May 15 (UPI) -- Researchers at the University of California, San Diego have created a nano-sized optical fiber capable of listening to and sensing the forces created by cells.
The device -- a sort of stethoscope for individual cells -- measures just a few hundred nanometers across, 100-times thinner than a strand of human hair.
The fiber is 10 times more sensitive than an atomic force microscope. When scientists placed the device in a solution containing a small sample of common gut microbes, the fiber was able to detect forces ten trillion times smaller than a single newton. When exposed to cultures of mice heart cells, the fiber was able to detect sounds as faint as negative 30 decibels.
"This work could open up new doors to track small interactions and changes that couldn't be tracked before," lead researcher Donald Sirbuly, a professor of nanoengineering at UC San Diego, said in a news release.
Sirbuly says the device could be used to study the biomechanics of cells and detect potentially harmful transformations. The fiber could listen for signs of a viral attack or cancerous growth.
The device features a tiny strand of tin dioxide. The fiber is coated in a thin layer of polyethylene glycol, a type of polymer. The coating is dusted with gold nanoparticles.
Scientists send a beam of light down the nano fiber and measure how forces emitted by the studied medium -- whether cell culture and bacterial solutions -- affect the light. The polymer's sensitivity to surrounding forces is key to the device's performance. Researchers can use a thicker, harder coating to measure larger forces, or a thinner, squishier polymer to measure smaller forces.
"We're not just able to pick up these small forces and sounds, we can quantify them using this device," Sirbuly said. "This is a new tool for high resolution nanomechanical probing."
Researchers described the novel nano fiber in the journal Nature Photonics.