Biologists have been making movies of mammalian cells almost as long as they’ve been able to culture them. In the 1950s, these time lapse “cinemicrographs” showed how the cells’ morphology changed during mitosis or early embryonic development. Because the available microscopy stains were generally lethal, though, researchers could only track changes that were visible with phase contrast or other stain-free techniques.

Fifty years later, time lapse imaging is enjoying a tremendous renaissance. The availability of fluorescent chimeric proteins and other live-cell labeling techniques, combined with inexpensive but highly sensitive digital image acquisition and analysis, has made live cell studies a staple of modern cell biology.

click to enlarge The VivaView integrated microscope and incubator is designed especially for live-cell imaging. (Source: Olympus America)

Unfortunately, the technology’s rapid development has often meant that scientists had to build their own equipment to enjoy the latest features. From cobbling together microscope stage incubators to writing custom software for analyzing massive sets of images, time lapse microscopy has been a field for the technically inclined. That’s become even more true as the experiments have gotten more complicated.

“People ... don’t want to do just the 20-minute or the two-hour experiment, they really want to watch their cells grow and differentiate over two, three, four, five days,” says Stuart Shand, associate product manager for Olympus America in Center Valley, Pa. Such extended experiments require not only precision microscopy, but tight control of the incubation conditions on the microscope stage.

In response, manufacturers have been developing a new generation of user-friendly tools built especially for live-cell imaging. The competition of multiple vendors, and the availability of different systems specialized for different types of work, makes it easier than ever for researchers to add these techniques to their lab’s repertoire.

Warming up the stage

click to enlarge Fluxion’s BioFlux system allows researchers to image live cells inside a flow chamber that mimics the shear conditions of an artery.

For Olympus, time-lapse microscopy is hardly a new interest; the company has catered to hard-core microscopists with a long line of incubators and microscopes over the years. In October, though, Olympus introduced a series of streamlined systems aimed squarely at new users. The new products include the VivaView integrated microscope and incubator, which is designed especially for live-cell imaging.

“We’re able to not only support the people who are doing high-end cell culture who are really requiring the increased performance characteristics that they get with VivaView, but also people who are relatively new to ... live-cell imaging,” says Shand. In the VivaView system, the multi sample microscope stage sits inside a standard cell culture incubator. Researchers can place their cultured cells inside, set up an experiment through the included software interface, then acquire a series of time-lapse images over a period of several days, all without having to touch the plates or open the incubator.
The system has already proven popular with stem cell researchers. 

“It’s an area where of course the utmost in incubation is very important,” says Shand, adding that “We’ve actually introduced a second version of the system dedicated towards stem cell and tumor researchers. That system not only allows us to maintain and control carbon dioxide ... but also allows us to control the oxygen environment as well.”

Competing manufacturers are not letting the grass grow under their feet, though. Nikon, which introduced the first fully automated cell culture and microscopy systems, is now busily upgrading those products with new features and software. As Olympus was releasing VivaView, for example, Nikon announced its new image analysis software package, CL-Quant (pronounced “cell-quant”).

click to enlarge Nikon’s BioStation IM is an integrated system designed for long time-lapse imaging studies.

CL-Quant works with Nikon’s existing incubator-microscope systems, the Biostation CT and Biostation IM. The latter system is aimed specifically at biologists who want to do live-cell imaging, but don’t have a strong background in microscopy. “The Biostation IM is a single user, environmentally controlled, single dish, long-term, time-lapse imaging instrument,” says Ned Jastromb, senior applications product manager at Nikon Instruments in Melville, N.Y. Jastromb adds that “our customers can put their cells in and press ‘Play’ and basically conduct video microscopy very easily without a complicated additional inverted microscope.”

For those labs thatwant to track cell growth in multiple dishes, or for core facilities with multiple users, the Biostation CT is probably more appropriate. “You can choose multiple points within a well and the CT will remember those positions to acquire the time-lapse sequence, and then recreate that movie,” says Jastromb.

In addition, the software will remember the plate’s position even after it has been removed, allowing researchers to change media or add growth factors at any point during the experiment. Olympus’s VivaView offers a similar option.

Special needs
While the heavyweights of microscopy slug it out for the main time-lapse imaging market, other equipment makers are developing more specialized systems, often as a direct response to customers’ requests. Hamilton Robotics of Reno, Nev. provides a good example of this trend.

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“We worked together with a customer [who] likes to select clones for antibody production in hybridoma cells, and he wants to automate the process,” says Daniel Caminada, product manager for Hamilton’s CellHOST system. In a collaboration with the researcher, Caminada and his colleagues added an imaging module to the CellHOST, which is the company’s automated cell handler.

The result is a combination incubator, cell-manipulating robot, camera, and image analysis platform that can keep cells’ growing conditions optimized. “The first automated systems for cell cultures ... just had a fixed schedule and you just said ‘okay, after three days I have to subculture it on a new plate,’” says Caminada, adding that “this system allows you to get automated feedback and you can really feed your cells on demand.”

As the cells grow to confluence, the CellHOST can change their media more frequently. Hamilton optimized the proto-type for hybridoma cells, but Caminada says the system is equally good at handling several other standard cell lines.

Fluxion, of South San Francisco, Calif., also developed a new cell imaging product in response to a customer’s request. The company makes the popular BioFlux system, which allows researchers to study cells in a chamber of flowing liquid that mimics the shear conditions inside a blood vessel. The entry-level BioFlux mounts on any inverted microscope, while a more expensive model includes its own microscope for labs that need a dedicated system. The company’s disposable flow chambers fit either unit.

“We sold our BioFlux system to a big pharmaceutical company, and they were doing a lot of platelet aggregation, platelet inhibition work, [and] they pointed out that our plates covered what’s considered the physiological range ... but they said that in a disease state the cells see a much higher shear,” explains Mike Schwartz, program director at Fluxion.
 
In response, Fluxion developed a new high-shear plate that reproduces the high-shear conditions inside a plaque-clogged artery. The company designed the new plate to fit directly into the BioFlux imaging system, so researchers could start using it right away.

They did. “We’re finding about 25% to 30% of our customer base is using the high-shear plate, which is pretty significant,” says Schwartz. He adds that “We feel like we hit the market on the head here with one plate that immediately 30% of our customers are interested in. That exceeds our expectations.”

Fluxion, and the other companies in the field, are also hoping to roll out additional products in the near future, catering to both general-purpose cell imaging and more specialized techniques.

It’s a great time to be making movies.

About the Author
Originally trained as a microbiologist, Alan Dove has been writing about science and its interfaces with industry and government for more than a decade.

This article was published in Drug Discovery & Development magazine: Vol. 13, No. 2, March 2010, pp. 8-11.