Seeing the shimmer of biology in action  pg. 3

New software is improving the spatial resolution of bioluminescence imaging.  In these test images, a luminescent bead has been implanted inside a silicon mouse model.  On the left, a "standard" planar bioluminescence image shows light scattered as it moves through the model mouse.  The image on the right shows the result of bioluminescence tomography using Xenogen's Living Image Software 3D Analysis Package.  The red pixel indicates the reconstructed light source location.

Courtesy of Jack Virostko, graduate student in the lab of E. Duco Jansen, Ph.D.

Christopher Contag remained at Stanford. “I decided to take a very broad approach and demonstrate the breadth of this technology,” he says. “So we’ve been tracking viruses and tumor cells and stem cells, and in the early days attempted to show how versatile this technology is. Now we’re focusing on stem cells and cancer biology.”

Light bulbs inside cells

Investigators at Vanderbilt embraced bioluminescence imaging early on to follow cells and gene expression in living animals. Watching cells as they migrate through a living animal, take up residence, multiply, and in the case of tumor cells, metastasize to new sites, has been the most popular application of bioluminescence to date.

“What bioluminescence gives you is a level of sensitivity of detection that is not attainable by any other current method,” says E. Duco Jansen, Ph.D., associate professor of Biomedical Engineering at Vanderbilt.

The way it works is conceptually quite simple, Jansen explains. Cells of any sort can be infected with viruses or engineered to incorporate a luciferase gene. After being injected into small animals, usually mice, the cells begin to produce the luciferase protein. Investigators then inject the substrate molecule—such as luciferin—into the animals, and the luciferase acts on it, releasing photons of light.