Synthetic Melanin Films as Potential Interfaces for Peroxynitrite Detection and Quantification

Peroxynitrite (PON) is a highly reactive oxygen-nitrogen species that facilitates both oxidation and nitration reactions. Early reports have revealed the deleterious effects of PON on DNA, proteins, and lipids. Recent studies have suggested that melanin can act as an antioxidative therapy to scavenge the reactive oxygen-nitrogen species (RO-NS) including PON. Melanin is a natural pigment that has many physiological functions involving the neutralization of highly oxidative species. In this project, the interaction between PON and synthetic melanin has been studied. In addition, the electrochemical characteristics of the polymerized 5,6-dihydroxy indole (DHI) as a model of synthetic melanin were examined using cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The ultraviolet-visible (UV-Vis) spectroscopy showed a significant difference in the absorbance of PON alone and in the presence of melanin films. Finally, we report on the possibility of using the DHI-melanin film as a platform for the quantitative detection of PON in solutions