A 340/380 nm light emitting diode illuminator for Fura-2 AM ratiometric Ca2+ imaging of live cells with better than 5 nM precision

Cytosolic Ca2+ plays an integral role in cells and the study of its dynamics can reveal much about biological processes [1]. Fura-2 can provide quantitative data on cytosolic Ca2+ changes by exciting at 340 nm and 380 nm and taking the ratio of the emission at both wavelengths [2]. Traditionally for this type of imaging an arc lamp had to be used for illumination as LEDs of the appropriate wavelengths were not available [3]. LEDs hold advantages over arc lamps by exhibiting high amplitude stability and the ability to rapidly switch between wavelengths. We aimed to test a new 340/380 nm LED system for use in ratiometric Fura-2 AM Ca2+ imaging and present results using tsA-201 cells and hippocampal neurons.