Scientists at the Naval Research
Laboratory (NRL) are developing a novel, high-sensitivity biosensor
for applications in environmental monitoring of airborne or water-borne
contaminants and clinical tests where ultra-sensitive detection
is needed.
The force amplified biological
sensor (FABS) uses ultra-sensitive force transducers to detect
molecular recognition forces between DNA molecules, metal ions-chelators,
antibodies antigens, or other ligand-receptor molecules. The
transducers, originally developed for atomic force microscopy,
are sensitive enough to detect the forces between a single pair
of molecules. This gives FABS near-single-molecule sensitivity,
an improvement of six to eight orders of magnitude over competitive
techniques. The transducers are also micromachined, so FABS devices
could eventually be miniaturized.
Presently, the NRL team, led
by Drs. Gil Lee, David Baselt and Richard Colton of the Chemistry
Division's Surface Chemistry Branch, is concentrating on antibody-antigen
interactions and developing the FABS hardware.
The instrument uses an immunobead
assay consisting of a cantilever force transducer to which antibodies
have been bound. When the sample solution is introduced into
the instrument, the antibodies bind any antigen -- the protein,
virus, or bacterium of interest -- that might be present. Micron-sized,
antibody-coated magnetic particles then bind to another part
of the antigen, creating a particle-antigen-cantilever sandwich.
After washing away excess particles, a magnetic field is turned
on, which pulls on the particles, causing the cantilever to bend.
The amount of bending indicates how many particles are bound
to the cantilever, and therefore, how much antigen was present
in the sample. The assay is expected to take about ten minutes
to run.
The U.S. Naval Research Laboratory is the Navy's full-spectrum corporate laboratory, conducting a broadly based multidisciplinary program of scientific research and advanced technological development. The Laboratory, with a total complement of nearly 2,500 personnel, is located in southwest Washington, D.C., with other major sites at the Stennis Space Center, Miss., and Monterey, Calif. NRL has served the Navy and the nation for over 85 years and continues to meet the complex technological challenges of today's world. For more information, visit the NRL homepage or join the conversation on Twitter, Facebook, and YouTube.
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