Calculation of Cuticle Step Heights from AFM Images of Outer Surfaces of Human Hair

Atomic force microscopy (AFM) is an ideal technique for noninvasive examination of hair surfaces (1 –11 ), providing a wealth of structural information not always apparent from electron microscopy. The fine cuticular structure of human head hair is of interest to those engaged in the fields of dermatology (12 –14 ), cosmetics (15 –17 ), and forensic science (18 –20 ). In the former, the morphology of hair can be affected by an underlying inherited or congenital metabolic disorder, such as maple syrup urine disease (21 ) or monilethrix (22 ), respectively. The cosmetics industry is interested in the effects of haircare formulations, such as conditioning and bleaching agents, on hair cuticle surfaces (23 ). There is now increasing legislation on cosmetic manufacturers to be able to substantiate claims made concerning their products.