Atomic force microscopy of human hair

Abstract

Summary:The atomic force microscope (AFM) was used to investigate the surface architecture of the entire lengths of cleaned human head hairs. Many features previously seen with the scanning electron microscope (SEM) were identified. However, the AFM has provided much greater detail and, in particular, the hair's cuticular surfaces appear not to be as smooth as had been previously supposed. A consistent feature was of step discontinuities or "ghosts" on the scale surfaces. These delineated the original location of each overlying scale before its edge had been chipped away. There was a change in the longitudinal angular presentation of the surfaces about each ghost. This means the distal ends of each cuticle cell have been synthesised in the follicle to be thicker than where that same cuticle cell is bounded on both sides by other cuticle cells. The undamaged outer cuticular surfaces at the root end of each hair were covered everywhere by longitudinal ridges (striations). Where the hair surface was worn, the striations terminated at a scale edge ghost. The ridges were approximately 9 nm high and were in parallel array with a lateral repeat spacing of about 350 nm. The striations are evidently formed on the outer surface of each cuticle cell following earlier contact in the hair follicle with the inner root sheath. The study of stained transverse sections of hairs in the transmission electron microscope (TEM) is suggested as a means for throwing some light on the underlying structure and chemistry of the striations. Finally, our AFM studies have revealed that the surface of the freshly emergent hair gradually changes over a distance of about 20 mm and that the surface of the hair for most of its length is quite different from that near the root. This is likely to be of import to those engaged in the hair toiletries industry.

Quantitative analysis and classification of AFM images of human hair

“…A high fit error may imply a high degree of fine-detail irregularity on the cuticle surface due to, for example, surface striations (Swift & Smith, 2000). 8 Cuticle density : the number of cuticles per millimetre.…”

“…One other technique that has been of particular interest recently is atomic force microscopy (AFM) (Binnig et al ., 1986;Rugar & Hansma, 1990). AFM offers a uniquely useful combination of advantages for analysis of the fine surface structure of the outer surface of hair (O'Conner et al ., 1995;Smith, 1997;You & Yu, 1997;Swift & Smith, 2000;Blach et al ., 2001). AFM is a non-invasive technique that requires no special sample preparation.…”

In Vitro Methodologies to Evaluate the Effects of Hair Care Products on Hair Fiber

“…AFM could be applied to get certain hair strain properties, such as Particle deposition over surface and affinity to incorporated ingredients in hair care products [20,24], structural and morphological changes [26,[28][29][30][31] as well.…”

“…Protein loss [11,12,[44][45][46][47][48]; Electrophoresis [13,25]; Scanning Electron Microscopy [5,[19][20][21][22]; Transmission Electron Microscopy [6,24,25]; Atomic Force Microscopy [7,26,[28][29][30][31]; Optical Coherence Tomography [8,33]; RAMAN spectroscopy [10,[32][33][34] Hair Shine-Gloss Diffuse reflectance spectrophotometry [14,33,43,46,50] Easy to comb Combing resistance [12,64,65] Strength properties Resistance to breakage [12,14,16,33,61,62] Photoprotection Photoluminescence spectroscopy [40][41][42][43] Long-lasting color Diffuse reflectance spectrophotometry [14,…”

Structural Changes in Cuticles on Violin Bow Hair Caused by Wear

“…The structure of human hairs has been thoroughly observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). 1,2) Bow hair is gradually worn out by repeated violin playing, resulting in decreased sound quality. However, little investigation has focused on how the cuticles of bow hair are worn down.…”