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Updated: May 31, 2026
Multiphoton Intravital Imaging for Monitoring Leukocyte Recruitment during Arteriogenesis in a Murine Hindlimb Model
Published on: September 30, 2021
Time-resolved detection enables standard two-photon fluorescence microscopy for in vivo label-free imaging of
Dong Li1, Wei Zheng, Wei Zhang
1Biomedical Engineering Program, Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong, China.
Abstract:
We conducted a systematic study on two-photon excited fluorescence (TPEF) of hemoglobin using the near transform-limited and Gaussian-shaped femtosecond pulse sources. We found that the two-photon action cross section of hemoglobin drops over 2 orders of magnitude in the wavelength range from 550 to 800 nm, while the spectral and temporal characteristics of hemoglobin TPEF are insensitive to the change of excitation wavelength. In particular, our new findings showed that the hemoglobin fluorescence could be excited with sufficient efficiency using a conventional Ti:sapphire laser tuned at the wavelength close to 700 nm. With the employment of a time-resolved detection method, we demonstrated that the TPEF signals of hemoglobin excited by a Ti:sapphire laser could be clearly differentiated from other nonlinear signals presented within the living biological tissues, indicating that a standard TPEF microscope can become a routine tool for in vivo label-free microangiography imaging.
