Wearable On-Skin Chemo-Sensors

In an increasingly health-aware population and a move towards remote diagnostics, remote healthcare monitoring and cloud-based med-tech, we tap on the ubiquitous and unlimited reservoir of on-skin biomarkers, including sweat metabolites, in developing a wearable, non-invasive, continuous and real-time sensor – a printed, multiplexed biosensor. Such a device can be colorimetric or electrochemical in its sensing mechanism. Our integrated devices are designed and developed with scalability and translation in mind – ensuring printability (for scalable manufacturing), ease of fabrication routes, and solid-state and miniaturised prototype.[1-8]<br/><br/>In particular, firstly, we introduce a newly-published fully-printed paper-based patch, printed from our development of a ceramic-based ink along with nanoparticle-functionalisation, for multi-metabolite and sweat rate monitoring.[1]<br/><br/>Next, we highlight the importance of enzymes in such enzymes-based biosensors (enzymatic reactions to detect target analytes), where their intrinsic instability poses a bottleneck in practical long-term use. Previous methods at enhancing enzyme stability had always been met with a trade-off in sensitivity, selectivity or performance/efficacy. Herein, we showcase a novel materials-based approach, a one-pot synthesis of co-encapsulating enzymes and carbon-dots in a metal-organic framework, overcoming the aforementioned compromise. We achieve an electrochemical highly-stable and highly-sensitive device, and demonstrate it as a touch-based sweat sensor. [2]<br/><br/>Lastly, we briefly highlight an even more holistic approach in developing a printable, non-invasive, real-time and continuous electrochemical sensor for sweat-based and ‘dry-skin’ based on-skin chemosensing. [3-7]<br/><br/><br/>[1] XT Zheng, WP Goh, Y Yu, L Sutarlie, DY Chen, SCL Tan, C Jiang, M Zhao, T Ba, H Li, X Su, L Yang. Skin Attachable Ink Dispenser Printed Paper Fluidic Sensor Patch for Colorimetric Sweat Analysis. <i>Advanced Healthcare Materials</i>, 2302173 (<b>2023</b>). <i>Online <b>28 Oct 2023</b>.</i><br/>[2] XT Zheng, MWN Leoi, Y Yu, SCL Tan, N Nadzri, WP Goh, C Jiang, XP Ni, P Wang, M Zhao, L Yang. Co-encapsulating Enzymes and Carbon Dots in Metal–Organic Frameworks for Highly Stable and Sensitive Touch Based Sweat Sensors. <i>Advanced Functional Materials</i>, 2310121 (<b>2023</b>). <i>Online <b>30 Nov 2023.</b></i><br/>[3] A graphite-based paste/ink for electrochemical sensors, WP Goh, CY Jiang, Y Yu, XT Zheng, YX Liu, LYang, PCT/SG2022/050407, Singapore (<i>PCT filed</i>), 2022.<br/>[4] A kirigami paper fluidic channel for sweat sensors, CY Jiang, WP Goh, XT Zheng, Y Yu, YX Liu, L Yang,SG-10202113328Q, Singapore (<i>PCT filed</i>), 2023.<br/>[5] Y Yu, L Yang et al, Materials Today Advances, 14, 100238 (2022).<br/>[6] Stretchable biochemical interface for solid epidermal analytes, YX Liu, WP Goh, XT Zheng, Y Yu, SCL Tan,CY Jiang, RT Arwani, L Yang, SG-10202202318P, Singapore (<i>PCT filed</i>), 2023.<br/>[7] RT Arwani, WP Goh, CY Jiang, XT Zheng, Y Yu, L Yang YX Liu et al, <i>Under Revision </i>2023.