Magnetic Nanoparticle Biosensor 2D: GMR Spin-Valve Diagnostic Chip

Point-of-care diagnostics increasingly read biomarker binding magnetically instead of optically. This 2D simulator models a giant-magnetoresistance (GMR) spin-valve biosensor chip from directly above: antibody-functionalized superparamagnetic nanoparticles bind a capture-site array following real Langmuir adsorption kinetics, an external bias field magnetizes each bound label, and the sensor's resistance shifts in response to the combined dipole stray field of every bound particle. Drag the array to pan across the chip, tune analyte concentration, bias field, nanoparticle core size and antibody off-rate, and watch the bound-particle count, fractional surface coverage, the live ΔR/R resistance trace and the sensor's transfer-curve operating point respond exactly as a real spin-valve immunoassay would.