One of the most commonly studied laboratory animals is the zebrafish — a tiny fish with transparent embryos whose internal organs can easily be seen as they develop. Because they are genetically similar to humans and have complex organs, zebrafish are used by biologists as a model for human diseases such as cancer, liver disease, and heart disease. Researchers need several minutes to visually examine each larva, however, so they’re reluctant to use the fish in experiments that require a large number of animals — for example, when testing the effects of many different drugs.

With the goal of speeding the process and enabling large-scale studies, engineers at MIT have developed a technique that can analyze zebrafish larvae in seconds. The researchers, led by Mehmet Fatih Yanik, PhD, associate professor of electrical engineering and computer science, describe the technology in Nature Methods. “Ours is the only system that can take a large library of chemicals and screen it on thousands of vertebrates,” Yanik says.

With the MIT system, larvae are pumped from a holding area to an imaging platform, where they are automatically rotated so the area of greatest interest can be seen. This is important because if the larvae are in the wrong position, the yolk or pigmentation on the skin may block the organs the researcher wants to observe. The animals remain unharmed throughout the process. The microscope’s resolution is high enough to image individual cells, and the entire process takes about 19 seconds per animal, compared to about 10 minutes for manual inspection. To demonstrate the system’s effectiveness, the MIT team imaged the neurons that project from the zebrafish retina to the brain. The system also could be used to observe tumor growth, organ regeneration, or stem cell migration, according to Yanik. The team has applied for a patent on the device and is preparing for commercial applications.

Source:  Nanowerk

Posted July 28th, 2010 under Tech Transfer

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