Enzymeless glucose sensor based on disposable Ecoflex?/graphite thermoplastic composite substrate modified with Au@GQDs

Autor(es)

Lima, Lucas F. de ; de Freitas, Amanda de S. M. ; Maciel, Cristiane Carla ; Ferreira, Andre L. ; Ferreira, Marystela ; Araujo, William R. de

• Tipo de documento: Artigo Científico
• Fonte: SENSORS AND ACTUATORS REPORTS; v. 4, p. 11-pg., 2022-11-01.

Resumo

There is an increasing demand for robust, affordable, and sensitive analytical devices for clinical diagnostics. Herein, we describe a simple route to produce biodegradable and disposable thermoplastic composite electrodes using the commercial polymer (Ecoflex (R)) and graphite microparticles. The surface of the carbon composite electrode was modified with gold nanoparticles conjugated with graphene quantum dots (Au@GQDs) for sensitive and non-enzymatic glucose sensing. The morphological and structural characterizations of the modified electrochemical device revealed a hydrophilic rough composite surface, with high dispersion of graphite in the polymer matrix and confirmed the successful superficial modification of the working electrode with spherical Au@GQDs nanoparticles. Cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) were used to electrochemically characterize the modified and nonmodified thermoplastic sensor, demonstrating a 4.5 fold enhancement of the electroactive area, higher heterogeneous electron transfer kinetics, and electrocatalytic properties for glucose sensing when the sensor was modified with Au@GQDs. The electrochemical determination of the glucose was carried out using an amperometric method applying-0.15 V in alkaline conditions (0.1 mol L-1 NaOH). Under optimized conditions, the proposed method presented a high sensitivity (4.85 A L mol(-1)) and a low limit of detection (LOD) of 9.12 mu mol L-1. The Ecoflex:graphite/Au@GQDs sensor was applied for glucose sensing in synthetic saliva samples with recovery values ranging from 97.84% to 105.20%, highlighting the excellent accuracy of the proposed method. Finally, the electrode was subjected to thermal and biological degradation studies and presented disposable and eco-friendly characteristics. Based on these results, we believe that this new thermoplastic composite sensor modified with Au@GQDs can be an excellent candidate for a disposable, low-cost, and enzymeless electrochemical glucose sensor. (AU)

• Processo FAPESP: 18/08782-1 - Sensores químicos miniaturizados e integrados: novas plataformas de fabricação para aplicações biológicas, clínicas e ambientais
• Beneficiário: Mauro Bertotti
• Modalidade de apoio: Auxílio à Pesquisa - Temático
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• Beneficiário: André Lopes Ferreira
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 18/04061-8 - Filmes automontados de polipirrol e nanopartículas de magnetita na determinação analítica de parabenos
• Beneficiário: Lucas Felipe de Lima
• Modalidade de apoio: Bolsas no Brasil - Mestrado