Nikon A1 Si Single Photon Confocal Microscope

The Biology Department Nikon A1Si LSCM was installed in 2009. It offers many features for acquisition and analysis of high-quality fluorescent and Differential Interference Contrast images. The A1Si features 4 Melles-Griot lasers ranging from 408 nm (near blue) to 640 nm (far red) that can either be imaged by separately dedicated photomultipliers to allow up to 5 channel imaging (4 fluorescent + 1 transmitted), or the lasers can instead be directed to a 32 channel spectral detector for analysis at 2.5, 6, or 10 nm intervals allowing spectral analysis of a sample over a wavelength range of up to 320 nm. In addition, the spectral detector output can be binned into up to 4 channels to allow fine-tuning of emission output for unusual fluorophores (Virtual Filtering). Regions of Interest (ROI’s) can be chosen from the full 32-channel output and unmixed into separate channels in real time so that even objects with very close emission maxima can be cleanly separated from one another (Spectral Unmixing). The 408 nm laser allows direct visualization of DAPI- stained samples for quick and accurate analysis of cell nuclear material, and can be used to bleach or activate ROI’s for FRAP or photoactivation analysis. The rapid and accurate Z motor allows for rapid 3D acquisition in the Z plane and can easily be coupled to a time-lapse macro for 4D imaging. In addition, FRET, FLIP and colocalization studies can be performed. Finally, Nikon’s low-incident angle dichroics and hexagonal pinhole combine to allow much lower laser powers to be used for sensitive live imaging.