Zeiss says it has overcome the challenge of imaging deep inside living tissues with the launch of the LSM 5 MP multiphoton laser scanning microscope
The LSM 5 MP uses longer-wavelength, femtosecond lasers to create and detect fluorescence signals at a depth of up to 500 microns, illuminating cellular structures in great detail while eliminating phototoxic cellular damage caused by high intensity light.
The instrument is based on the recently launched Axio Observer inverted research microscope platform and takes advantage of its sophisticated optical features.
Highly efficient coatings on the optics ensure minimal power losses of the directly coupled femtosecond lasers while advanced filter technology guarantees efficient suppression of stray and excitation light and extremely sensitive detection of fluorescent signals.
New optical standards are set by the W Plan-Apochromat objective lens, which boasts 20x magnification at a numerical aperture of 1.0 and a working distance of 2mm.
It is said to be ideally suited to multiphoton electrophysiology experimentation, allowing larger areas to be imaged with unsurpassed resolution and brilliance.
The specially designed objective lenses feature optical correction in the near infra red (NIR) 700-1100nm spectral range to reduce absorption and scatter.
This allows the NIR laser to penetrate tissue to greater depths working in ultrashort pulses of up to 170kW at a frequency of 76 to 90MHz.
Unlike conventional confocal microscopes that quickly lose their capacity to resolve fluorescent structures in thicker specimens due to the absorption and scattering of both the excitation and emitted light, the multiphoton LSM 5 MP restricts fluorescence excitation to the focal spot.
The laser beam only excites fluorescence if at least two photons are absorbed by a fluorochrome molecule within less than a femtosecond (10-15 seconds) and the whole of the emitted light signal can be used for imaging.
The LSM 5 MP is ideally suited to the study of live biological tissue, including intact animals, where its ability to image fluorescence-labelled cellular structures at depths up to 500 microns without damage is a key advantage.
