Epigallocatechin gallate decorated carbon nanotube chemiresistors for ultrasensitive glucose detection

•Electronic detection of glucose using highly aligned CNT chemiresistors.•Reaction between EGCG and H2O2 forms the basis of sensing.•EGCG-CNT capable of detecting glucose in low concentrations (10 nM to 1 μM).•Results bode well for bloodless glucose detection.

The concentration of glucose in biological fluids is in the micromolar range, the detection of which requires devices with high sensitivity and low limit of detection (LOD). Here, we report the real-time electronic detection of glucose using an antioxidant found in green tea, namely, epigallocatechin gallate (EGCG), decorated on carbon nanotubes (CNTs) and tested in a chemiresistor configuration. The detection principle relies on the spontaneous reaction of EGCG with hydrogen peroxide, a reactive oxygen species released during glucose oxidation, which is translated electrically as a change in CNT conductance. Our results suggest that the response of EGCG decorated CNTs was far superior to that of the bare CNT based device. The sensor detected glucose ranging from 10 nM to 1 μM with LOD of ∼8.7 nM, which is much lower than the commercially available finger-pricking based glucose sensors. This could pave the way for developing simple resistivity-based sensors capable of glucose detection in biological fluids other than blood, such as sweat and saliva.

Graphical abstractWe report the detection of glucose at very low concentrations by using aligned CNTs coated with EGCG in a chemiresistor configuration. The low limit of detection and high selectivity towards glucose bodes well for blood-less glucose detection.Figure optionsDownload full-size imageDownload as PowerPoint slide