Pictured is a fluorescently labeled endothelial cell monolayer, pseudocolorized in blue/green, and imaged using spectral confocal microscopy. One cell has been selectively perforated via ultrasound-induced microbubble cavitation (simultaneously captured by ultrafast imaging, top panels), allowing the entrance of a model therapeutic (orange).
At University of Pittsburgh and University of Pittsburgh Medical Center researchers have devised a radically new way of opening carefully targeted living cells to allow various medications to enter. Reported on in the latest issue of Proceedings of the National Academy of Sciences, the scientists describe how microbubbles filled with genes can be excited with ultrasound to shove themselves into the interior of cells. Such microbubbles have been developed already, but while they’re immeasurably safer than viruses they’ve had a problem of penetrating cells.
While the team suspected that this is possible, they had to figure out what kind of stress needs to be generated in the microbubbles for them to have the right excitation to get the cells to open up. To do this, they built a camera that can film microbubbles under ultrasound at 25 million frames per second. The investigators were able to determine what settings and methods lead to optimal results for specific cell targets.
Thinking of the future, in order to introduce the technology into clinical use, the researchers believe that there will be a lot of figuring out necessary to tune and optimize sonoporation for specific applications.
Here’s a sample microscopy video of a microbubble filmed at 25 million fps:
