Scientists in Germany are watching zebrafish grow up in a new drug screening technique.

Zebrafish embryos are already used for drug and toxicity testing as they have a number of advantages over other animal models and in vitro testing. These include their genetic similarity to humans, low cost and short experiment times, the small amount of drug required and the fact that the transparent embryos can be easily observed. Yet faster and cheaper drug-screening programs are needed to test the large numbers of new compounds that are being synthesised as potential drug candidates. ists in Germany are watching zebrafish grow up in a new drug screening technique.

Now, Michael Köhler and colleagues at the Technical University of Ilmenau have developed a screening process that could help meet these needs. They used a syringe pump to suck individual zebrafish eggs, surrounded by aqueous medium, into a thin coiled tube filled with an inert carrier fluid. Each suspended egg was separated from its neighbour by the inert liquid and an air bubble that acted as an oxygen supply.

The researchers monitored and photographed the various stages of the embryos' development using an optical microscope with an integrated digital camera. They showed that the zebrafish eggs can develop and hatch normally within the coiled tube.

The team showed the potential of the method in drug screening by using it to test the chemical effects of a detergent on embryo survival and development. Glenn Walker of the North Carolina State University in Raleigh in the US said the work 'is an exciting first step towards what one day may be a fully automated system for screening the toxic effects of compounds on embryos.'

Nicola Burton