Development of a Methodology for Evaluating the Internal Porosity of Hair Through Scanning Electron Microscopy Images.

Author: Angela Cristina Vargas Calle*; Viviane Albarici; Cristina Moreira; Leslie Laquieze; Adriano Pinheiro.

Published at: June 01, 2025

https://kosmoscience.com/pdf/development-of-a-methodology-for-evaluating-the-internal-porosity-of-hair-through-scanning-electron-microscopy-images.pdf

The investigation of hair porosity and the effect of cosmetic products on this parameter for claim substantiation has traditionally relied on indirect measurements. This is primarily because the techniques available for direct assessment require specialized and expensive equipment, making them unfeasible for routine commercial use. However, understanding and addressing hair porosity is critical for cosmetic companies, as it directly impacts the overall integrity of the hair fiber and influences consumer satisfaction. Porosity affects how well hair retains moisture and how it responds to treatments, which is crucial for the long-term performance of hair care products.

Recently, with the advancement of image analysis software and plugins, new methods have emerged to more directly evaluate hair porosity. One promising approach is the use of cross-sectional images of hair fibers obtained through SEM (Scanning Electron Microscopy). This method allows to measure the internal porosity of the hair fiber, offering a more direct and precise analysis. However, the main challenge lies in obtaining high-quality transverse cuts of the hair that preserve the internal structure for accurate measurements.

Given these developments, the goal of this study is to establish a reliable, cost-effective methodology for measuring the number and size of pores in hair fibers. The proposed methodology involves obtaining precise hair cross-sections using advanced histological techniques, followed by image analysis through specialized plugins to count and measure the pores.

The development process was divided into two phases. First, we investigated the most effective combination of embedding medium and cutting tools to produce cross-sections that maintain the hair’s internal morphology. In the second phase, the methodology was validated for reproducibility and its ability to differentiate between various cosmetic treatments.