Electrochemical sensors with a matrix containing graphene quantum dots or nanoribbons for the detection of biomarkers

• Grant number: 19/13514-9
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): February 01, 2020
• Effective date (End): January 31, 2022
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal researcher: Osvaldo Novais de Oliveira Junior
• Grantee: José Luiz Bott Neto
• Home Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 18/22214-6 - Toward a convergence of technologies: from sensing and biosensing to information visualization and machine learning for data analysis in clinical diagnosis, AP.TEM

Abstract

Electrochemical sensors have been studied for the diagnosis of negligible diseases and cancer, however there are still challenges for the commercial production of the devices. One of the possible improvements is in the choice of nanomaterials for the matrix on which the active layer is deposited. In this project, we will use graphene quantum dots (GQDs) or graphene nanoribbons (GRNs) in the matrix for the electrochemical detection of biomarkers, such as prostate specific antigen (PSA), carbohydrate antigen 15-3 (CA 15-3) and vitamin D. The GQDs and GNRs will be synthesized by the Top-Down method. The molecular architectures of the sensors will be investigated by various techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force spectroscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The detection of the biomarkers will be done with electrochemical techniques. Another important objective of this project is to investigate the adsorption and oxidation/reduction mechanisms of the biomarkers, using in situ Fourier transform infrared spectroscopy (FTIR) and in situ frequency summation spectroscopy (SFG). It will be tried to correlate the structure and composition of the electrochemical sensors with their electrocatalytic activity, stability, selectivity and sensitivity.