AVS 52nd International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI1-TuA

Paper BI1-TuA6
Fluidic Force Discrimination Assays in Complex Media

Tuesday, November 1, 2005, 3:40 pm, Room 311

Session: Sensors/Diagnostics
Presenter: S.P. Mulvaney, Naval Research Laboratory
Authors: S.P. Mulvaney, Naval Research Laboratory
A.A. Glaser, Naval Research Laboratory
M. Malito, Naval Research Laboratory
C.R. Tamanaha, Naval Research Laboratory
J.C. Rife, Naval Research Laboratory
L.J. Whitman, Naval Research Laboratory
Correspondent: Click to Email
We are developing a highly sensitive and selective biosensor system that uses giant magnetoresistive sensors arrayed in a Bead ARray Counter (BARC) microchip to directly detect magnetic microbead labels. The beads are used both to label biorecognition events in a binding assay and to reduce background through a process known as fluidic force discrimination (FFD). FFD is a controlled bead removal procedure that leverages the strength of biomolecular recognition against fluidic forces to selectively remove nonspecifically bound beads and beads labeling nonspecifically bound analyte. FFD not only reduces the background label density, thereby improving the analytical sensitivity of the binding assay, but also lowers the occurrence of false positives. Highly sensitive DNA assays (<10 fM) and immunoassays (<1 ng/mL) have been demonstrated in less than 30 minutes at room temperature, without amplification or concentration steps (i.e. PCR). Successful assays have also been run in serum, plasma, whole blood, and complex environmental matrices. We'll discuss mitigation steps (i.e. addition of chelating agents, filtration, etc.) required to achieve detection in complex media as well the overall impact on detection levels. We'll also examine the ability to minimize sample handling by incorporating simple processing capabilities into the microfluidics cartridge. @FootnoteText@ S.P.M., A.A.G., and M.M. are employees of Nova Research Inc., Alexandria, Va.