The new device uses a nano-sized cantilever to detect motion. A cantilever is essentially a beam that is anchored only at one end, with the other end bearing a load. The idea comes from the technology behind an existing microscope, the atomic force microscope.
This powerful microscope uses a cantilever to produce pictures of the atoms on a surface. In the new device, a bacterium attaches to the cantilever. If the bacterium is alive, it inevitably moves in some way. That motion also moves the much smaller and sensitive cantilever and it is captured by the readout laser as series of vibrations. The signal is taken as a sign of life.
The team successfully tested their novel system with isolated bacteria, yeast, mouse and human cells. The scientists envision a large array of cantilever sensors used in future space exploration probes like the Mars rover. The more immediate applications of the cantilever system are in drug development, they added. The study was published in the journal Proceedings of the National Academy of Sciences (PNAS).