Correction to: Nature Biomedical Engineering https://doi.org/10.1038/s41551-018-0193-2, published online 6 February 2018.

In the version of this Article originally published, in Fig. 1a, all cells in the top schematic were missing, and in the bottom-left schematic showing multiple pattern shapes, two cells were missing in the bottom-right corner. This figure has now been updated in all versions of the Article.

Fig. 1a: Original and corrected.
figure 1

The corrected version includes the cells.