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Updated: Jul 5, 2025

A Bright NIR-II Fluorescence Probe for Vascular and Tumor Imaging
Published on: March 17, 2023
In vivo deep brain multiphoton fluorescence imaging emitting at NIR-I and NIR-II and excited at NIR-IV
Jincheng Zhong1, Yingxian Zhang1, Xinlin Chen2
1Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, China.
Abstract:
Multiphoton microscopy (MPM) enables deep brain imaging. Three optical windows: NIR-I, NIR-II, and NIR-III are widely used. Recently, NIR-IV (the 2200 nm window) has been demonstrated to be the last and longest window for deep tissue MPM. However, so far MPM covers only two optical windows labeled by single fluorescent probe, one for emission and one for excitation. Here we demonstrate in vivo deep brain MPM covering three optical windows, with emission at NIR-I, NIR-II, and excitation at NIR-IV, labeled by ICG. The innovations include: (1) characterizing both 3-photon excitation and emission properties of ICG emitting at both NIR-I and NIR-II, in water, plasma, and circulating blood; (2) a home-built multiphoton microscope with simultaneous dual channel detection, with which we demonstrate deep brain MPM 950 μm (NIR-I) and 850 μm (NIR-II) into the mouse brain in vivo, verifying that multi-optical window MPM is promising for deep brain imaging.

