Technologies

Salk scientists have developed a new way to selectively activate brain, heart, muscle and other cells using ultrasonic waves in order to better understand their function. The new technique, dubbed sonogenetics, has similarities to the popular field of optogenetics, which uses light to activate cells in a selective manner, however unlike light, which scatters in tissue, low-frequency ultrasound can travel through the body without any scattering and loss of signal.

Salk scientists identified a pore-forming subunit of a mechanotransduction channel, TRP-4, that is sensitive to low-pressure ultrasound. C. elegans express TRP-4 and normally use channels to sense when their bodies are stretching. When the worms stretch, the channels open and allow calcium to flow through. Salk scientists found that neuron-specific misexpression of TRP-4, sensitizes neurons to ultrasound stimulus, resulting in behavioral outputs.

Sonogenetics uses ectopic expression of TRP-4 and low-intensity ultrasound waves, the same type of waves used in medical sonograms, to selectively activate cells. As these waves can travel deep into tissue, it avoids the need to used surgical technologies such as imbedding the fiber optic cables used to deliver light to these regions. Avoiding such invasive surgery makes sonogenetics a particularly attractive approach especially when it comes to adapting the technology for human therapeutic use.