The Definite Focus system from Carl Zeiss (Thornwood, NY) works with the company's Axio Observer.Z1 to facilitate research of cell cultures in many biomedical applications (cell biology, pharmacology, molecular genetics, developmental biology, neuroscience, and more), and in basic research.
The system is designed for fluorescence applications and time-lapse experiments under live cell conditions. It effectively counteracts drifting in the Z-direction, so that the microscopic image always remains in focus. Furthermore, it promises to reduce preparation and waiting times in time-lapse experiments.
Since the introduction of the Axiovert 200 in 2000 and its successor, the Axio Observer, in 2006, hundreds of customers have successfully used these systems for long term time lapse imaging over periods as long as 72 hours. But increasing interest of integration of temperature impact on cell viability as part of the experiment put new demands on the ability of the imaging system to quickly compensate for temperature changes. Definite Focus was designed to solve this with its full integration into the workflow of the Axio Vision imaging workflow.
Definite Focus is coupled directly to the nosepiece carrier and directs infrared light of wavelength 835 nm into the beam path of the Axio Observer.Z1 inverted research microscope. To measure the distance between the objective and the specimen, a grid is projected onto the bottom of the culture vessel, and the reflection of this projection is analyzed. Possible deviations from the nominal value are determined and corrected quickly and very precisely via the Z-drive of the Axio Observer in the case of drifting. Even with high-magnification objectives, the system can be used without limitations for all contrasting techniques.
Definite Focus promises increased experimental reliability. Furthermore, incubation conditions can now be better structured according to needs, the company says. With stage incubation using the PM S1 incubator, for example, the user can quickly change the temperature as required during the experiment. Typical examples of dynamic temperature experiments include the analysis of protein folding mutants or heatshock experiments. Until now, performance of the relevant experiments had not been possible due to pronounced focus fluctuations.
Definite Focus can be operated directly via the TFT touchscreen display of Axio Observer.Z1. It offers additional functions such as the storage of two nominal values and the possibility of using the system as a "focus finder" after replacement of the culture vessel. It is fully compatible with Carl Zeiss's AxioVision and LSM software, and supports all Axio Observer options such as TIRF, LSM or multiphoton microscopy. It works with standard culture vessels, including multiwell dishes with glass or plastic bottoms. The supplied hardware comprises a sensor module on the nosepiece carrier, a beam combiner below the nosepiece and a Definite Focus controller.
Carl Zeiss Microimaging