Olympus has introduced the IX81-ZDC2 Zero Drift microscope system - a motorised inverted microscope with an integrated autofocus solution for investigators carrying out time-lapse experiments.
The IX81-ZDC2's next-generation autofocus system is designed to operate continuously so that it maintains focus even when the events being observed happen very quickly and experiments occur over a short timescale.
In addition, the system can be set to operate in a discrete, one-shot mode to facilitate applications that require maintaining multiple focus positions, such as experiments involving multi-well imaging.
The system is optimised for use with total internal reflectance fluorescence (TIRF) and other advanced applications.
The ZDC2 Zero Drift system uses a Class 1 785nm laser diode to locate either the water/glass interface (for oil- or water-immersion objectives) or the air/glass interface (for non-immersion lenses).
Samples can be mounted on coverslips, multi-well tissue culture plates, glass-bottom culture dishes or other glass substrates.
Working in tandem with Metamorph for Olympus software, ZDC2 Zero Drift uses an intermediate lens to focus to the desired z-position (depth) in the sample, automatically maintaining focus for seconds, hours, days or weeks.
Using its automated continuous mode, users can retain precise focus even after reagents are added.
The IX81-ZDC2 Zero Drift is said to provide sharp, bright images under time-lapse conditions.
It can be used with a broad range of objectives including two key high-transmission Olympus TIRF lenses: the APON 60x 1.49 NA and the UAPON 100x 1.49 NA objectives.
ZDC2 Zero Drift is also suitable for keeping focus during multi-modal calcium experiments that employ both TIRF and Fura-2.
In conjunction with the Olympus cell TIRF illuminator, the system allows simultaneous, high-speed multi-angle TIRF imaging.
The autofocus system is integrated into the Olympus IX81 microscope stand, which is claimed to be rigid, stable and reliable.
The small footprint of the IX81 houses a very efficient light path, and ZDC2 Zero Drift does not require the use of a second control pad or other accessories that can clutter the lab bench.
Olympus research objectives are designed for multi-wavelength time-lapse imaging, and have chromatic correction ranging from 330nm up to 1,100nm, depending on the objective.
Olympus objectives also are lighter and more compact than others, so there is less mechanical stress on the microscope as it cycles through numerous small z-step changes over an extended duration.
The ZDC2 Zero Drift system operates by taking advantage of the specimen-coverslip relationship.
While the distance between the objective and coverslip can be affected by temperature, gravity, immersion media viscosity and other factors, the distance between the coverslip and an attached cell is much more stable.
ZDC2 Zero Drift locates the specimen-coverslip interface reliably and is able to return to the defined focus position with accuracy, even if the objective-to-coverslip distance changes.
Further, the system uses an autofocus routine that is faster than conventional software-based algorithms and is unaffected by changes in morphology, contrast or fluorescence intensity of the cell.
The laser can be turned off during periods when image acquisition is not occurring.
In addition to TIRF, the autofocus system works well with high-throughput screening and other high-accuracy time-lapse studies of living cells in stage incubation systems.
