Keychain Detector Could Catch Food Allergens Before It’s Too Late

For kids and adults with food allergies, a restaurant outing can be an anxiety inducing experience. Even when care is taken, freshly prepared or packaged meals can accidentally become cross-contaminated with an offending food that triggers a reaction. Now researchers report in the journal ACS Nano the development of a new portable allergen-detection system — including a keychain analyzer — that could help prevent trips to the emergency room.

Most people with food allergies manage their condition by avoiding the specific nuts, fish, eggs, or other products that cause a reaction. Reactions can range  from a mild rash to life-threatening anaphylaxis, a severe reaction that shocks your immune system, causes a sudden drop in your blood pressure, narrows your airways, and blocks your breathing. It’s not always possible to avoid an allergic reaction because food can be mislabeled or cross-contaminated. Conventional methods to detect these hidden triggers either require bulky laboratory equipment, or they are slow and don’t pick up on low concentrations. Ralph Weissleder, Hakho Lee, and colleagues wanted to make a more practical, consumer-friendly option.

The researchers developed a $40 portable allergen-detection system called Integrated Exogenous Antigen Ttesting, or iEAT. It consists of a handheld device to extract allergens from food via immunomagnetic enrichment and an electronic keychain reader for sensing allergens that wirelessly communicates the results to a smartphone.

Keychain detector could catch food allergens before it’s too late
A portable allergen-detection system with a keychain analyzer could help people with food allergies test their meals.
American Chemical Society

The allergens are extracted with magnetic beads and labeled with antibodies containing an oxidizing enzyme. When these magnetic beads are mixed with electron mediators (molecules used to move electrons) and placed on the electrode, the oxidizing agent on the allergen reduces the electron mediators and produces a quantifiable electric current.

In less than 10 minutes, the prototype could detect five allergens, one each from wheat, peanuts, hazelnuts, milk, and egg whites at levels even lower than the gold standard laboratory assay. Testing on samples of menu items from restaurants showed some allergens in unexpected dishes and beverages. For example, it found gluten in salad and an egg protein in beer. Although the prototype was designed to sense five allergens, the researchers say the device could be expanded to test for additional compounds, including other allergens and non-food contaminants such as pesticides.

The authors acknowledge funding from the National Institutes of Health and Taiwan’s Ministry of Science and Technology Postdoctoral Research Abroad Program.

Read more about the research: “Integrated Magneto-Chemical Sensor For On-Site Food Allergen Detection,” ACS Nano, 2017, Article ASAP.