Fig. 4

In vivo visualizing the microvasculature map of the flap. A–D Time course of bright field images in a flap perfusion defect animal model at different time points after injection of RNase A@PbS/ZnS QDs. E–H Time course of corresponding NIR-II fluorescence images. The area of the perforator flap was marked by the green dotted line, and the red dotted line marked the boundary between the bright zone and the dark zone; the yellow dashed line indicated the perforator vessel and the green dashed line indicated the choke vessel. Quantitative measurement of the diameter of the perforator vessel (I) and the choke vessel (J). K The area ratio between bright zone and total zone. L The fluorescence intensity analysis of the four perforasome