According to Roderic I. Pettigrew, PhD, MD, director of the National Institute of Biomedical Imaging and Bioengineering (NIBIB), the biomedical research landscape is changing to reflect collaboration between the physical sciences and the life sciences, as typified by the synergy now seen between engineering and medicine. The four NIBIB grant projects described throughout this article represent technologically enabled fundamental understanding and discovery, which eventually lead to new preventive and therapeutic methods
The team headed by John C. Gore, PhD, at the Vanderbilt University Institute of Imaging Science, Nashville, Tenn, is studying bioluminescent imaging. Because it is sensitive to both molecular and cellular processes, bioluminescence may serve to link imaging to molecular biology. In the future, tomographic forms of imaging based on bioluminescence may become possible, and bioluminescent imaging might also be combined with MRI and/or other imaging modalities to create powerful new diagnostic tools.
The photoactive reporter gene luciferase can be imaged in living organisms. This property is being used in a mouse model to assess, over time, the progression of angiogenesis. The transgenic mice being used in this research carry the luciferase reporter and a human vascular endothelial growth factor. Living organisms emit visible light through the reaction of a luciferin substrate with molecular oxygen (catalyzed by luciferase). The resulting light is bioluminescence. The emitted light, which is yellow to red, appears as a result of a chemiluminescent reaction that requires none of the optical excitation needed for fluorescence.
In this work, an animal subject under anesthesia is placed before a charge-coupled bioluminescence camera for 3 minutes in order to generate a digital image through photon counting. Imaged over time, mice show an increase in bioluminescence that indicates expression of human vascular endothelial growth factor.