Time is Life -
The AllerSense Patch Provides It
How It Works
AllerSense's Layered Approach
Stage One
Recognizing a Reaction
Needle Coating
First, a microneedle array electrode (MAE) patch contains an array of metal microneedle electrodes, half of which serve as a reference point. The other half are coated in the aptamer D17.4ext (45-mer, 5′Biotin GCG CGG GGC ACG TTT ATC CGT CCC TCC TAG TGG CGT GCC CCG CGC 3′) from RiNA GmbH, which is curated to attach directly to the binding sites of IgE proteins, which are activated in the event of an allergic reaction. These needles are coated with streptavidin in order to form a streptavidin-biotin linkage with the biotinylated aptamer.
Protein Binding
The streptavidin-biotin linkage is the same bond that allows the protein Extravidin-alkaline phosphatase (xAv-AP) to bind to the biotin on the needle. If IgE binding sites bind to the biotinylated aptamer, more sites on the needle are freed up for xAv-AP to the aptamer-IgE complex, allowing the dephosphorylation of p-Aminophenyl Phosphate into p-Quinonimide at this specific site near the patch, with the generation the p-Quinonimide product giving off an electrical signal.
Stage Two
Alerting the User
Potentiostat Signal Processing
An Emstat Pico Core (micro potentiostat) attached above the needles measures the difference in voltage between the reference electrodes and those coated in the biotinylated aptamer. The core then wires this information to an Analog to Digital Converter (ADC) channel in an Arduino ESP32 microprocessor that monitors the percent change in the voltage change in the voltage difference.
Buzzing to User
This change is proportional to the percent change in IgE production, which indicates whether or not an allergic reaction is taking place. Attached to the ESP32 is a piezo buzzer, and AllerSense’s algorithm instructs the microcontroller to buzz the piezo buzzer if the percent change in voltage difference exceeds a 20% increase compared to resting IgE levels, indicating the user that they are having an allergic reaction, before symptoms reveal themselves.
