Yes, that's live human cells. And before you say it: No, this actually has nothing to do with 3D printing.
Yep – the team, from Clemson University in South Carolina, did it all with a basic inkjet printer.
Here's what they did: researchers took the printer's standard ink cartridges, removed the ink and replaced it with a special cell-packed solution.
The printer – a HP Deskjet 500 apparently – was modified by removing the paper feed mechanism and adding a 'stage' from which to feed the slides with the solution. The cells were printed straight onto the slides.
The process creates cells that have temporary holes in their walls that allow molecules to be injected. This enabled researchers to analyse the workings of the cells.
"We are actually interested in the cell mechanics of compressed cells. This method allows us to push on the cells and watch the response easily," said Dr Delphine Dean, the author of the study.
"We are interested in cardiovascular cells, and how they respond to mechanical force."
Impressive stuff, huh?