McMullen Roger L, Chen Susan, Moore David J
Materials Science Dept., Corporate R&D, International Specialty Products, Wayne, NJ, USA.
J Cosmet Sci. 2011 Mar-Apr;62(2):191-202.
Hair is frequently exposed to environmental stresses and chemical insults that result in damage to its internal structure and its outer cuticular components. Spectrofluorescence is a useful tool to monitor the health of biological tissues as it can measure the level of tryptophan (Trp), which is representative of protein integrity. In addition to Trp fluorescence, several other fluorophores are also present in hair and are believed to be attributed to kynurenenine, N-formylkynurenine, and 3-hydroxykynurenine, which are known metabolic and degradation products of Trp that are affected by environmental stresses normally experienced by hair. In this work, we were able to construct an endogenous fingerprint of fluorescent compounds present in hair by employing a range of excitation wavelengths from 270 nm to 450 nm with a resolution of 2 nm. As a result, we generated surface plots of fluorescence emission as a function of excitation and emission wavelengths (excitation-emission matrices). Thus, we were able to profile the levels of various structural molecules in hair before and after exposure to UV irradiation and thermal straightening irons as well as to chemical treatment such as bleaching and straightening.
头发经常受到环境压力和化学损伤，这些会导致其内部结构和外部角质层成分受损。光谱荧光是监测生物组织健康状况的一种有用工具，因为它可以测量色氨酸（Trp）的水平，而色氨酸代表蛋白质的完整性。除了Trp荧光外，头发中还存在其他几种荧光团，据信它们归因于犬尿烯酸、N-甲酰犬尿氨酸和3-羟基犬尿氨酸，这些是Trp已知的代谢和降解产物，会受到头发通常所经历的环境压力的影响。在这项工作中，我们能够通过采用一系列从270nm到450nm、分辨率为2nm的激发波长，构建头发中存在的荧光化合物的内源性指纹图谱。结果，我们生成了作为激发波长和发射波长函数的荧光发射表面图（激发-发射矩阵）。因此，我们能够描绘出头发在暴露于紫外线照射、热直发器以及漂白和拉直等化学处理之前和之后各种结构分子的水平。
