Researchers have designed process that uses ultrasound to modify the behavior of cancer-fighting T cells by increasing their cell permeability. They targeted freshly isolated human immune cells with tightly focused ultrasound beams and clinically approved contrast agent microbubbles. When hit with the ultrasound, the bubbles vibrate at extremely high frequency, acting as a push-pull on the walls of the T cell's membranes. This can mimic the T cell's natural response to the presence of an antigen. The T cell then begins to secrete vital signalling molecules that would otherwise be restricted by the tumor's hostile microenvironment. The process does not damage the cell itself.