Fig. 4

SEM imaging of rat basophilic (RBL) cells cultured with quinacridone nanohedgehogs. a RBL cells cultured on 10-µm-size nanoneedle hedgehogs, with cells false-coloured pink and hedgehogs false-coloured green. The image captures the cells when they are degranulating. b Tight interfaces between RBL cells and nanoneedle hedgehogs. c The cell membrane and extracellular matrix of RBL cells can rip nanoneedles out of the hierarchical microcrystal, demonstrating the strength of the cell/nanocrystals interaction. d RBL cell culture interrupted at different intervals (hours shown in image upper right corners), showing the progression of cell attachment, proliferation and morphology over time. Scale bars = 5 µm