ZEISS Workshop on detection concepts in confocal microscopy
Dr. Uros Krzic, Dr. Richard Ankerhold / Carl Zeiss Microscopy GmbH

Since confocal scanning microscopy was invented it has developed into an indispensable and widely spread tool for microscopic imaging in biomedical research. While confocal microscopy is nowadays a matured technology available off-the-shelf from several microscope producers, it is still subject to rapid development. Almost every year we witness new improvements that push the limits in terms of speed, sensitivity, resolution, functionality and versatility.
The development has been in recent years largely driven by advances in detector technologies. Most notably, introduction of gallium arsenide phosphide (GaAsP) photocathode led to a new generation of detectors with an unmatched sensitivity. The combination of PMT (photomultiplier tube) and APD (avalanche photodiode) technologies gave rise to a photodetector (hybrid photodetector), that is also well suited for time-resolved measurements. The availability of multi-detector PMT arrays opened a myriad of new possibilities in hyper-dimensional imaging. The latest development is the Airyscan detector. This novel detection technique exploits the design of a sensitive GaAsP detector array to scan over the Airy disk (hence the name). It replaces the pinhole as the core component of a conventional confocal microscope by imaging the fluorescent spot simultaneously onto a multitude of detectors. Thus, the intrinsic drawback of classical confocal imaging sacrificing fluorescence light for sectioning and resolution could be eliminated. The reassignment of the detected fluorescence at each detector subunit produces images with boosted signal-to-noise and a resolution improvement. In other words, an experimenter is able to see more detail with less light, using the same sample preparation procedures, dyes and acquisition conditions. Airyscan is a very flexible and powerful detector concept.
In the first part of the workshop we will present an overview of currently used confocal detectors and detection concepts, and their strengths and weaknesses in biomedical imaging. The second part of the workshop will be dedicated to an open discussion on future directions in confocal detection concepts, with special focus on synergies between advanced detectors and signal processing. There has been a high innovation rate in software and processing algorithms in microscopy that can be applied for instance in conjunction with particular illumination and detection schemes. What is the future potential of these approaches in biomedical imaging? How can we benefit from the best of both worlds – modern detector hardware blended with clever digital processing?

European Molecular Biology Laboratory (EMBL)
Advanced Training Center
Meyerhofstraße 1
69117 Heidelberg
Germany