Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, Osaka, Japan.
Graduate Course of Human Health Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Photochem Photobiol Sci. 2024 Sep;23(9):1627-1639. doi: 10.1007/s43630-024-00611-9. Epub 2024 Sep 8.
Photodynamic diagnosis and therapy (PDD and PDT) are emerging techniques for diagnosing and treating tumors and malignant diseases. Photoproducts of protoporphyrin IX (PpIX) used in PDD and PDT may be used in the diagnosis and treatment, making a detailed analysis of the photoproduct formation under various treatment and diagnosis conditions important.Spectroscopic and mass spectrometric analysis of photoproduct formation from PpIX dissolved in dimethyl sulfoxide were performed under commonly used irradiation conditions for PDD and PDT, i.e., wavelengths of 405 and 635 nm and fluence rates of 10 and 100 mW/cm. Irradiation resulted in the formation of hydroxyaldehyde photoproduct (photoprotoporphyrin; Ppp) and formyl photoproduct (product II; Pp II) existing in different quantities with the irradiation wavelength and fluence rate. Ppp was dominant under 635 nm irradiation of PpIX, with a fluorescence peak at 673 nm and a protonated monoisotopic peak at m/z 595.3. PpIX irradiation with 405 nm yielded more Pp II, with a fluorescence peak at 654 nm. A higher photoproduct formation was observed at a low fluence rate for irradiation with 635 nm, while irradiation with 405 nm indicated a higher photoproduct formation at a higher fluence rate.The photoproduct formation with the irradiation conditions can be exploited for dosimetry estimation and may be used as an additional photosensitizer to improve the diagnostics and treatment efficacies of PDD and PDT. Differences in environmental conditions of the present study from that of a biological environment may result in a variation in the photoproduct formation rate and may limit their clinical utilization in PDD and PDT. Thus, further investigation of photoproduct formation rates in more complex biological environments, including in vivo, is necessary. However, the results obtained in this study will serve as a basis for understanding reaction processes in such biological environments.
光动力诊断和治疗（PDD 和 PDT）是用于诊断和治疗肿瘤和恶性疾病的新兴技术。PDD 和 PDT 中使用的原卟啉 IX（PpIX）的光产物可用于诊断和治疗，因此详细分析各种治疗和诊断条件下的光产物形成非常重要。在 PDD 和 PDT 常用的辐照条件下，即 405nm 和 635nm 波长和 10mW/cm 和 100mW/cm 的辐照率，对溶解在二甲亚砜中的 PpIX 的光产物形成进行了光谱和质谱分析。辐照导致羟基醛光产物（原卟啉；Ppp）和甲酰基光产物（产物 II；Pp II）以不同的量形成，其与辐照波长和辐照率有关。在 PpIX 以 635nm 辐照下，Ppp 占主导地位，荧光峰在 673nm，质子化单同位素峰在 m/z 595.3。用 405nm 辐照 PpIX 产生更多的 Pp II，荧光峰在 654nm。在 635nm 辐照下，低辐照率下观察到更高的光产物形成，而在 405nm 辐照下，在更高的辐照率下观察到更高的光产物形成。在目前研究的环境条件下，光产物的形成可能会用于剂量估计，并可作为额外的光敏剂，以提高 PDD 和 PDT 的诊断和治疗效果。与生物环境相比，目前研究的环境条件差异可能导致光产物形成速率的变化，并可能限制其在 PDD 和 PDT 中的临床应用。因此，有必要在更复杂的生物环境中，包括在体，进一步研究光产物形成速率。然而，本研究获得的结果将为理解此类生物环境中的反应过程提供基础。
