Search

Thanks to rapid technological innovation over the last decade, a wide range of wearable devices have emerged, playing an inspiring role in healthcare, diagnostics, and sports monitoring. This review summarizes recent progress in the development and application of electrochemical (EC) sweat sensors and self-powered systems for wearable applications. Presented here are the most common types of EC sweat sensors, namely potentiometric ion-selective electrodes, amperometric enzymatic and non-enzymatic sensors, as well as differential pulse voltammetric sensors. The sensing principle and novel functional nanomaterials that are used to enhance the performance of wearable sweat sensors and their applications are summarized. The recent advancement of battery-free wearable devices is presented, including self-powered biofuel cells (BFC), energy harvesting from novel materials and its strategy, are also discussed. The challenges in, and opportunities for, the development of sweat sensor-based wearable systems moving forward are reviewed, with the aim of shedding some light on future directions. IEEE

For the first time, an improved wearable electrochemical sensor is proposed for monitoring ammonium content in sweat using a specific ionophore as the ion selective membrane (ISM) on a 3D porous structure comprising of Metal- organic framework/graphene (MOF/graphene) network. The sensor exhibits an almost ideal Nernstian slope of 59.23±1.52 mV/log [NH4+] (4.72 % RSD, N=4). The sensor also presents an extremely low charge transfer resistance (Rct). Furthermore, the hydrophobic property of the porous MOF/graphene layer promotes an excellent reversible sensing response to a wide range of NH4+ concentrations by inhibiting aqueous layer generation between the ISM and the screen-printed carbon electrodes (SPC) interface. Screen-printing technology allows the sensor to be fabricated at a low cost with enhanced flexibility in component design and integration. © 2019 IEEE.

A wide type T4 Phage-based Impedimetric Micro-Electrochemical Sensor (T4PI-MES) was proposed for sensitive and specific detection of bacteria. The sensor surface was chemically functionalized with SAM and EDC/NHS to immobilize T4 phage, and the electrochemical impedance spectroscopy (EIS) was applied to detect different bacteria concentration and viability. The successful functionalization of the sensor was confirmed by Fourier Transform Infrared Spectroscopy (FTIR), and the results of EIS showed that T4PI-MES could provide a wide dynamic range (102~108 cfu/mL) and low LOD (102 cfu/mL) for Escherichia coli (E. coli) detection. © 17CBMS-0001.

Wearable electrochemical sensors have attracted tremendous attention and are experiencing rapid growth in recent years. Sweat, which contains abundant clinically relevant biomarkers, is one of the most suitable biological fluid to be monitored continuously. We propose a novel wearable and stretchable electrochemical sensors (WSES) on a flexible substrate to detect ammonium in sweat using 3D reduced Graphene Oxide-Carbon Nanotube (rGO-CNT). The fabricated WSES shows excellent output stability, stretchability, and biocompatibility. © 17CBMS-0001.

Wearable electrochemical sensors have attracted tremendous attention and are experiencing rapid growth in recent years. Sweat, which contains abundant clinically relevant biomarkers, is one of the most suitable biological fluid to be monitored continuously. We propose a novel wearable and stretchable electrochemical sensors (WSES) on a flexible substrate to detect ammonium in sweat using 3D reduced Graphene Oxide-Carbon Nanotube (rGO-CNT). The fabricated WSES shows excellent output stability, stretchability, and biocompatibility. © 17CBMS-0001.

Dimensional analysis was applied to systematically study the diffusion-limited (DL) and chargetransfer reaction-limited (CRL) processes in Micro electrochemical sensors (MECSs). The electrochemical impedance spectroscopy (EIS) for MECS to detect hydrogen and ammonium ions was fitted with the equivalent circuit model (ECM). With the help of Buckingham Pi Theorem, two dimensionless parameters: normalized impedance and reaction-diffusion-frequency were identified to distinguish these two processes. The results showed that these two parameters can be applied not only in our fabricated MECSs for detecting hydrogen and ammonium ions, but also in other reported relevant works for detecting copper ions and DNA molecules.