Bionics-inspired strong coupling of streptococcus-like NiCo₂O₄ to needle-like MnO₂ for enhanced electrocatalytic determination of glucose

Duozhe Chen^a,1, Shuang Wang^a,1, Maoxiang Liu^a, Juanjuan Gao^a, Haiou Song^b,*, Shupeng Zhang^a,*

¹ D.Z. Chen and S. Wang contributed equally to this work.

Abstract

Bionics-inspired streptococcus-like NiCo₂O₄ coated needle-like MnO₂ architecture has been synthesized successfully, denoted as NiCo₂O₄-MnO₂, and the nonenzymatic electrochemical sensor based on NiCo₂O₄-MnO₂ exhibits highly sensitive determination towards glucose. MnO₂ nanowires are regarded as effective nucleation sites, which allows uniformly growing of NiCo₂O₄ as electrocatalytic centers on its surface by a hydrothermal method. The rational combination of streptococcus-like NiCo₂O₄ and needle-like MnO₂ can effectively prevent the aggregation of nanomaterials due to the formation of 3D network, promote the electron transportation, and provide more electrocatalytic sites. The attractive nanostructure and composition were better confirmed by scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy, etc. The strong coupling of NiCo₂O₄-MnO₂ inspires the synergistic effect, showing a low detection limit of 0.036 μM (S/N = 3) for glucose in 0.1 M NaOH, a high sensitivity of 2887.57 μAmM⁻¹cm⁻² and a wide response range (from 1 to 7100 μM). Moreover, the novel sensor exhibited high stability and good reproducibility. The sensor was highly selective to glucose in the presence of commonly interfering species like dopamine, uric acid, ascorbic acid, sodium chloride, fructose, galactose and mannose, and successfully applied to sensing glucose concentration in human serum samples.