Magnetically Labeled GMR Biosensor With a Single Immobilized Ferrimagnetic Particle Agent for the Detection of Extremely Low Concentration of Biomolecules

It was numerically and experimentally demonstrated that “one giant magnetoresistance (GMR) biosensor + single ferrimagnetic nanoparticle or micro particle sensor agent” architecture is more technically suitable for the detection of extremely low concentration of biomolecules than the “one GMR biosensor + single superparamagnetic nanoparticle sensor agent” architecture. The large remnant magnetization of a single immobilized ferrimagnetic nano or micro particle sensor agent that allows for, producing a sufficiently large stray magnetic field, maintaining negligibly small variation of interaction factor (IF) formed between the agent and the free layer (sensing layer) of the GMR biosensor, and a larger “effective sensing area” directly corresponding to a practically larger optimized sensor size, were found to be the main physical reasons for the technical promises.