Researchers at ETH Zurich University have come up with a scale for weighing individual cells. A cell can be weighed in a cell culture chamber, where a tiny weighing arm coated with collagen can be lowered to the floor of the chamber to pick up the cell. On each end of the weighing arm is an infrared laser; a blue laser from one end of the arm causes the cell to oscillate slightly, while the other infrared laser measures the oscillation. Then, the difference between the oscillations within and without the cell is used to calculate the cell’s mass.

What makes this invention valuable is that the internal process of the cell can be monitored simultaneously as the measurements are taken, since the measuring apparatus is placed on a fluorescence microscope. Therefore, the cell scale can be used to track the weight of a cell during various stages of the cell cycle or to test the effects of a virus infection on a cell’s weight. The cell scale has already been patented and is now on its way to production by the Swiss company Nanosurf AG.