SCIENCE - Weighing nanoparticles at the attogram scale

MIT engineers have devised a way to measure the mass of particles with a resolution better than an attogram—one millionth of a trillionth of a gram. Weighing these tiny particles, including both synthetic nanoparticles and biological components of cells, could help researchers better understand their composition and function ...

http://phys.org/news/2014-01-nanoparticles-attogram-scale.htm