Non-Invasive Evaluation of Hair Interior Morphology by X-Ray Microscope

The study explored the use of newly-developed X-ray microscopy with an 80–100 nm spatial resolution to evaluate the interior morphology of hair without the artificial changes caused by traditional methods like SEM and TEM. The researchers applied various treatments (UV irradiation, heating, dyeing, bleaching, and permanent waving) to Japanese standard hair tress No. 8 and found that X-ray microscopy provided more intact images of the hair cuticle and fine cracks in the cortex compared to TEM. The internal morphological changes observed included coarsening of cuticles and dehydration of the cortex and medulla. Despite some limitations in resolution compared to TEM, X-ray microscopy showed promise as a non-invasive tool for detailed hair analysis.