A549 cell culture results for spheroid morphology after 72 h. (A) Spheroid formation in the novel design with no bubble present. (B) Spheroid formation in the standard design with no bubble present. (C) Calcein AM/Propidium Iodide staining of a spheroid from the novel design with a bubble present. (D) Spheroid formation in the novel design with a bubble present. (E) Spheroid formation in the standard design with a bubble present. (F) Calcein AM/Propidium Iodide staining of a spheroid from the standard design with a bubble present. (G) Combined quantified results for spheroid areas for each of the above conditions taken as the average of medians, for details, see text. (H) Combined quantified results for spheroid circularity taken as an average of averages of independent triplicate data, for details, see text. Scale bars for (A, B, D, E) are 200 μm, scale bars for C and F are 100 μm. *Significant at p < 0.05. NS, not significant. Color images are available online.