Giant magnetoresistance (GMR)
The electrical resistance of a metallic structure with several nanometers non-magnetic conducting thin film (e.g. copper) sandwiched between two ferromagnetic layers changes depending on the relative magnetization direction of the ferromagnetic layers.
Parallel magnetization results in lower resistance, while anti-parallel magnetization results in higher resistance. This phenomenon facilitates detection of stray fields from magnetic materials at nanometer scales.
A bead with magnetic nanoparticles added to a standard assay changes the local magnetization of a ferromagnetic layer in the GMR structure, which can be detected as a small change in resistance.
Bio-Surface And Magnetic Nanoparticles Bead Integration
Zepto Life’s on-chip bio-surface technology holds the capture antibodies in place. The bio-surface on the nanomagnetic particles allows them to be pre-labeled with detection antibodies. Analyte biomarkers are sandwich and specifically bound by capture and detection antibodies. Nanomagnetic particles would be attracted onto sensor surface and signal is read out real-time. Each biosensor is dedicated to a single biomarker.