Oct. 26 (UPI) -- Scientists in Switzerland have developed a scale capable of weighing a single living cell. The device can even calculate changes in a cell's weight in real time -- with precision to milliseconds and trillionths of a gram.
The scale was designed by scientists at the Swiss Federal Institute of Technology in Zurich, or ETH Zurich. The device's arm features a transparent silicon cantilever. The wafer-thin plate is coated with a film of collagen or fibronectin. To weigh a cell, scientists lower the cantilever in a cell culture chamber where it presses against the cell and picks it up.
"The cell hangs on the underside of a tiny cantilever for the measurements," doctoral student Gotthold Fläschner, who helped design the scale, said in a news release.
At the opposite end of the device's arm is a pulsing blue laser, which causes the nanoscale cantilever to oscillate. A second infrared laser measures the oscillation before and after the cell is affixed to the plate.
"The cell's mass can be calculated from the difference between the two oscillations," said researcher David Martínez-Martín, who invented the device.
The technology feeds real-time measurements to a computer screen. A cell's mass fluctuations can be tracked for several hours or even days.
The scale can be installed on the object plate of a high-performance fluorescence microscope, allowing scientists to observe biochemical process inside the cell while monitoring changes in the cell's weight.
Early tests using the scale has already begun to offer insights.
"We established that the weight of living cells fluctuates continuously by about one to four percent as they regulate their total weight," said Martínez-Martín.
The fluctuation in weight only ceases after the cell dies.
"We're seeing things that nobody else has yet observed," Fläschner said.
Researchers described their new technology in a paper published this week in the journal Nature.
Scientists expect the new technology to be used to study a variety of cellular processes. The device could be used to analyze a pathological mechanisms inside a diseased cell or observe the effects of a new drug.
"A cell's mass is a very good indicator of its physiology," said Martínez-Martín.
The patented scale -- which could also be used by material scientists to measure nanoparticles -- will soon by manufactured by Swiss company Nanosurf AG.