Lowering the Risks of Biotesting

Most current forensic or human identity tests require use of film and radioactive isotopes. These tests can be expensive, not only because of the material involved, but also because of safety precautions and disposal costs associated with the test materials. However, a collaboration between Gaithersburg-based Life Technologies Inc. (LTI) and Hitachi Software Engineering America should help make the tests safer and quicker, as well as lower their cost.

Laser fluorescent systems currently are used in routine application research, such as gene map- ping, said Leonard Klevan, LTI's director of new business development. The new technologies focus on human identification, such as paternity or forensic testing -- verifying that DNA evidence is from a suspect, Klevan said.

Currently, when testing DNA samples, the DNA is placed on a membrane or gel, and would be hybridized -- or linked -- to a radioactive probe, then film is placed over the sample. The radioactivity causes an exposure pattern on the film.

Following this, the film is analyzed, either visually, or most often it is transferred into a computer and a computer program runs comparisons and analyzes the data.

Radioactivity is always a concern in labs, and there are very stringent guides to deal with it, said Chris Culotta, LTI spokes-man. Lab technicians are reluctant to work with radioactive material, he said.

Another common method uses chem-illuminescence, which operates similarly, and, although not as hazardous, is expensive, Culotta said.

The technology that Hitachi and LTI are working on would offer the same resolution and sensitivity as the radioactive film method, but without the risk.

Like the radioactive method, the sample is put on a membrane or gel, and is hybridized to a probe containing the fluorescent material, said Klevan. Unlike the radioactive method, a laser scans the material, then digitally feeds the collected data directly into a computer, instead of requiring a two-step process to input it, he said.

LTI is working on ways to improve the DNA transfer from the membrane or gel to the probe and also on the detection systems, Klevan said.

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