Department of Mechanical Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea.
Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk, 37673, Republic of Korea.
Sci Rep. 2018 Jun 20;8(1):9415. doi: 10.1038/s41598-018-27371-8.
Moxifloxacin is an antibiotic used in clinics and has recently been used as a clinically compatible cell-labeling agent for two-photon (2P) imaging. Although 2P imaging with moxifloxacin labeling visualized cells inside tissues using enhanced fluorescence, the imaging depth was quite limited because of the relatively short excitation wavelength (<800 nm) used. In this study, the feasibility of three-photon (3P) excitation of moxifloxacin using a longer excitation wavelength and moxifloxacin-based 3P imaging were tested to increase the imaging depth. Moxifloxacin fluorescence via 3P excitation was detected at a >1000 nm excitation wavelength. After obtaining the excitation and emission spectra of moxifloxacin, moxifloxacin-based 3P imaging was applied to ex vivo mouse bladder and ex vivo mouse small intestine tissues and compared with moxifloxacin-based 2P imaging by switching the excitation wavelength of a Ti:sapphire oscillator between near 1030 and 780 nm. Both moxifloxacin-based 2P and 3P imaging visualized cellular structures in the tissues via moxifloxacin labeling, but the image contrast was better with 3P imaging than with 2P imaging at the same imaging depths. The imaging speed and imaging depth of moxifloxacin-based 3P imaging using a Ti:sapphire oscillator were limited by insufficient excitation power. Therefore, we constructed a new system for moxifloxacin-based 3P imaging using a high-energy Yb fiber laser at 1030 nm and used it for in vivo deep tissue imaging of a mouse small intestine. Moxifloxacin-based 3P imaging could be useful for clinical applications with enhanced imaging depth.
莫西沙星是一种临床应用的抗生素，最近被用作双光子（2P）成像的临床兼容细胞标记物。尽管使用莫西沙星标记的 2P 成像可以通过增强荧光来可视化组织内的细胞，但由于使用的激发波长相对较短（<800nm），成像深度非常有限。在这项研究中，测试了使用较长激发波长的三光子（3P）激发莫西沙星和基于莫西沙星的 3P 成像的可行性，以增加成像深度。通过>1000nm 的激发波长检测到莫西沙星的 3P 激发荧光。在获得莫西沙星的激发和发射光谱后，将基于莫西沙星的 3P 成像应用于离体小鼠膀胱和离体小鼠小肠组织，并通过在近 1030nm 和 780nm 之间切换钛宝石振荡器的激发波长来比较基于莫西沙星的 2P 成像。基于莫西沙星的 2P 和 3P 成像都通过莫西沙星标记可视化了组织中的细胞结构，但在相同的成像深度下，3P 成像的图像对比度优于 2P 成像。使用钛宝石振荡器的基于莫西沙星的 3P 成像的成像速度和成像深度受到激发功率不足的限制。因此，我们构建了一个新的基于莫西沙星的 3P 成像系统，使用 1030nm 的高能 Yb 光纤激光，并将其用于小鼠小肠的体内深层组织成像。基于莫西沙星的 3P 成像可能对增强成像深度的临床应用有用。
