Fig. 7

Enhanced drug delivery efficiency of the PHNs, validated using 3D cellular spheroids. Monitoring the drug penetration depth into the spheroids using R6G@A-PHN under a light exposure and b dark conditions. (i) Z-stack confocal images and maximum intensity projection (MIP) image of a single spheroid. Scale bars indicate 100 µm. The orange color indicates the R6G, and the blue color represents the nucleus in the spheroid. (ii) XY-plane profiles of fluorescent distribution in the spheroid. c Evaluation of delivery efficacy toward 3D spheroid using the released drug (i.e., ptx). (i) Live/dead cell images (Scale bar: 200 µm) and (ii) comparisons of the live/dead cell ratio from individual spheroids (n = 5)