Highly read on www.pnas.org in August

Small molecules can be used for high-resolution fluorescence imaging of membrane-bound organelles in living cells.

A team led by Guo-Qiang Bi at the University of Science and Technology of China in Hefei and Xiaowei Zhuang at Harvard University in Cambridge, Massachusetts, developed a fluorescence-imaging method that uses common membrane probes. The researchers showed that the fluorescence of eight such probes can be switched on and off in living cells in normal culture medium, enabling high-resolution imaging. Using the probes, the researchers were able to obtain images of key organelles, including the power-generating mitochondria, with a spatial resolution of 30–60 nanometres and a temporal resolution of 1–2 seconds. This allowed them to capture previously unseen details about the dynamic membranes of the organelles, such as structures involved in the fusing of mitochondria.

Proc. Natl Acad. Sci. USA 109, 13978–13983 (2012)