Detection of Gliadin in Foods Using a Quartz Crystal Microbalance Biosensor That Incorporates Gold Nanoparticles

• Published in: Journal of agricultural and food chemistry Vol. 60; no. 26; pp. 6483 - 6492
• Main Authors: Chu, Pei-Tzu, Lin, Chih-Sheng, Chen, Wei-Jung, Chen, Chih-Feng, Wen, Hsiao-Wei
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 04.07.2012
• Subjects: antibodies; Biological and medical sciences; Biosensing Techniques; Biosensors; Biotechnology; chickens; detection limit; Electrodes; ethanol; Food Analysis - methods; Food industries; foods; Fundamental and applied biological sciences. Psychology; General aspects; gliadin; Gliadin - analysis; Gold; hypersensitivity; immunoglobulin Y; Metal Nanoparticles; Methods of analysis, processing and quality control, regulation, standards; Methods. Procedures. Technologies; nanoparticles; patients; quartz; Quartz Crystal Microbalance Techniques - methods; Various methods and equipments; wheat; gold nanoparticles; quartz crystal microbalance immunosensor; gliadin; Analysis method; Biosensor; Crystals; Gliadin; Plant protein; Control method; Detection; Immunosensor; Food; Quartz microbalance
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf2047866

This work develops a label-free gliadin immunosensor that is based on changes in the frequency of a quartz crystal microbalance (QCM) chip. A higher sensitivity was obtained by applying 25 nm gold nanoparticles (AuNPs) to the surface of a bare QCM electrode. Subsequently, chicken anti-gliadin antibodies (IgY) were immobilized directly on the AuNP-modified surface by cross-linking amine groups in IgY with glutaraldehyde. Experimental results revealed that the change in frequency exhibited when 2 ppm gliadin was bound to the AuNP-modified electrode was 35 Hz (48%) greater than that of the bare gold electrode. The linear dynamic range in 60% ethanol was from 1 × 101 to 2 × 105 ppb gliadin, and the calculated limit of detection (LOD) was 8 ppb. The entire detection process was completed in 40 min and was highly repeatable. Additionally, the AuNP-modified QCM system generated results in the detection of gliadin in 10 commercial food products that were consistent with those obtained using an AOAC-approved gliadin kit. In conclusion, the QCM platform provides a potential alternative means of ensuring that people with wheat allergies and celiac patients have access to gliadin-free food.