Anaphylaxis is not something to be messed around with, as it’s an allergic reaction that can prove fatal if not halted. That’s where an experimental new skin patch comes in, as it could warn of the onset of anaphylaxis while there’s still plenty of time to head it off.
Usually taking the form of extreme swelling and tightening of the airways, anaphylaxis typically manifests within two hours of exposure to certain proteins in foods such as eggs, nuts, milk, and seafood. These foods themselves may be easy enough to avoid, but they can sometimes unknowingly be present as ingredients in prepared dishes.
And although the proteins cause no problems for most people, in allergic individuals they trigger the production of antibodies known as immunoglobulin E (IgE). Those antibodies in turn facilitate the release of histamine, tryptase and other biomolecules, resulting in a severe allergic response.
It is possible to detect elevated IgE levels in the bloodstream via blood tests soon after exposure, thus providing an early warning that an anaphylaxis attack will occur unless preventive measures are taken. The problem is … well, that a painful, invasive blood sampling is involved.
The new AllergE patch, on the other hand, would painlessly and continuously provide IgE readings via the skin throughout at-risk periods, such as during and after meals.
Currently being developed by scientists at Saudi Arabia’s King Abdullah University of Science and Technology (KAUST), the device features an array of tiny, porous, hollow microneedles on its underside. Each one is less than a millimeter long, and approximately the width of a human hair.
When the patch is pressed against the user’s skin, the polymer needles only pierce the very top layer of the skin, not reaching the underlying nerve endings. They do, however, reach the interstitial fluid between the skin cells. IgE levels in that fluid correspond to those in the bloodstream.
As the IgE antibodies are carried by the fluid into the microneedles, they encounter DNA strands known as aptamers contained within. Upon contact with the antibodies, those aptamers twist into new shapes, generating an electrochemical signal in the process.
An electrode and other electronics, which are integrated into the patch, translate that signal into a quantitive reading of IgE levels. In tests performed so far on artificial and excised human skin, the device was able to detect IgE concentrations as low as 30 picograms per milliliter, which is reportedly “hundreds of times more sensitive” than most current methods.
Once the technology is developed further, it is hoped that the patch could wirelessly relay its readings to an app on the user’s smartphone.
A paper on the research, which was led by Asst. Prof. Dana Alsulaiman and Prof. Khaled Salama, was recently published in the journal ACS Materials Letters.
Source: KAUST
