SPring-8, the large synchrotron radiation facility

Kracie Home Products, Ltd. succeeded in visualizing the distribution of hair components. As a result, we observed the uneven distribution of hair components that cause “curly hair,” the so-called state of “hair uniformity,” at the microlevel.

Consumers’ concerns with their hair shift from “hair damage” to “hair aging” in their mid-30s. Curliness, waviness, and dryness are high on the list of problems, giving a strong impression of a change in hair type. A well-known change in hair itself with aging is the increase in the curliness of hair. The uneven distribution of proteins in curly hair has been observed using electron microscopes, atomic force microscopes, and X-ray diffraction systems. However, the distribution of lipids that also affect the hair properties and play important roles in hair along with proteins had remained unclear. The research team used the world’s highest performance infrared (IR) microspectroscopy system at SPring-8. The IR microspectroscopy system consisting of a combination of a microscope and an IR spectrophotometer is a tool for measuring the distribution of components in a specific region. Detailed data on the distribution of components in the cross section of hair had not been collected because of the difficulty in observing microscopic regions using general IR measurement apparatuses. Using the IR microspectroscopy system, which enables the simultaneous observation of the distribution of proteins and lipids in hair, the research team carried out measurements on the cross section of hair after determining the optimum conditions for observation and analysis on the basis of the examination of sectioning methods and measurement conditions.

In hair with a nearly round cross section, proteins (amide bonds) and lipids (CH bonds) are uniformly distributed throughout the cross section, indicating that the composition distribution in hair is uniform (Fig. 1). On the other hand, in curly hair, lipids are sparsely distributed (the number of CH bonds is small) in a protein-dense area (where the number of amide bonds is large) and are densely packed in a protein-sparse area (Fig. 2). The research team observed the uneven distribution of components such as proteins and lipids in hair at the microlevel, and succeeded in visualizing a more detailed distribution of components in hair than the conventional distribution.

As described above, the research team revealed the uneven distribution of components in curly hair in which lipids are sparsely distributed in a protein-dense area, the so-called state of hair uniformity, using the new technology for observing hair. The results suggest that the curliness of hair could be improved by correcting the uneven distribution of proteins and lipids in curly hair.

The establishment of this analytical method will lead to the clarification of the site and mechanism of action of lipids, such as oils contained in hair care products, which will be applied to the development of hair care products for correcting the uneven distribution of components in hair. Kracie will apply the achievements of this research to the development of hair care products that will come out next spring.