Fig. 3.
Deep brain vasculature imaging with Q820@BSA labeling. (a) The 3D reconstruction of the brain vasculature via 2-photon fluorescence imaging with excitation at 1650 nm, and the corresponding third-harmonic generation (THG) images with scale bar at 100 µm. The scale bar is 100 μm. (b) THG signal decay curve plotted on a semi-log scale for calculating the effective attenuation lengths in the neocortex and the white matter layer. The straight lines are linear fitting results for calculating the effective attenuation length . The effective attenuation length measured from THG signal is around 370 µm in neocortex and 175 µm in the white matter area. (c) Quantification of the signal-to-background ratios in deep 2-photon fluorescence images over 1 mm. Upper panel: Normalized images at 1000 µm and 1600 µm depths. (Left) 2-photon fluorescence image of a brain vessel at 1000 µm depth; (Right) 2-photon fluorescence image of a brain vessel at 1600 µm depth. Lower panel: Line profiles of the normalized signals along the colored lines shown in the upper panel, with the y-axis in log scale. The scale bar is 100 µm.