Capillary-driven microchip integrated with nickel phosphide hybrid-modified electrode for the electrochemical detection of glucose.

Background: Transition metal phosphides with properties similar to platinum metal have received increasing attention for the non-enzymatic detection of glucose. However, the requirement of highly corrosive reagent during sample pretreatment would impose a potential risk to the human body, limiting their practical applications.

Results: In this study, we report a self-powered microfluidic device for the non-enzymatic detection of glucose using nickel phosphide (NiP) hybrid as the catalyst. The NiP hybrid is synthesized by pyrolysis of metal-organic framework (MOF)-based precursor and in-situ phosphating process, showing two linear detection ranges (1 μM-1 mM, 1 mM-6 mM) toward glucose with the detection limit of 0.32 μM. The good performance of NiP hybrid for glucose is attributed to the synergistic effect of NiP active sites and N-doped porous carbon matrix. The microchip is integrated with a NaOH-loaded paper pad and a capillary-based micropump, enabling the automatic NaOH redissolution and delivery of sample solution into the detection chamber. Under the optimized condition, the NiP hybrid-based microchip realized the detection of glucose in a user-friendly way. Besides, the feasibility of using this microchip for glucose detection in real serum samples has also been validated.

Significance: This article presents a facile fabrication method utilizing a MOF template to synthesize a NiP hybrid catalyst. By leveraging the synergy between the NiP active sites and the N-doped carbon matrix, an exceptional electrochemical detection performance for glucose has been achieved. Additionally, a self-powered chip device has been developed for convenient glucose detection based on the pre-established high pH environment on the chip.