AVS 50th International Symposium
    Homeland Security Topical Conference Thursday Sessions
       Session HS-ThM

Paper HS-ThM6
Microfluidic Approaches to Improving Biosensor Performance

Thursday, November 6, 2003, 10:00 am, Room 309

Session: Detection of Biological Agents and Self-Cleaning of Contaminated Surfaces
Presenter: J.C. Rife, Naval Research Laboratory
Authors: J.C. Rife, Naval Research Laboratory
P.E. Sheehan, Naval Research Laboratory
L.J. Whitman, Naval Research Laboratory
Correspondent: Click to Email
The sensitivity of a microarray biosensor depends on many factors other than the sensor performance, including sensor area, analyte diffusion, and non-specific binding of target and/or label. However, when the detection system is sensitive enough to detect single labels, the performance will be limited by these factors. We are confronting such limitations in the development of two systems for biowarfare pathogen detection. The Bead ARray Counter (BARC) and the Force Discrimination Biosensor (FDB) systems use biomolecular recognition to bind magnetic microbeads to either a solid or porous substrate. At our current detection limits, we are labeling one analyte molecule per detectable microbead. Under these conditions, the BARC system can detect DNA concentrations as low as 1 fM (10@super 5@ molecules/ml) and FDB can sense protein toxins at concentrations <0.5 pg/ml (10@super 6@ molecules/ml). Further gains in system performance will depend on careful design of the fluidics systems. We will present analytical and finite element calculations aimed at understanding and optimizing the microfluidic delivery of assay reagents to the sensor surfaces. The role of flow profile, fluidic forces, and sensor geometry in maximizing the assay performance will be discussed.