The prevalence of food allergy has been increasing in recent decades, at least in western countries like the UK and US1. Allergic reactions to food are responsible for approximately 200,000 emergency room visits each year2. Protein antigens are usually responsible e.g.
Ara h1 (peanut), gliadin (wheat), casein (milk). A biosensor capable of detecting these allergens in real time would be highly desirable.The biosensor would consist of multiple parts: a sampling kit, a microcontroller device, and an app. The sampling kit would include a small, disposable tube containing a protein extraction buffer, and beads covered in antibodies complementary to the protein antigen of interest. The antigens would then be labelled with a secondary antibody conjugated to an oxidising enzyme like horseradish peroxidase (HRP).
A chromogenic substrate, like tetramethylbenzidine (TMB), would then be added. These reagents could be added in various ways e.g. poured in from a separate compartment in the tube lid.
HRP would catalyse the oxidation of TMB and the reduction of hydrogen peroxide.The microcontroller device, that should be small enough to be worn on a necklace or keychain, will have extendable electrodes. The microcontroller docks onto the sampling tube and the electrodes submerge in the solution. The oxidised TMB would then be reduced by accepting electrons from an electrode. This would generate an electrical current, which is measured by another electrode. The microcontroller would measure the electrical current from the working to counter electrodes, whilst maintaining a constant potential between the working and reference electrodes. The current levels are converted to allergen concentrations according to preloaded standard tables.
The microcontroller would then transmit the results via Bluetooth to the user’s smartphone, where they can be visualised and tracked on the app.This biosensor would be attractive not only to those suffering from food allergies, but also to the increasing number of people that are avoiding allergens like gluten for reasons other than hypersensitivity. The product could even be desirable to consumers without allergies or dietary preferences, that may want to use the biosensor in conjunction with the app, to share the analyte statistics of their food along with their photos to social media platforms.