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Atomic force microscopy of human hair
1Department of Fetal and Infant Toxico-Pathology, University of Liverpool, UK. jaswift@gayton.u-net.com
Scanning
|October 7, 2000
Summary
Atomic force microscopy (AFM) reveals human head hair cuticles are not smooth, showing scale discontinuities. These findings offer insights into hair structure relevant to the cosmetics industry.
Area of Science:
- Materials Science
- Biophysics
- Dermatology
Background:
- Previous studies using scanning electron microscopy (SEM) provided insights into hair surface architecture.
- The surface topography of human head hair has been a subject of interest for understanding hair properties.
Purpose of the Study:
- To investigate the surface architecture of human head hairs using atomic force microscopy (AFM).
- To provide greater detail of hair cuticular surfaces compared to previous SEM studies.
- To identify and characterize surface features, including scale discontinuities and longitudinal ridges.
Main Methods:
- Utilized atomic force microscopy (AFM) to analyze the surface of cleaned human head hairs.
- Compared AFM findings with existing scanning electron microscopy (SEM) data.
- Examined surface features such as scale discontinuities ('ghosts') and cuticular ridges (striations).
Main Results:
- AFM revealed greater detail of hair cuticular surfaces, indicating they are not as smooth as previously assumed.
- Consistent 'ghosts' (step discontinuities) were observed, marking the original positions of scale edges.
- Longitudinal ridges (striations) approximately 9 nm high with a 350 nm spacing were found on undamaged hair surfaces near the root.
- The hair surface showed gradual changes over the first 20 mm from the root.
Conclusions:
- The distal ends of cuticle cells are synthesized to be thicker.
- Striations are formed by contact with the inner root sheath in the hair follicle.
- The surface morphology of freshly emergent hair differs significantly along its length, impacting the hair toiletries industry.