Reusable gallium-based electrochemical sensor for efficient glucose detection

Among wearable sensing devices, electrochemical sensors are overwhelming in biochemical detection due to their simple design but high sensitivity. Most electrochemical sensors are disposable, which significantly impairs the service life. Here we present a reusable gallium (Ga)-based multilayer electrochemical glucose biosensor to extend noninvasive monitoring of glucose in the interstitial fluid. This multilayer sensor includes Ga as a conductive interconnector, poly(3,4-ethylenedioxythiophene) as an electrode layer to prevent oxidation and metal leakage, a nano-Pt layer to enhance the electrochemical properties, and a nano-Prussian blue layer for reducing the hydrogen peroxide reduction potential. The biosensor can be renewed without causing damage to its overall structure by automatically eliminating the modified nanocomposites via the electrolysis-induced bubbles. The biosensor showed high sensitivity (24.6 μA mM^-1 cm^-2), wide linear range (0.01-26 mM), excellent stability (i.e., pH, long-term use) and superior selectivity, that is comparable to those of the current electrochemical tools for glucose detection. More importantly, incorporated with the reverse iontophoresis, the Ga-based hybrid sensor was applied as a skin patch on rat for the in vivo noninvasive and continuous monitoring of interstitial fluid glucose. The results showed a good correlation with that measured by blood glucometer. As a whole, this Ga-based electrochemical biosensor should endow new functions like biochemical analysis in biofluids for Ga-based bioelectronic sensing devices, in which almost are physical sensors. We believe that the reusability of electrochemically controllable processes may further inspire the development of more integrated and long-term stable Ga-based biosensing devices.