Fig. 6

Penetration and retention. A CLSM images of 3D HUVECs cell spheres treated with different C6-labeled formulations. The cell spheres at different depths ranging from 0–90 μm were scanned using the z-stack tool. The bar is 400 μm. B Corresponding quantification of green fluorescence at the depths ranging from 0–350 μm calculated by ImageJ software. C CLSM images of posterior ocular segment sections of SD rats treated with different C6-labeled formulations within 14 days. The white arrows point to the RPE layer. The bar is 400 μm. D Corresponding quantification of green fluorescence in the RPE layer. The quantitative area is selected randomly from the three RPE sites, n = 3. ***P < 0.001