A New Tool Expands Microscope Capabilities

A new confocal microscope attachment called FLIM, purchased with funds from the American Recovery and Reinvestment Act (ARRA), will allow scientists in the Intramural Research Program (IRP) at the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) to probe biomedical images with increased precision.

Confocal microscopes like the one used by NIAMS researchers narrow the depth of field of an image so that an area of interest, even deep in a piece of tissue, can be in focus. The resulting three-dimensional pictures and measurements give a detailed view inside cells, at the limit of resolution. FLIM, or Fluorescence Lifetime Imaging Microscopy, allows the confocal microscope to detect additional information about individual molecules, allowing scientists to learn more from each image.

"FLIM gives us a glimpse into the intrinsic properties of a fluorescent molecule, which are affected by its environment," says Evelyn Ralston, Ph.D., chief of the IRP's Light Imaging Section. "Most often, the instrument is used to investigate fluorescent molecules attached to a protein, and it's a most useful way to find out when the protein is on its own and when it forms a pair with another protein. From such measurements, we can, for example, obtain information about the energy state of skeletal muscle and discover differences between healthy and diseased muscle."

Images produced by confocal microscopy usually rely on viewing fluorescent markers specifically bound to the samples under investigation. Biological features are often distinguished by different marker colors, and data are obtained using parameters such as location, shape and color intensity. FLIM, however, adds an additional dimension of analysis by tracking the decay time of the fluorescent signal, rather than its intensity. Signal decay times are specific to particular fluorophores, or components of a molecule that cause it to fluoresce.

"Imaging has always been a critical component of our clinical and basic research efforts," says John O'Shea, M.D., IRP scientific director and chief of its Molecular Immunology and Inflammation Branch. "Our acquisition of FLIM technology will help propel us to a new level of knowledge about the molecular landscape."

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The activity above is being funded through the American Recovery and Reinvestment Act (ARRA). More information about the National Institutes of Health's ARRA grant funding opportunities can be found at https://grants.nih.gov/recovery/. To track the progress of HHS activities funded through the ARRA, visit www.hhs.gov/recovery. To track all federal funds provided through the ARRA, visit www.recovery.gov.