In situ fiber‐optical monitoring of cytosolic calcium in tissue explant cultures
We present a fluorescence‐lifetime based method for monitoring cell and tissue activity in situ, during cell culturing and in the presence of a strong autofluorescence background. The miniature fiber‐optic probes are easily incorporated in the tight space of a cell culture chamber or in an endoscope. As a first application we monitored the cytosolic calcium levels in porcine tracheal explant cultures using the Calcium Green‐5N (CG5N) indicator. Despite the simplicity of the optical setup we are able to detect changes of calcium concentration as small as 2.5 nM, with a monitoring time resolution of less than 1 s. (© 2013 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)