“…Electron paramagnetic resonance (EPR) studies indicated that o-semiquinone free radicals exist in melanins (Sarna, 1981;Sealy et al, 1982;Shima et al, 1997;Ito and Wakamatsu, 2003;Latocha et al, 2004b;Beberok et al, 2010). EPR spectra of euand pheomelanins differ in shape, and it is used to determine the type of natural melanin in the biological samples and biomaterials (Sarna, 1981;Sealy et al, 1982;Shima et al, 1997;Ito and Wakamatsu, 2003;Latocha et al, 2004aLatocha et al, , 2004bMatuszczyk et al, 2004;Buszman et al, 2006).…”