Research Paper : The Effect of UV-A Irradiation on Morphological Change in Semi Permanent Dyed Human Hair Shaft

Kim, Seo Heui; Cho, Ji Hoon

Journal of the Korean Society of Cosmetology 2014;20(4):721-725.
Published online August 31, 2014.

UV-A조사에 의한 반영구염색모발의 형태학적 변화

김서희, 조지훈

Research Paper : The Effect of UV-A Irradiation on Morphological Change in Semi Permanent Dyed Human Hair Shaft

Seo Heui Kim, Ji Hoon Cho

Abstract

The destruction of an ozone layer caused by environmental pollution brings about the increase of ultraviolet rays. Hair damage mainly occurs in 250 nm~400 nm. While UV is fewer in the number of photon than a visible ray or infrared light, it is higher in photon energy. In order to examine damaged semi-permanent dyed hair shaft associated with UV-A, ultra structure of human hair shaft was observed. UV-A was radiated 600 hours on virgin human hair shaft and treated with a semi-permanent dye(UV-A 360 nm, 7.0W/m2). As a result, virgin human hair shaft was observed other reachers have proposed formal features. cuticle layer that treated with a semi-permanent dye was showed symptom of damages. Cuticular cell was degraded, eliminated and endo cuticle formed with thinner, cavity. Cortex layerwas observed the cavity between the cortical cell and melanin granules. The photochemical destruction of human hair shaft is accelerated by long term irradiation and cosmetic treated hair. It is assumed that hair exposed to UV generates free radical, keratin and melanin are oxidized in the hair, cystine bond is cleaved, cysteic acid is generated, and finally hair damage occurs. Based on this result, common people and cosmetic professionals should recognize and manage photo-damage to maintain and manage healthy hair.

Key Words: Cortical cell, Cuticular cell, Semi Permanent Dye, Ultra structure, Ultra-violet ray