This cube detects the fluorescence from two calcium indicators and GCaMP isosbestic point. The separation of functional and isosbestic fluorescence signals of GCaMP is possible with modulated light sources. E1 and E2 stand for excitation at the cube's schematic, IE for isosbestic excitation, F1 and F2 for respective fluorescence windows, and S for the sample port. Compared to Fluorescence Mini Cubes with only FC connectors on all ports, the ones with integrated photodetectors provide a 100% better signal-to-noise ratio (30% signal increase and a 40% noise reduction). Moreover, in the latest generation of Mini Cubes, LEDs and LED drivers are integrated as well to reduce the number of connections and the system’s overall footprint. In his generation, it is also possible to replace the excitation filter (to adjust the isosbestic excitation from 405 nm to 410 nm for instance) and decrease the excitation power by adding attenuating filters (for low power photometry).
