Figure 4: Fluorescence Lifetime Imaging Microscopy (FLIM) of VMTs.
From: 3D microtumors in vitro supported by perfused vascular networks
(a) Two different tissue chambers are shown in (i) and (ii). For each: EC (red) overlaid on the bright-field image (top left); 2PE-FLIM map of EC forming vessels and wrapped with perivascular cells (top right); Vessel and perivascular cell regions of interest (ROIs) were selected by manual masking and the average NADH phasor in each of these ROIs was calculated for ECs forming vessels (bottom left) and for the perivascular cells (bottom right), as described in Materials and Methods. Scale bar 20 μm. (iii) NADH FLIM phasor distribution used to create the free/bound NADH color scale. (iv) the average phasors for the ECs and the perivascular cells. Error bars show mean ± s.d of 6 replicates (n = 3, p < 0.05). (b) Left: confocal image of MCF-7 breast tumor cells (red) and vasculature (green). Right: 2PE-NADH FLIM map of the same VMT, and the NADH FLIM phasor distribution used to create the free/bound NADH color scale. (c) High resolution 2PE-NADH FLIM map of the tumor shown in (b) demonstrating metabolic heterogeneity, and the NADH FLIM phasor distribution used to create the free/bound NADH color scale.
