AVS 47th International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI+NS-ThA

Paper BI+NS-ThA6
BARC: A Magnetoresistive Biosensor@footnote 1@

Thursday, October 5, 2000, 3:40 pm, Room 202

Session: Biosensors
Presenter: P.E. Sheehan, Naval Research Laboratory
Authors: P.E. Sheehan, Naval Research Laboratory
R.L. Edelstein, Geo-Centers, Inc.
C.R. Tamanaha, Naval Research Laboratory
M. Miller, Naval Research Laboratory
L. Zhong, Geo-Centers, Inc.
R.J. Colton, Naval Research Laboratory
L.J. Whitman, Naval Research Laboratory
Correspondent: Click to Email
The Bead ARray Counter (BARC) is a revolutionary biosensor that uses DNA microarrays, magnetic microbeads, and giant magnetoresistive (GMR) magnetic field sensors to detect and identify biological molecules.@footnote 2@ The current prototype is a table-top instrument with integrated fluidics under development for the detection of biological warfare agents. The core of the sensor is a small, microfabricated chip containing a GMR sensor array for detection of up to eight different pathogens. Oligonucleotide probes complementary to pathogen target sequences are arrayed onto the microfabricated chip directly above the GMR sensors. Specific hybridization is measured and discriminated from non-specific background by addition of functionalized magnetic microbeads that bind to the captured target DNA. The beads tethered to the surface are detected by the GMR sensors, with the intensity and location of the signal indicating the concentration and identity of the target pathogens. A complete assay, including hybridization and detection can be performed in approximately 30 min. Because each GMR sensor is capable of detecting a single magnetic bead, in theory, the BARC biosensor should be capable of detecting a single molecule. With recent advances in GMR technology for computer memory, chips with millions of sensors will soon be commercially available, enabling the development of a BARC sensor capable of detecting thousands of analytes simultaneously. We will discuss the scientific and technical challenges to making such a sensor system a reality. @FootnoteText@ @footnote 1@Supported by the Defense Advanced Research Projects Agency. @footnote 2@Edelstein et al., Biosensors & Bioelectronics 14, 805 (2000).