Novel Microscopy Technique Tracks Moving Microbes

The technique allows for the following of an unprecedented 24,000 rapidly moving cells over wide fields of view and through large sample volumes, recording each cell's path for as long as 20 seconds.

Scientists at the University of California (UCLA; Los Angeles, CA, USA) used offset beams of red and blue light to create holographic information that, when processed using sophisticated software, accurately reveal the paths of objects moving under a microscope. The y tracked several cohorts of more than 1,500 human male gamete cells over a relatively wide field of view of more than 17 square millimeters and large sample volume of up to 17 cubic millimeters over several seconds.


The technique, along with a novel software algorithm that the team developed to process observational data, revealed previously unknown statistical pathways for the cells. The scientists found that human male gamete cells travel in a series of twists and turns along a constantly changing path that occasionally follows a tight helix, a spiral that, 90% of the time, is in a clockwise or right-handed direction. Because only four to five percent of the cells in a given sample traveled in a helical path at any given time, microscopists would not have been able to observe the rare behavior without the new high-throughput microscopy technique.

The authors report reports observations of 24,000 cells over the duration of this study. Such a large number of observations provide a statistically significant dataset and a useful methodology for potentially studying a range of subjects, from the impact of pharmaceuticals and other substances on large numbers of cells, in real time, to fertility treatments and drug development. The same approach may also enable scientists to study quick-moving, single-celled microorganisms. The new lens-free holographic imaging technique could potentially reveal unknown elements of protozoan behavior and allow real-time testing of novel drug treatments to combat some of the most pathogenic forms of those organisms. The study was published on September 17, 2012, in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).

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