This is a microscopic scale that can measure the mass of a single molecule. The scale was manufactured with the same semiconductor fabrication technology used to make computer chips. From Smithsonian:
As described in a paper published in the journal Nature Nanotechnology, the tiny apparatus is built around a bridge-like structure that vibrates at a specific frequency based on the mass of the molecule on top of it. By precisely tracking the vibrating frequency of the bridge, they can determine the exact mass of the molecule.