Qualitative investigation of fresh human scalp hair with full-field optical coherence tomography

Abstract

Abstract. We have investigated depth-resolved cellular structures of unmodified fresh human scalp hairs with ultrahigh-resolution full-field optical coherence tomography (FF-OCT). The Linnik-type white light interference microscope has been home-implemented to observe the micro-internal layers of human hairs in their natural environment. In hair shafts, FF-OCT has qualitatively revealed the cellular hair compartments of cuticle and cortex layers involved in keratin filaments and melanin granules. No significant difference between black and white hair shafts was observed except for absence of only the melanin granules in the white hair, reflecting that the density of the melanin granules directly affects the hair color. Anatomical description of plucked hair bulbs was also obtained with the FF-OCT in three-dimensions. We expect this approach will be useful for evaluating cellular alteration of natural hairs on cosmetic assessment or diagnosis of hair diseases.

Optical Coherence Tomography in the Evaluation of the Scalp and Hair: Common Features and Clinical Utility

“…Similar findings have been reported in patients with alopecia areata (AA) in whom hair in and surrounding alopecic patches has lower CS compared with hairs on unaffected scalp, though FF is not significantly different [17]. In healthy controls, OCT imaging of ex vivo hair shafts has been shown to clearly identify plucked inner root sheath layers as well as cortical region melanin globules responsible for hair color [18]. OCT has been employed in the evaluation of frontal-fibrosing alopecia (FFA) to show that epidermal thickness is highest in inflamed regions of scalp and lowest in scarred regions, compared with control patients, whereas a paradoxical increase in deep vascular flow alongside a decrease in superficial vascular flow is observed as inflamed scalp progresses to cicatricial stages [19,20].…”

In vivo Optical Coherence Tomography of Light-Driven Melanosome Translocation in Retinal Pigment Epithelium

“…Melanin has a high index of refraction2829, in confocal microscopy images, and thus melanin has been shown to provide strong contrast30. OCT images of brain, skin and hair also indicate higher scatter or increased signal in melanin accumulated area2829313233.…”

In vitro determination of Mexican Mestizo hair shaft diameter using optical coherence tomography

“…Human hair, particularly its structural and morphological features, has been the subject of intense scientific research in dermatology and cosmetics for decades . It is generally classified according to three conventional racial human subgroups, that is Afro‐ethnic, Asian and Caucasian to examine differences in factors such as hair density, diameter, colour, shape and growth parameters .…”