New device that fits on a key chain can accurately test for allergens

Oct 26 2017

More than 50 million Americans have food allergies and often just trace amounts of allergens can trigger life-threatening reactions. Now, researchers at Harvard Medical School, funded by the National Institute of Biomedical Imaging and Bioengineering, have developed a $40 device that fits on a key chain and can accurately test for allergens, like gluten or nuts, in a restaurant meal in less than 10 minutes.

Food allergies are extremely common. Those fortunate enough not to be affected are likely to have a friend or family member who struggles to avoid dangerous reactions to food allergens every day. In the US, Federal regulations require packaged foods to disclose the presence of some of the most common allergens such as gluten, nuts, and milk products, which is helpful, but not always accurate.

When it comes to eating out, people with allergies have had to rely on their knowledge of what ingredients contain the allergens they must avoid, and on the efforts of the restaurant to provide dishes that eliminate allergens; and they must work to avoid cross-contamination between different ingredients in the kitchen. All in all, this approach generally leaves those with allergies with little choice but to completely avoid any foods that have the chance of containing an allergen, either in the natural ingredients, or because of contact with other foods containing allergens during preparation in a restaurant kitchen.

Recognizing this widespread public health problem, researchers at Harvard Medical School in Boston have developed a system called integrated exogenous antigen testing (iEAT). The purpose of the iEAT system is to give those who suffer from food allergies a rapid, accurate device that allows them to personally test foods in less than 10 minutes.

Development of the iEAT system was led by co-senior team leaders Ralph Weissleder, M.D., Ph.D., the Thrall Professor of Radiology, Professor of Systems Biology at Harvard, and Director of the Center for Systems Biology (CSB) at Massachusetts General Hospital (MGH); and Hakho Lee, Ph.D., Associate Professor in Radiology at Harvard, Hostetter MGH Research Scholar, and Director of the Biomedical Engineering Program at the CSB, MGH. The work, is published in the August 2017 issue of ACS Nano.

"This invention is a fortuitous combination of the interests and expertise of Drs. Weissleder and Lee in developing tools for early disease detection, magnetic sensors, and point-of-care diagnostics," said Shumin Wang, Ph.D., director of the NIBIB program in Biomagnetic and Bioelectric Devices. "They have taken technologies they developed for other medical problems, such as early cancer detection from blood samples, and applied them to solving the daily, potentially life-threatening difficulties of people with food allergies-;a highly significant highly significant public health problem that incurs 25 billion dollars in annual costs in the U.S. alone."

The device consists of three components. A small plastic test tube is used to dissolve a small sample of the food being tested and to add the magnetic beads that capture the food allergen of interest, such as gluten. A bit of that solution is then dropped onto electrode strips on a small module that is then inserted into the electronic keychain reader. The keychain reader has a small display that indicates whether the allergen is present, and if so, in what concentration. Testing showed that measurements of the concentration of the allergen is extremely accurate.

The high level of accuracy is very important. For example, even though Federal standards say that a food is considered gluten free if it has a concentration of less than 20 mg per kg of gluten, everyone's sensitivity is different, and many people would have a reaction at much lower gluten concentrations. Extensive testing of iEAT revealed that the system could detect levels of gluten that were 200 times lower than the Federal standard.

"High accuracy built into a compact system were the key goals of the project," says Weissleder. "Users can be confident that even if they are sensitive to very low levels, iEAT will be able to give them exact concentrations. Armed with accurate concentration levels they will not have to completely avoid potentially problematic foods, but will know whether an allergen is at a dangerous level for them or a concentration that is safe for them to eat."

Beyond obtaining the information they need in about 10 minutes using iEAT, a novel addition to the system was the development of a cell phone app, which offers the possibility of addressing food allergies at the community level. Using the app, users can compile and store the data they collect as they test different foods for various allergens at different restaurants and even in packaged foods. The app is set up to share this information online with both time and location stamps indicating when, where, and in what food or dish an allergen reading was taken. With the app, people will eventually have a personal record of levels that trigger a reaction. Others with the app will be able to find restaurants with foods they like to eat that consistently have no or low levels that are below the individual's triggering concentration.

"Although we believed iEAT could address a significant public health problem, we were surprised at the amount of interest the device has generated. We are receiving calls from people asking if we can adapt iEAT to test for other substances such as MSG or even pesticides," said Hakho Lee, co-senior leader of the project. "The good news is that we definitely can adapt the device to test for just about any allergen or substance."

Towards that end, the research team has granted a license to a local start-up company to make iEAT commercially available. The company plans to merge the three components into a single module to make it even easier and more convenient to use. Production on a larger scale is also expected to reduce the price of the unit considerably.

In addition to contributing to food safety at the individual and community levels in the U.S., the inventors point out that the device would be very valuable for travelers in countries where there are no specific requirements for food labels. Another use of the system would be to trace the source of food contamination with bacteria such as E. Coli or Salmonella to a specific food-processing site by testing DNA in the samples to potentially identify and contain an outbreak more quickly.

Source: https://www.nibib.nih.gov/news-events/newsroom/food-allergy-lab-fits-your-keychain