Wearable Stretchable Microneedle-Based Patch for Online Detection of Multiple Biomarkers in Interstitial Fluids

With the increasing number of aging populations, the outbreak of new infections and diseases, and the stressed lifestyle, the need for sophisticated advanced technologies for online health monitoring is increasing. In this regard, measuring and evaluating health related biomarkers and physiological indexes have a considerable advantage and is considered an informative prognostic tool for health assessment. However, these biomarkers are usually measured and analysed using bulky laborious equipment, painful and time-consuming methods which require expert personnel to perform, may cause irritations and infections and are usually collected and analysed offline and not continuously. Using wearable biosensors for online biomarkers monitoring can be a promising approach to overcome this condition. In this regard, biosensors based on field-effect transistors (FETs) have promising advantages, including high sensitivity, quick response, and easy fabrication. Most of the currently developed FET designs are used only for sensing sweat and in-vitro blood/interstitial fluids (ISF). Using ISF for online detection of biomarkers and long-term health monitoring with FETs has not yet been fully resolved. In this work, we developed an innovative stretchable, flexible, skin-conformal and quick-response microneedle-based extended gate FET (MN-EGFET) biosensor patch for online and real-time detection of multiple biomarkers including glucose, sodium, cortisol, and pH in the ISF for minimally invasive health monitoring along with high sensitivity, low limit of detection, excellent biocompatibility, and on-body mechanical stability. On-body measurements were also carried out on a healthy individual to evaluate the long-term health monitoring performance of our wearable microneedle device against a gold standard commercial device. Both devices were found to show a similar performance and tendency, indicating the great promise for our device in clinical and on-body applications. This wearable microneedle device was also integrated with a flexible wireless data transmission chip including Internet-of-Things (IoT) cloud, to transmit the data continuously to a smartphone, demonstrating its effectiveness as a diagnostic and monitoring tool in primary and specialized healthcare, as well as its potential in real-life home healthcare and clinical applications.