Stanford Turns Ultrasound Into Light Inside the Body
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- Stanford researchers led by Guosong Hong published a Nature Materials paper showing that processed ceramic nanoparticles with a biocompatible coating can be injected into the bloodstream and convert focused ultrasound waves into light at precise body locations.
- Guosong Hong, an assistant professor of materials science and engineering at Stanford and senior author on the paper, said the technology can produce light "in the brain, in the gut, in the spinal cord, in the muscle—virtually anywhere—without needing a physical implant."
- Researchers demonstrated the approach on mice using a small ultrasound-producing hat to generate light in specific brain regions, successfully stimulating neurons and causing the mice to turn left or right depending on which area was activated.
- The nanoparticles emit blue light at 490 nanometers, a wavelength useful for exciting neurons and photodynamic cancer therapy, while the team is also experimenting with ultraviolet-emitting materials that could kill bacteria and viruses.
- Hong is collaborating with Stanford neurobiology and bioengineering professor Michael Lin to pair the ultrasound-light system with a light-activated gene-editing platform, potentially enabling localized, ultrasound-controlled genetic modifications.
- A key safety concern is that the ceramic nanoparticles do not break down quickly and have the potential to accumulate in the liver, leading researchers to pursue biodegradable biological replacements before any human clinical applications.
Why it matters: Current light-based treatments for deep tissue require cutting or inserting optical fibers. This ultrasound-driven system eliminates that invasiveness for potential brain, cancer, and gene-editing applications. The bottleneck: the ceramic nanoparticles do not break down quickly, and researchers flagged liver accumulation as a concern, so they are now seeking biodegradable replacements before any human use.
