Production of an Enzymatic Biosensor Containing Laccase Immobilized in Silica Gel Functionalized for Application in the Quantification of L-Dopamine

The development of the present project aims the production of an enzymatic biosensor containing laccase immobilized on a silica gel electrode for quantification of L-dopamine. The objective of this quantification at the future is to monitor several health problems, such as Parkinson's disease, dementia, schizophrenia, depression and heart problems, due to changes in the concentration of L-dopamine in the human body. Thus, during the development of this work, initially it was performed the functionalization process of silica gel through 3-aminopropyltriethoxysilane treatment and, then, the immobilization process of laccase and the biosensor assembly. After this step, potentiometric tests were performed to evaluate the efficiency of the final assembly of the biosensor produced. For this, initially a calibration curve was obtained by the quantification of L-dopamine solutions with different concentrations. After that, the quantification of a solution with an unknown concentration was performed, being possible to validate the results obtained regarding what was expected by the methodology applied. It was also possible to verify that the reverse reaction (reduction) is less expressive than the direct reaction. A calibration curve via HPLC with L-dopamine was also obtained for comparison of the potentiometric data with the chromatographic data, regarding the quantification of L-dopamine, aiming the validation of the results obtained. To conclude, it was possible to verify that the biosensor produced is efficient regarding the quantification of L-dopamine.