Two-photon laser scanning microscopy (2PLSM; a form of non-linear laser scanning microscopy) is a fluorescence imaging technique that allows fast and minimally invasive imaging of living tissue to a depth of one millimeter at sub-micrometer lateral resolution.
Compared to confocal microscopy, 2PLSM offers the advantages of deeper tissue penetration, less photo damage outside the focal region, inherent optical slicing and less chromatic aberration.
2PLSM can be used to image the structure and function of brain cells in living research animals (most commonly mice and rats). For example, the technology enables imaging of calcium signaling at the synaptic level, even on the millisecond time scale, cerebral blood flow (after intravascular injection of fluorescent dye), brain fluid dynamics (after injection of fluorescent tracer in the cerebrospinal fluid), and brain metabolism (NADH fluorescence).
We have three models of “Ultima IV” two-photon laser scanning microscopy stations one model of “MOM” two-photon laser scanning microscopy station.
We have three models of “Ultima IV” 2PLSM stations, produced by Prairie Technologies, Inc., Middleton, WI (a Bruker Corporation).
The setups allow imaging in vivo – even on the behaving animal, active on, e. g. a track ball – and include high quality objectives, image scanners, rapid scanners (AOD or resonant galvanometric), and independently controllable scanners for chemical activation purposes.
The system include up to four detectors of which at least three highly efficient (40% QE in the visible wavelength range) GaAsP PMT tube detectors (cooled by Peltier elements). The laser sources are group wave dispersion compensated ultra-fast laser units emitting wave lengths in the range 680nm-1080nm/1300nm.
The setups also include a state of the art data acquisition software (uses “Prairie View”), which, in coordination with the high-end user electronics, also allows for time coordinated image scanning, chemical activation and control of external processes.
- The microscope system
- The laser sources:
- The GaAsP detectors
- The objectives
We have one model of “MOM” 2PLSM station produced by Sutter Instruments Corp., Novato, CA.
This setup is optimized for in vivo laser scanning microscopy on the behaving animal. It is equipped with a track ball. A high quality objective is provided. The light detectors are GaAsP PMT tubes (not cooled). The laser is a GVD compensated ultra fast Ti:Sap laser emitting light in the wavelength range 690nm-1060nm at typically 70fsec pulse width.
More details about the microscope system and software:
Photo: Knut Sindre Åbjørsbråten, Institutt for medisinske basalfag, UiO.