Highly sensitive non-enzymatic wireless glucose sensor based on Ni–Co oxide nanoneedle-anchored polymer dots

Abstract

Polymer dot (PD)-bridged nickel cobalt oxide (NiCo2O4 (NCO)) nanoneedle-assembled globe-shaped clusters for high-performance glucose sensors were prepared via the consecutive calcination and packaging of PDs using the hydrothermal technique. The sp2-conjugated bridge of electrons, abundantly available catechol functionalized active sites offered by the PDs, and porous structure of NCO created effective electron transport routes for electrocatalytic reactions. The remarkable synergy between the conductive PDs and NCO conferred the PDs-bridged NCO (PDs-NCO) exceptional electrocatalytic activity for glucose detection. Under the optimal applied potential of +0.5 V, the developed PDs-NCO-coated Ni foam (NF) electrode presented the broad detection range from 5 μM to 0.25 mM, sensitivity of 806.17 μA mM−1 cm−2, detection limit of 2.75 μM, and exceptional selectivity. Furthermore, the PDs-NCO-coated NF electrode achieved the specific capacitance of 35.63 F g−1 at the current density of 0.5 A g−1 and superb cycling stability including the 96.7% specific capacitance retention over 5000 charge-discharge cycles. In addition, glucose-sensing could be easily monitored using a wireless sensor on a smartphone. The combination of NCO and PDs represents an innovative approach for constructing high-performance, reusable, non-enzymatic glucose sensors with low detection limit, high sensitivity, and excellent selectivity.