Development of microelectrodes for monitoring the redox state in inflammation through the electrochemical detection of urate hydroperoxide, ascorbate and urate cells in vitro

Abstract

The inflammation is part of the biological response sought by tissues in response to noxious stimuli. Aiming to eliminate invaders, inflammatory cells produce reactive intermediates such as the superoxide radical (O2 Ï -), hydrogen peroxide (H2O2), hypochlorous acid (HOCl) and organic peroxides (ROOH) via reactions catalyzed by NADPH oxidase and myeloperoxidase. These intermediates are responsible for cell signaling in inflammation, but they can not react in a selective and changing the chemical composition of the nucleic acids, membranes and proteins and are therefore directly related to diseases such as cancer, neurodegenerative diseases and cardiovascular diseases. Myeloperoxidase oxidize chloride to hypochlorous acid and also use other substrates such as catecholamines, amino acids, nitrite, ascorbic acid and uric acid generating oxidants that can cause endothelial dysfunction. Thus, monitoring of the byproducts of the catalytic activity of myeloperoxidase is valuable for understanding the mechanisms of progression of inflammation in chronic disorders. In this context, this project aims at quantifying biomolecules antioxidants such as urate and ascorbate and urate hydroperoxide formed by the oxidation of uric acid and ascorbic acid by myeloperoxidase in the presence of superoxide anion radical. The determination of the concentration of these species can contribute to the understanding of the role of redox processes signaling and promotion of inflammation and cell death. Electrochemical techniques will be employed due to various advantageous features, which include selectivity, sensitivity, reproducibility, easy construction and low cost of the electrodes, besides the possibility of miniaturization and detection of substances into single cells. For monitoring of the compounds of interest, microelectrodes are functionalized with appropriate modifiers, aiming the development of selective and sensitive methods for analysis in cells in vitro.