A novel GLUT-4 electrochemical immunosensor based on a poly (thionine)-gold nanoparticle nanocomposite: Combining complex capacitance and dissolved oxygen to obtain an analytical signal

Author(s)

Olean-Oliveira, Andre ; Seraphim, Patricia Monteiro ; Portugal, Miqueias L. ; Teixeira, Marcos F. S.

• Document type: Journal article
• Source: BIOSENSORS & BIOELECTRONICS; v. 275, p. 8-pg., 2025-05-01.

Abstract

Detection of glucose transporter 4 (GLUT4) is essential for understanding various physiological and pathological processes. This work reports the development of a novel electrochemical immunosensor for the direct detection of GLUT4, employing dissolved oxygen as a redox probe. This molecular oxygen-sensitive response is mediated by a redox-conductive polymer based on thionine. The sensor platform was fabricated via a one-step electropolymerization of thionine and gold nanoparticles (AuNPs) onto a platinum screen-printed electrode (OleanOliveira et al., 2022a). The immunosensor was then constructed by physical adsorption of a GLUT4 antibody onto the poly(thionine)-AuNP composite surface. This label-free approach eliminates the need for secondary antibodies or enzymes. The immunosensor performance was evaluated using electrochemical impedance spectroscopy (EIS). The sensing mechanism relies on impedance changes; increasing GLUT4 concentrations lead to increased impedance due to enhanced surface blocking upon GLUT4-antibody binding. This interaction impedes oxygen diffusion to the polymer redox sites, resulting in increased electrical resistance. Analysis of the redox capacitance as a function of frequency demonstrates a decrease in the capacitive arc with increasing GLUT4 concentration. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 24/08769-6 - DEVELOPMENT OF A GENOSENSOR BASED ON SILVER NANOPARTICLE ENCAPSULATED IN Pi-CONJUGATED POLYMER FOR MONITORING OF miRNA IN PATHOGENIC CELLS
• Grantee: Miquéias de Lima Portugal
• Support Opportunities: Scholarships in Brazil - Master