THORNWOOD, N.Y., May 25, 2010 — For wide-field fluorescence microscopy applications, Carl Zeiss MicroImaging Inc. has incorporated into its Colibri illumination system high-intensity LEDs in a variety of colors that match the excitation bandwidth of many commonly used fluorescent dyes and proteins. The modular light source system uses specific wavelength windows and up to four LEDs, each individually and instantly controlled by electrical current without mechanical switching devices like filter wheels or shutters. LEDs of different colors can be used in combination, giving users the option of seeing multiple fluorochromes simultaneously or rapidly capturing sequential images of each fluorochrome. The beam paths from each of the four LED modules are steered into the microscope with a series of beam combiners, and 10 LED modules are currently available, from UV to dark red. Available are 365-, 380-, 400-, 455-, 470-, 505-, 530-, 590-, 615- and 625-nm versions. The modules can be easily exchanged by the user depending upon the experimental design. The intensity of each module can be adjusted independently, precisely and reproducibly in percentage steps, so that for every fluorescent dye, the output emitted is precisely that which is needed to achieve the best possible compromise between the required excitation intensity and maximum sample protection. Equidistant multichannel images can be realized in time-lapse-series. Instead of adapting the integration times of the camera to the illumination intensity, LED technology makes it possible to set the illumination intensity for the required integration time. The LED illumination intensity is also highly stable over time, making quantitative analysis easier and more reliable. The company has integrated Colibri with its AxioVision software imaging platform, resulting in extremely fast switching times of 300 µs, with precise control of the illumination intensity to protect the sample. For applications requiring higher illumination intensity, or for applications requiring excitation wavelengths not currently supported by existing LED technology, the company offers a combination system that pairs a Colibri with an externally coupled metal halide white-light source.