Desenvolvimento de dispositivo microfluídico descartável contendo arranjos de biossensores para a determinação multiplexada de espécies de interesse biológico em diferentes matrizes
Fava, Elson Luiz
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16 sensing points for the construction of an array of biosensors. The components of this device have been individually evaluated and their construction design has been optimized for the best performance of the sensors. Once the good performance of µPBDMA was proven, the construction of the biosensor was then carried out to determine D-(+)-Glucose. Using the cyclic voltammetry technique for a D-(+)-Glucose Glucose solution, the highest peak currents obtained were for films containing carbon black CB, thus selecting this carbon nanomaterial in the manufacture of the biosensor. The analytical curve obtained showed a linear response range for D-(+)-Glucose concentrations from 0.1 to 40 mmol L-1, and a detection limit of 0.03 mmol L-1, showing the success of the proposed architecture of the built biosensor, being later used for the consolidation of the project proposal which is the analysis multiplexing using the µPBDMA. As an alternative to the enzymatic method for the determination of creatinine, a sensor was developed based on the complexation of the Fe3 + ion with the analyte, thus indirectly determining the concentration of creatinine in the sample by differential pulse voltammetry, monitoring the reduction of free Fe3 + (not complexed) to Fe2 +. This architecture was successfully applied on two platforms, using a low volume device (3 µL), obtaining a linear working range for creatinine (CNN) from 0.1 to 6.5 mmol L-1, with a limit detection of 0.043 mmol L-11. In µPBDMA, studies were performed sequentially with D-(+)-Glucose, creatinine and uric acid, obtaining linear ranges from 0.625 to 20 mmol L-1 for D-(+)-Glucose, from 0.106 to 4.500 mmol L-1 for creatinine and 0.047 to 3.000 mmol L-1 for uric acid, with detection limits of 0.12, 0.084 and 0.012 mmol L-1 for D-(+)-Glucose, creatinine and uric acid, respectively. Repeatability studies of the proposed system were carried out, with RSDs of less than 6.25% being obtained. Studies on the influence of potential interferents were also investigated, with the RDSs being less than 8.25%. In addition, the performance of µPBDMA was assessed using urine samples, obtaining recoveries between 97.4 and 104% for all biomarkers. A microfluidic device coupled to an immunosensor was also developed to detect high levels of PSA. For the use of this system, it was adapted to a Spinner, a toy that has a central bearing to rotate it around its axis. For this, a base with a rod was used and fixed to the Spinner bearing to use it as a centrifuge. This system was developed to load the solutions from the injection point to the disposal point and to separate the blood serum and red blood cells in capillary tubes. The results obtained for the determination of PSA by the immunosensor proved to be promising, given the good linear range obtained (0.5 to 25.0 ng mL-1), and also the detection limit (0.0014 ng mL-1) . The performance of the immunosensor was verified for synthetic human serum fortified with three different concentrations of PSA, obtaining good recoveries of the analyte.
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