Penetration pathways of fluorescent dyes in human hair fibres investigatedby scanning near-field optical microscopy

Thin cross-sections of human hairs were investigated by scanning near-field optical microscopy (SNOM) and confocal laser scanning microscopy (CLSM) af ter penetration of a fluorescent dye. The same samples were measured with b oth techniques to compare the observed structures. The images obtained from the two methods show nearly identical structures representing pathways of the dye molecules in hairs. The SNOM images provide a higher resolution tha n the CLSM images. Therefore, SNOM is believed to be a suitable method for investigations at a resolution of 100 nm on penetration pathways of fluores cent dyes such as the cell membrane complex pathway in cross-sections of ha irs.