Light microscopic techniques date back to the end of the 17th century when Anthonie van
Leeuwenhoek built an optical device with a series of self-ground lenses. These techniques
were instrumental in discovering and elucidating the cellular organization and structure of
many organisms. It took until the last decades, to develop fluorescent probes with specific
biological or chemical function, before physiologic processes could be monitored. To this
end, molecules were designed to either become membrane potential or ion (Ca2+, H+,...) …