We employed deep UV (DUV) Raman spectroscopy for characterization of molecular photodamage in cells. 244 nm light excitation Raman spectra were measured for HeLa cells exposed to the excitation light for different durations. In the spectra obtained with the shortest exposure duration (0.25 sec at 16 µW/µm2 irradiation), characteristic resonant Raman bands of adenine and guanine at 1483 cm−1 and tryptophan and tyrosine at 1618 cm−1 were clearly visible. With increasing exposure duration (up to 12.5 sec), these biomolecular Raman bands diminished, while a photoproduct Raman band at 1611 cm−1 grew. By exponential function fitting analyses, intensities of these characteristic three bands were correlated with sample exposure duration at different intensities of excitation light. We then suggest practical excitation conditions effective for DUV Raman observation of cells without photodamage-related spectral distortion.
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机译：我们采用深紫外（DUV）拉曼光谱来表征细胞中的分子光损伤。对于暴露于激发光不同持续时间的HeLa细胞，测量了244 nm光激发拉曼光谱。在以最短曝光时间（在16 µW / µm 2 照射下为0.25秒）获得的光谱中，腺嘌呤和鸟嘌呤在1483 cm -1 和色氨酸的共振共振拉曼谱带清晰可见1618 cm -1 处的酪氨酸。随着曝光时间的延长（最长12.5秒），这些生物分子拉曼谱带逐渐减少，而1611 cm -1 的光产物拉曼谱带却在增长。通过指数函数拟合分析，在不同激发光强度下，这三个特征谱带的强度与样品暴露持续时间相关。然后，我们提出了对DUV拉曼观察有效的，没有光损伤相关光谱失真的细胞的实际激发条件。
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