Wearable Microneedle Patch for Transdermal Electrochemical Monitoring of Urea in Interstitial Fluid

Abstract

Microneedle-based wearable electrochemical biosensors are the new frontier in personalized health monitoring and disease diagnostic devices that provide an alternative tool to traditional blood-based invasive techniques. Advancements in micro-and nanofabrication technologies enabled the fabrication of microneedles using different biomaterials and morphological features with the aim of overcoming existing challenges and enhancing sensing performance. In this work, we report a microneedle array featuring conductive recessed microcavities for monitoring urea levels in the interstitial fluid of the skin. Microcavities are small pockets on the tip of each microneedle that can accommodate the sensing layer, provide protection from delamination during skin insertion or removal, and position the sensing layer in a deep layer of the skin to reach the interstitial fluid. The wearable urea patch has shown to be highly sensitive and selective in monitoring urea, with a sensitivity of 2.5 mV mM −1 and a linear range of 3 to 18 mM making it suitable for monitoring urea levels in healthy individuals and patients. Our ex vivo experiments have shown that recessed microcavities can protect the sensing layer from delamination during skin insertion and monitor changing urea levels in interstitial fluid. This biocompatible platform provides alternative solutions to the critical issue of maintaining the performance of the biosensor upon skin insertion and holds great potential for advancing transdermal sensor technology.

Unlocking the Potential of Wearable Sensors in Healthcare and Beyond

“…The device operates with a miniaturized electrochemical analyzer equipped with wireless connectivity to a mobile electronic device for capturing, processing, and displaying the data with potential applicability in management of diabetic ketoacidosis and personal nutrition and wellness . In another recent study, Voelcker and colleagues illustrate a microneedle array for the enzyme-mediated detection of urea in the interstitial fluid of the skin, as a biomarker of renal malfunction . This microneedle array features conductive recessed microcavities, with electropolymerized polyaniline boronic acid that served as an enzyme immobilization and detection layer for ammonia produced in a reaction with the urease enzyme; a Nafion membrane coating is used to protect it from the potential leaching of the urease enzyme.…”

A Celebration of Meetings Large and Small: A Dispatch from the 2024 Porous Semiconductors Science and Technology International Conference

“…This year the Leigh T. Canham Award in Porous Semiconductors Science and Technology went to Nicolas H. Voelcker, Professor at Monash Institute of Pharmaceutical Sciences and Director of the Melbourne Centre for Nanofabrication in Australia. Nico is a leader in the application of nanoporous materials to a wide range of sensor problems, deploying electrochemical , and microneedle , technologies, in particular. The award appropriately recognized his many innovative and exciting contributions to this field.…”