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Electrochemical immunosensor for improved diabetic retinopathy diagnosis in minimally invasive biological fluids

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Resumo:Diabetic retinopathy (DR) is one of the most common diabetes mellitus (DM) complications, that affects the retina and can lead to blindness. In 2017, it was estimated that approximately 150 million people suffered from this disease, and a rising tendency of around 30 % is expected until 2030. Available DR treatments are inefficient on halting disease progression in a significantly high percentage of people. Conventional DR diagnostics relies on qualitative, expensive and complex imaging methods. Technologies that enable an in situ quantitative analysis of DR’s impact do not exist, until this moment, in the market, thus revealing the potential and motivation for the present investigation. The use of minimally invasive biological fluids (like tears and saliva) for studying DR’s potential biomarkers is preferred to the highly invasive ocular fluids currently analyzed on clinical research. However, it is necessary to develop methods with high sensitivity and selectivity in minute sample volumes. The concentrations of IL-6 and MMP2, two biomarkers associated with DR, were assessed on the tears of controls and DR patients, using the Luminex protein quantification method, and statistically significant increased levels were found in case of disease. These results were provided by a close collaborative work with the University of Coimbra. Immunosensors for the detection of each biomarker were developed, in concentrations considered relevant for the diagnosis of DR in tears, primarily using standard solutions. Antibodies were used as specific biorecognition elements, and cyclic voltammetry and electrochemical impedance spectroscopy were used for their detection and quantification. The presented biosensors further revealed to be the only technology adequate for all tear sampling methods, quantifying both biomarkers in DR critical concentrations, using only 1 μL of sample. As a complementary study, the IL-6 sensor was tested in saliva samples, and its analytical profile was compared with the Enzyme-linked immunosorbent assay (ELISA) protein quantification method. The biosensor achieved similar results in ELISA-detectable concentrations, and an ability to quantify concentrations lower than this method’s limit of detection. Therefore, this work presents a novel technology, that may be integrated in point-of-care analytical devices for an in situ diagnosing and monitoring of DR, thus building a foundation for future work, with great potential for technology transfer.
Autores principais:Vieira, Maria Santos Crispiniano
Assunto:Biomarkers Biosensor Diabetic retinopathy Point-of-care Biomarcadores Biossensor Retinopatia diabética
Ano:2021
País:Portugal
Tipo de documento:dissertação de mestrado
Tipo de acesso:acesso aberto
Instituição associada:Universidade do Minho
Idioma:inglês
Origem:RepositóriUM - Universidade do Minho

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