limit of detection, LOD=0.11 ppm. Moreover, it was capable to determine gluten in real samples in the concentration range of 4-25 ppm with LOD=4 ppm, which is a value sufficient for discriminating between gluten-free and non-(gluten free) food products. The gluten content in semolina flour determined with the chemosensor well correlated with that determined with a commercial ELISA gluten kit. The Langmuir, Freundlich, and Langmuir-Freundlich isotherms were fitted to the epitope sorption data. The sorption parameters determined from these isotherms indicated that the imprinted cavities were quite homogeneous and that the epitope analyte was chemisorbed in them.
Funding Information
  • Fundacja na rzecz Nauki Polskiej (START 23.2017)
  • H2020 Marie Sklodowska-Curie Actions (752438)
  • Narodowe Centrum Nauki (2014/15/B/NZ7/01011, 2013/11/N/ST5/01907)

This publication has 39 references indexed in Scilit: