Figure 1
Top-down whole-organism screening of a library of 38 fluorescent dyes.
(a) Schematic diagrams of a top-down (left) and a bottom-up screening (right). (b) Photographs of the locations of interscapular brown adipose tissue (BAT) and white adipose tissue (WAT). In the intact mouse (left), ROI1 (region of interest) in red dashed triangle represents BAT location and ROI2 (blue circle) represents the areas of BAT, WAT and adjacent non-adipose tissue area. The WAT that covers BAT can be seen after skin removal (middle) and the triangular shape of BAT (black arrow) can be clearly seen after the removal of skin and WAT (right). (c) Quantitative analysis of the top-down screening results. In the graph, each number represents a dye and each dye has three fluorescence signal readouts. The quantification was conducted using the ratio of the average fluorescence intensity of ROI1/ROI2 and the threshold was set at 1.10 (red dashed line). Four hits (black arrow) were selected for re-testing validation. (d) Representative near-infrared (NIR) fluorescence images of the screened dyes. CRANAD-2, CRANAD-3, LDS 722 and Rhodamine 640 showed apparent signal at the interscapular BAT area. Nile blue showed negative contrast for BAT. (e) Chemical structure of CRANAD-2 and -3.
