According to Official Guinness Records,
A nanobalance, made by groups from the University of Barcelona, Spain, and EPFL Microsystems Laboratory, Switzerland, is the first electronic sensor capable of measuring the pressure of vapour and gas flows as low as 10 picometres per second.
This type of measurement is used in the construction of integrated circuit electronics such as computer chips, as well as detecting single organic cells and other bio-materials too small for conventional quartz-based micro-balances. The balance detects any mass falling on it by a change in resonance frequency of a lever beam less than 1 micrometre wide.
For a complete list of 2009 records, please visit 2009 Guinness Records in Spain.