Nano-sized optical fibers detecting femtonewton-scale forces produced by swimming bacteria

Researchers at the University of California San Diego have created a miniature device so sensitive it can feel the forces generated by swimming bacteria and hear the beating of heart muscle cells. The device is a nano-scale optical fiber that is about 100 times thinner than a human hair, and is made from an extremely thin fiber of tin dioxide encrusted with a thin layer of polyethylene glycol, and gold nanoparticles.

With more than 10 times more sensitive than the atomic force microscope (AFM), this newly developed device can detect forces down to 160 femtonewtons — about ten trillion times smaller than a newton. And such sensitivity allows the device to sense the forces produced by live Helicobacter pylori bacteria – swimming bacteria found in the gut – in the solution, as well as detect sounds of beating heart muscle cells down to -30 decibels, which is one thousand times below the limit of human hearing.

Source/Reference: UCSD | Nanofibre optic force transducers with sub-piconewton resolution via near-field plasmon–dielectric interactions. Nature Photonics, 2017. DOI: 10.1038/nphoton.2017.74