Desenvolvimento de dispositivos eletroquímicos descartáveis e reutilizáveis para detecção de biomarcadores de interesse clínico

Abstract

In recent years, the search for new electrochemical devices that allow reliable, fast, easily accessible, highly sensitive, miniaturized and portable analyses has been required. Furthermore, they enable point-of-care analysis, which allows decentralized clinical monitoring, which decreases the cost and provides an improvement in the quality of health life of the human being. In this context, the first chapter details the development of a low-cost, easy-to-produce disposable electrochemical sensor composed of a conductive ink modified with Prussian blue for the enzymatic and non-enzymatic detection of the biomarker’s uric acid, hydrogen peroxide and glucose. The sensor developed was applied as a wearable sensor in a 3D-printed device for real-time monitoring of synthetic biological fluid. The estimated cost per sensor and biosensor unit was R$4.71 and for the biosensor it was R$6.89, which makes these platforms attractive compared to traditional laboratory tests. The second chapter deals with the development of an electrochemical sensor and immunosensor for the detection of L-Cysteine (L-Cys) and the Spike protein of the SARS-CoV-2 virus. The applicability of the immunosensor for detecting the Spike protein was proven in synthetic saliva samples, thus demonstrating its efficiency in relation to the gold standard RT-PCR technique. Low LODs were demonstrated for L-Cys (0.7 μmol L−1) and Spike protein (0.7 and 1.0 pmol L−1). The third chapter describes the use of fallen tree leaves from the Persea americana Mill species as a substrate for the manufacture of electrochemical sensors using CO2 lasers. The application of the sensor for the detection of dopamine (DA) showed interesting analytical characteristics such as good repeatability and reproducibility, with values of 1.46% and 6.47%, respectively. The use of this type of substrate presents an innovative and high-potential approach as a sustainable and ecological alternative to traditional sensor substrates. Finally, the fourth chapter describes how to obtain easy-to-produce, reusable and low-cost platforms for the development of analytical devices with characteristics suitable for multiplexed analysis. The detection of L-Dopa and DA showed low LOD values of 0.11 and 0.26 µmol L−1, respectively. In this way, it is hoped that the new devices presented here will help make diagnoses more accessible and more cost-effective for the population.