多光子成像中的生物组织光损伤  

Photodamage of Biotissue in Multiphoton Imaging

作　　者：梁晓轩 Alfred Vogel 张镇西[2] Liang XiaoXuan;Alfred Vogel;Zhang Zhenxi(Institute of Biomedical Optics,University of Luebeck,Luebeck 23562,Germany;Institute of Biomedical Photonics and Sensing,School of Life Science and Technology,Xi’an Jiaotong University,Xi’an 710049,Shaanxi,China)

机构地区：[1]德国吕贝克大学生物医学光学研究所,德国吕贝克23562 [2]西安交通大学生命学院生物医学光子学与传感研究所,陕西西安710049

出　　处：《中国激光》2023年第3期14-30,共17页Chinese Journal of Lasers

基　　金：中德合作交流项目(M0063);国家自然科学基金(61727823,61875159)。

摘　　要：多光子激发荧光成像技术因低侵入性、强穿透力、高信噪比和高空间分辨率在生物医学光学领域得到广泛的应用,同时也成为最重要的研究工具之一。在多光子成像中过量的光子密度或激光功率会引起生物组织光损伤。光损伤决定了成像所能使用的激光功率的上限。光损伤强度与激光、组织光学参数有关,其背后的作用机制可分为光化学作用和光热作用。重点论述了光损伤的基本原理和形成机制,阐述了光损伤分析数学模型。讨论和分析了不同组织、不同波长下光损伤的一些研究进展。总结了光损伤规律:无色素组织双光子成像中光损伤以光化学作用为主,色素组织双光子成像中光损伤以光热作用为主,三光子深层组织成像中光损伤很可能来自光化学和光热协同作用。展望了降低光损伤和优化成像参数的可行策略。Significance Multiphoton excitation fluorescence imaging is widely used in the field of biomedical optics and has become one of the most important research tools due to its low invasiveness,strong penetration,high signaltonoise ratio and high spatial resolution.Photodamage in biological tissues can be caused if excessive photon density or laser power is applied during imaging.While signaltonoise ratio determines the lower limit of laser power that can be used in multiphoton imaging,photodamage delineates its upper boarders.For invivo labelfree imaging,due to the small cross section of endogenous fluorophores(≈10-2 GM),the tunability range of laser power between nondestructive imaging and photodamage is very narrow.Therefore,a reasonable laser power is required to ensure that multiphoton imaging with sufficient information can be obtained,and that the cells or biological tissues remain functionally active after long time irradiation.Reducing photodamage and optimizing imaging parameters is one of the major challenges in multiphoton imaging.Photodamage studies are essential to the optimization of imaging parameters.Progress Photodamage can be intuitively understood by the concept of ionization penalty in multiphoton bioimaging(Fig.1).Ionization penalty occurs at irradiance of about 2×1012 W/cm2,where,for a single fluorescence photon emitted from fluorophores,a free electron is produced from water.The chemicals arising from ionization of water molecules can be detrimental to biomolecules and tissues.The underlying mechanisms behind photodamage can be generally divided into photochemical and photothermal effects,as illustrated in Fig.2.For photochemical effects,they can be further divided into UVA like photooxidation effect and plasmamediated chemical effect that is wavelengthindependent.The severity of photodamage is related to the laser parameters and optical parameters of biotissue.To evaluate the cause of photodamage,the stateoftheart numerical tools are summarized,including a refined multirateequation model t

关 键 词：生物光学 多光子激发荧光成像 光损伤 光毒性 光化学作用 光热作用 

分 类 号：O437[机械工程—光学工程] Q631[理学—光学]