Glutamine-Binding Protein fromEscherichiacoliSpecifically Binds a Wheat Gliadin Peptide Allowing the Design of a New Porous Silicon-Based Optical Biosensor

Abstract

In this work, the binding of the recombinant glutamine-binding protein (GlnBP) from Escherichia coli to gliadin peptides, toxic for celiac patients, was investigated by mass spectrometry experiments and optical techniques. Mass spectrometry experiments demonstrated that GlnBP binds the following amino acid sequence: XXQPQPQQQQQQQQQQQQL, present only into the toxic prolamines. The binding of GlnBP to gliadin suggested us to design a new optical biosensor based on nanostructured porous silicon (PSi) for the detection of trace amounts of gliadin in food. The GlnBP, which acts as a molecular probe for the gliadin, was covalently linked to the surface of the PSi wafer by a proper passivation process. The GlnBP-gliadin interaction was revealed as a shift in wavelength of the fringes in the reflectivity spectrum of the PSi layer. The GlnBP, covalently bonded to the PSi chip, selectively recognized the toxic peptide. Finally, the sensor response to the protein concentration was measured in the range 2.0-40.0 microg/L and the sensitivity of the sensor was determined.

Applications of Monolayer‐Functionalized H‐Terminated Silicon Surfaces: A Review

“…Another type of sensor is based on a change in optical properties, e.g., optical‐reflectivity changes after DNA hybridization or protein–protein interactions . Trojan et al used the photoluminescence of porous silicon (see Section ) to build a sensor device .…”

Gliadins in Foods and the Electronic Tongue

“…In recent years, several optical and electrochemical biosensors, including immunosensors and aptasensors, have been developed to detect gliadin in food matrices, namely to evaluate gluten-free foods, since the amount of gluten must be lower than 20 mg/kg (or ppm), according to the legal requirements (Nassef et al, 2008;OJEU, 2009;Zeltner et al, 2009). De Stefano et al (2006 used an optical sensor with a recombinant glutamine-binding protein to detect traces of gluten in food.…”

Celiac disease diagnosis and gluten-free food analytical control

“…De Stefano and colleagues [114] proposed the development of a porous silicon-based (PSi) optical biosensor for the detection of trace amounts of gliadin using a recombinant glutamine-binding protein (GlnBP) from Escherichia coli as a molecular probe. The solutions containing the molecular probe and the analyte, peptic-tryptic (PT)-gliadin, were directly spotted on the sensor surface.…”