A wearable microneedle patch designed to track potent antibiotic levels in real time could soon replace traditional blood draws for critical patients, according to an interdisciplinary research team at KAUST. Published in the journal Device, the platform continuously monitors drug concentrations in the interstitial fluid beneath the skin, targeting medicines with narrow therapeutic windows like vancomycin.
Overcoming the Limits of Traditional Blood Testing
The standard method for monitoring therapeutic drugs relies on drawing blood and waiting hours for laboratory results, a process that doctoral student Yurii Tsyban describes as offering only a snapshot of a dynamic system. According to KAUST researchers, individual bodies metabolize medications differently, meaning standard doses can easily prove toxic or ineffective depending on the patient. Interstitial fluid—the liquid found in microscopic spaces between cells in the dermis—contains nutrients and metabolites whose drug concentrations closely reflect those in the bloodstream. By targeting this dermal layer, the new patch aims to provide continuous data without repeated hypodermic needle insertions.
How the Microneedle Aptamer Sensor Works
The wearable device features a tiny microneedle array that lightly punctures the outer skin layers to reach the interstitial fluid. According to Tsyban, the microneedles are coated with a DNA aptamer, which is a short DNA strand designed to selectively bind to a target drug molecule. When vancomycin is present in the fluid, the aptamer changes shape, producing a measurable electrochemical signal. A miniature mobile potentiostat designed by the team processes this signal, converts it into an estimated drug concentration, and wirelessly transmits the data to a smartphone app.
Initial laboratory tests using artificial interstitial fluid demonstrated that the sensing system remained stable for up to 10 hours. Furthermore, animal studies in mice showed that the device successfully tracked repeated dosing events over a four-hour window, revealing distinct differences in drug levels between individual subjects. Khaled Nabil Salama, who supervised the project, notes that while the initial results are promising, significant work remains before clinical use. The team must complete required biocompatibility studies and improve long-term sensor stability before the patch can be deployed in hospitals, outpatient clinics, and home settings.
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