Multispot live-image autofocusing for high-throughput microscopy of fluorescently stained bacteria

Authors

  • M. Zeder,

    1. Department of Limnology, Institute of Plant Biology, University of Zürich, Kilchberg CH-8802, Switzerland
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  • J. Pernthaler

    Corresponding author
    1. Department of Limnology, Institute of Plant Biology, University of Zürich, Kilchberg CH-8802, Switzerland
    • Department of Limnology, Institute of Plant Biology, University of Zürich, Seestrasse 187, Kilchberg CH-8802, Switzerland
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Abstract

Screening by automated high-throughput microscopy has become a valuable research tool. An essential component of such systems is the autonomous acquisition of focused images. Here we describe the implementation of a high-precision autofocus routine for imaging of fluorescently stained bacteria on a commercially available microscope. We integrated various concepts and strategies that together substantially enhance the performance of autonomous image acquisition. These are (i) nested focusing in bright-field and fluorescence illumination, (ii) autofocusing by continuous life-image acquisition during movement in z-direction rather than at distinct z-positions, (iii) assessment of the quality and topology of a field of view (FOV) by multispot focus measurements, and (iv) acquisition of z-stacks and application of an extended depth of field algorithm to compensate for FOV unevenness. The freely provided program and documented source code allow ready adaptation of the here presented approach to various platforms and scientific questions. © 2009 International Society for Advancement of Cytometry

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