A comparative study between AFM and SEM imaging on human scalp hair

Area of Science:

• Materials Science
• Biophysics
• Microscopy Techniques

Background:

• Accurate surface characterization of biological samples like human hair is crucial for understanding its properties.
• Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) are common imaging techniques, but their preparation methods differ.
• Potential artifacts introduced during sample preparation for SEM could affect the interpretation of surface morphology.

Purpose of the Study:

• To comparatively analyze Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) imaging of the same human scalp hair area.
• To identify similarities and differences between AFM and SEM in visualizing hair surface topography.
• To evaluate the impact of sample preparation procedures, particularly metallization for SEM, on hair surface characteristics.

Main Methods:

• Comparative imaging of identical human scalp hair areas using both AFM and SEM.
• AFM was employed to assess surface topography without specific sample treatments.
• SEM analysis involved standard preparation, including metallization and vacuum exposure.

Main Results:

• AFM analysis indicated that the metallization process for SEM imaging induces significant modifications to the hair surface.
• These modifications include an increase in the height of scale steps and root mean square roughness.
• Variations in scale profiles were observed, directly attributable to sample treatments for SEM.

Conclusions:

• Sample preparation for SEM, particularly metallization, can introduce artifacts that alter the native surface topography of human scalp hair.
• AFM is a valuable tool for evaluating the effects of sample manipulation due to its ability to image without extensive pre-treatment.
• Researchers should consider potential sample modification when interpreting SEM images of hair and similar biological samples.