Fig. 5

SEM imaging of human embryonic kidney (HEK) cells cultured with quinacridone nanohedgehogs. a Close and highly conformal interfaces form after a few hours in culture. b Engulfment-like events are observable in the case of HEK cells, here a cell is imaged in the course of an endocytosis event with a nanodagger hedgehog. c HEK cells do not grow on evaporated quinacridone thin-films. Here cells are cultured on substrates with hedgehogs where the entire surface, including hedgehogs, is coated with a uniform sublimated quinacridone thin film, thus demonstrating that the nanostructure and not chemical nature of the substrate is critical for cell adhesion. d Interface contact between HEK cells and hedgehogs increases over cell culture time, and morphology transitions from rounded cells with a few attachment points to cells showing extensive spreading on the hedgehog structures. Scale bars = 2.5 µm