Effects of ultraviolet B radiation on physicochemical properties of human hair shaft

Abstract

Changes in physicochemical properties of the human hair shaft induced by UVB during the summer climate were investigated. Using atomic force microscopy and thermogravimetric analyzer measurements, we investigated the changes in hair shaft physical properties including morphology, roughness, and water content. The changes in chemical properties were investigated by using FTIR spectroscopy. Hair samples from 20 females without any chemical or physical stresses were investigated. The samples were exposed to various UVB doses of 400, 2,000, and 4,000 mJ/cm(2), which correspond to the radiation times of 0.44, 2.22, and 4.44 h, respectively. The morphology and surface of the hair shaft was not significantly affected by UVB irradiation. The components of keratin were affected by the UVB irradiation where the amide A bands at 3,263 and 3,246 cm(-1) of the proximal and distal roots, respectively, were shifted to higher band region because α-helix converted to β-sheet, and the stretching modes of C-H lipid alkyl chains at 2,965 and 2,850 cm(-1) in the proximal and distal roots, respectively, were developed. As the UVB intensity increased, the water content of the proximal root decreased.