High-performance non-enzymatic glucose sensing on nanocomposite electrocatalysts of nickel phthalocyanine nanorods and nitrogen doped-reduced graphene oxide nanosheets

Highly stable and efficient electrocatalytic materials are essential for developing high-performance non-enzy-matic fourth-generation glucose biosensors. In this regard, hybrid materials incorporating metal-lophthalocyanines and carbon-based nanostructures are particularly interesting. A nanocomposite of nitrogen -doped reduced graphene oxide nanosheets and nickel phthalocyanine nanorods (N-rGONs|NiPcNRs) was pre -pared. N-rGONs|NiPcNRs were highly efficient and stable electrocatalysts for non-enzymatic D-glucose electro-oxidation in alkaline media. Spectroscopic, microscopic, and electrochemical methods were used to characterize and evaluate the electrocatalytic performance of the N-rGONs|NiPcNRs. The remarkable electrocatalytic activity of N-rGONs|NiPcNRs originated from the in-situ transformation and formation of polymeric O-Ni-O oxo-bridge in alkaline electrolyte and the excellent electroconductivity of the N-rGONs. The N-rGONs|NiPcNRs with the op-timum ratio of NiPcNRs to N-rGONs presented an efficient formation of the Ni-O-Ni oxo-bridge and D-glucose electrooxidation compared to N-rGONs and NiPcNRs alone. Thus, the fabricated GCE|N-rGONs|NiPcNRs glucose sensor showed an excellent analytical performance with a high sensitivity of 1458 mu A.mM-1.cm- 2 and a detection limit of 1.43 mu M (S/N = 3) using cyclic voltammetry. For online glucose detection using chro-noamperometry, a sensitivity of 358.9 mu A.mM-1.cm- 2 with a detection limit of 5.0 mu M (the lowest concentration that could be discriminated from the buffer using GCE|N-rGONs|NiPcNRs) and a fast response time of 0.80 s was obtained. The high sensitivity of CV (1458 mu A.mM-1.cm- 2) allowed for lower limits of detection (1.34 mu M). The fabricated sensor was successfully applied for the determination of D-glucose levels in serum samples, demon-strating its potential for monitoring glucose levels in diabetes patients.

Automated summary

This study developed a highly efficient and stable electrocatalyst material, N-rGONs|NiPcNRs, and successfully applied it in a glucose biosensor, demonstrating excellent analytical performance and potential.