Handheld Biosensor using Magnetic Labels and Giant Magnetoresistive Sensors with Fluid Force Discrimination

Seahawk Biosystems is developing a handheld version of the company's Talon Biosensor. The Talon Biosensor is based on the technology developed at the Naval Research Laboratory for multiplexed detection of proteins, bacteria, and viruses, including nucleic acids and toxins. The Talon Biosensor uses magnetic microbeads to label biomolecules captured onto a receptor-patterned microchip that contains a microarray of magnetic sensors. Besides serving as reporter labels, the microbeads allow fluidic force discrimination-greatly reducing background signal-enabling the rapid identification of biomolecules with high sensitivity and specificity. The Talon Biosensor has been adapted for both nucleic acid assays and immunoassays, with unmodified DNA detected at 10fM in <20 minutes and a 2 microgram/mL IgG target detected in a 50 microliter sample in <10 minutes. Seahawk's Talon Biosensor offers numerous advantages over competing systems. Assays use a physical label and chip-based detection (no optics), with no chemistry required other than molecular recognition. The assay and detection platforms are simple and compact, and minimal sample processing is required. Moreover, the use of force discrimination greatly increases the signal-to-background ratio, reducing false positives and increasing the sensitivity. Finally, the approach is extremely flexible, easily adapted to any "sandwich" assay that can be labeled with a microbead.