Probing near-infrared photorelaxation pathways in eumelanins and pheomelanins.
Probing near-infrared photorelaxation pathways in eumelanins and pheomelanins.
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DOI：
10.1021/jp103608d
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发表时间：
2010-11-04
影响因子：
2.9
通讯作者：
Warren, Warren S.
中科院分区：
文献类型：
--
作者：
Piletic, Ivan R.;Matthews, Thomas E.;Warren, Warren S.
紫外-可见光谱法很容易辨别两种类型的黑色素（真黑素和褐黑素），尽管关于光学性质和色素异质性的基本细节更难以单独通过分析广泛的无特征吸收光谱来解开。我们采用非线性瞬态吸收光谱研究不同的黑色素在近红外波长。激发态吸收，基态损耗和受激发射信号的贡献进行了区分天然和合成的真黑素和褐黑素。在非线性激发机制中观察到颜料之间的鲜明对比，因为它们都表现出不同的瞬态吸收振幅，相移和非指数种群动态跨越飞秒-纳秒范围。以这种方式，在合成和人类头发样品中区分了褐黑素亚类内的不同色素。这些结果突出了非线性光谱学的潜力，以提供在原位分析的天然黑色素的组织，否则难以提取和纯化。
Ultraviolet-visible spectroscopy readily discerns the two types of melanin pigments (eumelanin and pheomelanin) although fundamental details regarding the optical properties and pigment heterogeneity are more difficult to disentangle via analysis of the broad featureless absorption spectrum alone. We employed nonlinear transient absorption spectroscopy to study different melanin pigments at near infrared wavelengths. Excited state absorption, ground state depletion and stimulated emission signal contributions were distinguished for natural and synthetic eumelanins and pheomelanins. A starker contrast amongst the pigments is observed in the nonlinear excitation regime because they all exhibit distinct transient absorptive amplitudes, phase shifts and nonexponential population dynamics spanning the femtosecond – nanosecond range. In this manner, different pigments within the pheomelanin subclass were distinguished in synthetic and human hair samples. These results highlight the potential of nonlinear spectroscopies to deliver an in situ analysis of natural melanins in tissue that are otherwise difficult to extract and purify.
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影响因子：
1.1
作者：
Lebedev, MV;Misochko, OV;Georgiev, N
通讯作者：
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影响因子：
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Fu, Dan;Ye, Tong;Warren, Warren S.
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作者：
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