Zeiss has developed a light sheet microscope for 3D observations of biological samples over very long periods of time. The microscope incorporates a MEMS scanner developed by the Fraunhofer Institute for Photonic Microsystems IPMS.
The light sheet fluorescence microscope system, Lightsheet Z.1, gives researchers the opportunity to observe dynamic processes in large living organisms. Compared to former methods of fluorescence microscopy such as confocal microscopy, this system is characterised by a lower light load on the specimens, opening up new possibilities for gentle, long-term examinations of living organisms in 3D.
Light sheet fluorescence microscopy (LSFM) allows only the relevant volume and not the entire specimen to be illuminated for a section of the fluorescence-marked tissue by a very thin, expanded laser beam, the so-called light sheet. This means that the fluorescent dye is only locally excited to emit light. A projection lens that points vertically on the light sheet with a downstream camera efficiently records the emitted light.
For the first time, according to the company, specimens can now be recorded under natural, physiological conditions and the development of entire organisms tracked three-dimensionally for many days.
A resonant microscanner developed by the Fraunhofer IPMS is used to perfect the imaging quality and eliminate unwanted artefacts such as shadowing caused by opaque components of the specimen in the light sheet. The pivot scanner (or MEMS scanner) has a reflecting plate with a diameter of 1.2mm and a mechanical scanning amplitude that can be adapted dynamically to the desired lens magnification in the range from 0.9 to 6°, and will be operated near its mechanical resonance at 23kHz.