X-ray photoelectron spectroscopic study of silk fibroin surface

X-ray photoelectron spectroscopy (XPS) has been used to probe the nature of silk fibroin surface, in particular the tyrosine content and sulfur species on the surface. The iodine labelling treatment of silk, followed by XPS surface analysis, reveals that silk fibroin has a tyrosine-enriched surface, and that there are sulfur-containing amino acids present on the surface, mainly occurring in the S6+ component. UV/ozone treatment modifies/removes the surface tyrosine- and sulfur-containing species. © 2002 Society of Chemical Industry