Self-Supporting Flexible Enzyme-Free Sensor Based on CoS-PPy-CP for Glucose Detection

Portability and intelligence are the future development trend of sensor electrodes. As a common flexible self-supporting material, carbon paper is often used as a base material for sensing electrodes due to its advantages such as easy miniaturization, good electrical conductivity and large surface area. Modification of functionalized nanomaterials on carbon paper can greatly increase its application potential and expand the application range of sensing electrodes. In this work, electro-deposition technology is used to deposit PPy on the surface of flexible carbon paper, and then CoS nanospheres are grown by hydrothermal method. Among them, CoS shows excellent catalytic performance for glucose, while PPy can provide excellent electrical conductivity and a larger CoS growth surface. The current change will be produced by the conversion of Co2+ and Co3+ in the process of CoS catalyzing glucose, and the glucose concentration can be indirectly detected by monitoring the electrode current change. Under optimized conditions, the proposed sensor owns significant glucose oxidation activity in range of 0.5 μM to 465.5 μM and 565.5 μM to 8415.5 μM, and the LOD is estimated to 0.14 μM(S/N = 3). Besides, its application and standard addition test results are consistent with those of commercial blood glucose meters. This study shows that CoS-PPy-CP is a unique and promising material that can be applied to glucose detection in practice.