A highly sensitive glucose biosensor based on a micro disk array electrode design modified with carbon quantum dots and gold nanoparticles

• Published in: Electrochimica acta 2019-03, Vol.298, p.97-105
• Main Authors: Buk, Vuslat, Pemble, Martyn E.
• Format: Article
• Language: English
• Subjects: Arrays; Atomic force microscopy; Biosensors; Carbon; Carbon quantum dots; Design modifications; Electrodes; Glucose microbiosensor; Glucose oxidase; Gold; Gold nanoparticles; Micro disk array electrodes; Microelectrodes; Microfabrication; Microscopy; Nanoparticles; Quantum dots; Reproducibility; Scanning electron microscopy; Silicon substrates
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2018.12.068

A miniaturised biosensor for glucose was prepared by immobilizing glucose oxidase (GOx) onto a carbon quantum dots (CQDs)-gold nanoparticles (AuNPs) nanohybrid material which was in turn attached to gold micro disk array electrodes. The gold micro disk array electrodes (GDAE) were microfabricated on Si substrate using electronics-standard lithography, deposition and etching techniques. Each microelectrode consisted of 85 gold disk electrodes with 20 μm diameter and 200 μm inter-electrode distance and were located hexagonally. The electrodes were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM) and cyclic voltammetry (CV). CV of the bare electrodes showed a symmetrical sigmoidal voltammogram arising from their radial diffusion profile. The electrodes developed were used to fabricate a miniaturised glucose biosensor. The resulting biosensor exhibited a high sensitivity of 626.06 μA mM−1 cm−2 towards glucose detection with excellent reproducibility and reusability. The superior performance of the biosensor is discussed in relation to the use of the micron-sized low density disk array electrodes. Note that the sizes of the components shown are not drawn to scale. [Display omitted] •Wafer scale fabrication of the micro disk array electrodes is shown to be facile.•A micro disk array biosensor based on CQDs/AuNPs-GOx nano-bio-hybrid material has been successfully developed.•The biosensor exhibited a superior sensitivity of 626.06 μA mM−1 cm−2 towards glucose.