In microscopy and analytical instrumentation, a researcher or clinician may need to excite several fluorophores in a sample in order to generate a useful fluorescence map of the cell or tissue of interest. This typically would include a nuclear marker such as DAPI, a green-emitting fluorophore such as FITC or GFP, and a red-emitting fluorophore such as mCherry, TRITC, or Texas Red. These red-emitting dyes can be efficiently excited using an arc lamp with a strong peak in the 550 nm region and another at 580 nm. When technology in microscope light sources originally moved to light-emitting diodes (LEDs) in the early 2000s, fluorescence work in the green gap (540 to 590 nm) excitation range was a challenge with no solution. This article explains how technology has adapted to provide LEDs that match the excitation of fluorophores typically used in multiplex fluorescence imaging.
