Skin patch measures patients' antibiotic levels in real time
When someone is being treated for a serious infection, it's important to know the level of antibiotics that are presently in their bloodstream. Although this is currently ascertained via blood samples, it could soon be better-managed using a microneedle skin patch.
Developed by scientists at Britain's Imperial College London, the prototype device features an array of tiny enzyme-coated electrode needles on its underside.
When the sensor patch is pressed against a patient's skin, those needles painlessly penetrate the outermost layer of that skin. If the targeted antibiotic is present in the interstitial fluid between the skin cells (reflecting levels in the bloodstream), the enzyme on the needles will react with it, causing the fluid's pH level to change.
The needles detect that alteration. When the patch is connected to an external monitor, it is thus able to display the concentration of antibiotics in the patient's bloodstream, based on the extent of the pH-change.
In lab tests, small microneedle patches were placed on the forearms of 10 healthy volunteers, where they were able to accurately measure fluctuating levels of orally-administered penicillin. Their readings matched those of blood samples taken at the same times.
Down the road, it is hoped that the sensing technology could be integrated into wearable devices that automatically inject more antibiotics into patients as levels in their bloodstream drop below a given level.
"When patients in hospital are treated for severe bacterial infections, the only way we have of seeing whether antibiotics we give them are working is to wait and see how they respond, and to take frequent blood samples to analyze levels of the drugs in their system – but this can take time," says lead scientist Dr. Timothy Rawson. "Our biosensors could help to change that. By using a simple patch on the skin of the arm, or potentially at the site of infection, it could tell us how much of a drug is being used by the body and provide us with vital medical information, in real time."
A paper on the research was recently published in the journal The Lancet Digital Health. And as a side note, a team from the University of British Columbia and the Paul Scherrer Institute have previously developed a skin patch that measures medication levels in the bloodstream, although it does so via micro-optical fibers.
Source: Imperial College London