Feb 9 2018
The number of food options in stores is growing for people suffering from celiac disease and gluten sensitivities. However, as per the current tests for gluten, all of the substances are not found in foods, and as a result, some products are labeled as “gluten-free” when they are not.
Now, researchers have created a fast gluten detector that can detect and measure various sources of gluten than those available on the market today. The study has been reported in ACS Sensors.
Gluten is a range of proteins present in plants such as oats, barley, and wheat. The enzyme-linked immunosorbent assay, also known as ELISA, is the de facto standard for detecting the levels of these proteins in foods. However, this test has several disadvantages – it is not reliable, differs by manufacturer, and can give false negatives, which can lead to health problems for people who are sensitive to proteins. Further, a different ELISA test is needed to optimally detect each type of gluten — oat, barley, or wheat — because some individuals can be sensitive to proteins from one source but not to proteins from another source. Due to these limitations, researchers have been looking for alternative techniques, for example, mass spectrometry and DNA-based sensors to perform this testing. However, DNA-based sensors cannot reflect the gluten content accurately, while mass spectrometry is costly and needs technical expertise despite being sensitive and accurate.
Hence, Scott P. White, Kevin D. Dorfman, and C. Daniel Frisbie wanted to develop a more comprehensive detector. They subsequently designed an immunological assay based on floating gate transistors. The team performed the test on a device that features tiny microchannels which allow a sample to move through. If gluten is present in a specimen, the substance can latch to one of three capture agents, which can be either a DNA-based aptamer or antibodies, that individually bind to gluten proteins from specific sources. This binding induces a shift in the voltage read-out of the transistor and can give a chemical fingerprint that indicates whether the gluten was from wheat or barley, for instance.
In comparison to the ELISA test, the newly developed sensor generated results 45 minutes faster owing to automated sampling and fewer processing steps. As with the ELISA test, the detectors could perceive less than 20 parts per million of gluten – the stipulated maximum limit by the U.S. Food and Drug Administration for a “gluten-free” designation.
The National Science Foundation, the Office of Naval Research, and the University of Minnesota funded the study.