Development of dry-state SERS substrates for the noninvasive detection of artistic dyes in textiles

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for the detection of natural dyes, allowing one to overcome limitations conventional spectroscopy, i.e., weakness signals and intense fluorescence background. In artistic field, noninvasive approach recommended; however, SERS still an inherently invasive method, requiring extraction analyte or close contact with object wet substrate. Inexpensive easy-to-produce substrates dry-state measurements were fabricated, exploiting only electromagnetic interaction between nanostructured substrate dye molecules absorbed onto textile. To this aim, different developed starting from two colloids (silver nanospheres nanostars) immobilized functionalized microscope glass slide, some parameters connected their synthesis optimized obtain great enhancement signal in dry conditions. Finally, spectra four dyes successfully obtained reference dyed wool threads.