Development of a system for type 2 diabetes mellitus early diagnosis

Author(s)

Laís Canniatti Brazaca

• Document type: Master's Dissertation
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Física de São Carlos
• Defense date: 25 fev. 2015

Examining board members

Valtencir Zucolotto; Débora Gusmão Melo; Alexandre da Costa Pereira

• Advisor: Valtencir Zucolotto

Abstract

Obesity has increased dramatically in the last few years, becoming the biggest risk factor for development of cardiovascular diseases, several types of cancer and also the type 2 diabetes mellitus (DM 2). The association between obesity and DM 2 can be partially explained by the altered secretion of adiponectin hormone by the adipose tissue, which presents anti-inflammatory and insulin sensitizing properties. The excess of adipose tissue regulates negatively adiponectin secretion, which occurs 10 to 20 years before chronic hyperglycemia, making this hormone a great biomarker for predictive DM 2 diagnosis. Adiponectin plasma concentration is usually measured by ELISA, a method not widely used due to its high cost, personal and material demand, being, therefore, not accessible to part of the population. Therefore, the development of new diagnostic methodologies and tools trustable and low-cost (that can be implemented by Sistema Único de Saúde SUS) is crucial. Here we developed a simple and low-cost biosensor for adiponectin detection based on electrochemical impedance spectroscopy (EIS) or cyclic voltammetry (CV) using nanostructured platforms containing adiponectin transmembrane receptors (AdipoR1 and AdipoR2) or anti-AdipoQ antibodies immobilized on gold electrodes. The best results were achieved using AdipoR1/R2 receptors among with CV. In this case, biosensors were able to detect adiponectin at concentrations down to 7 nmol L-1 in a linear detection range from 0.01 to 0.75 mol L-1 of adiponectin, R²=0.992. The device displayed great selectivity, stability and reproducibility (ca. 1.7% for n=3). For human plasma samples, analyses using the biosensor and the ELISA technique presented similar results, with deviations of 14%. Therefore, we expect that this study leads to a greater accessibility to predictive DM 2 diagnoses through cheaper, faster and portable devices, so that a higher number of patients may be alerted and oriented, avoiding further disease development. (AU)

• FAPESP's process: 13/10608-6 - Development of a system for type 2 diabetes mellitus early diagnosis
• Grantee: Laís Canniatti Brazaca
• Support type: Scholarships in Brazil - Master