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.