Melanin system composition analyzed by XPS depth profiling

The melanins are a class of natural pigments ubiquitous throughout the biosphere. These gaining significant attention as advanced materials due to their biocompatibility, optical and electrical properties. most common form melanin, eumelanin, has well-known problem insolubility in solvents. made standard chemical analysis challenging, leading researchers opting use X-Ray photoelectron spectroscopy (XPS). However, XPS used on related have been limited being surface technique, hence reported values date may not reflect bulk. In this work, we investigated with depth-profiling method information bulk powder thin-films eumelanin several melanin derivatives. latter derivatives modified designed overcome systems. Our result indicates that there only few differences composition structure between bulk, for either film samples. results show basic probe is sufficient obtain an accurate elemental As such, our characterization important polyindolequinone systems general such polydopamines.