An Ultra-Broadband Magnetic Susceptivity Evaluation of Magnetic Nanoparticle and Protein

A new broad bandwidth detection of the GDF15 protein (Growth Differentiation Factor-15), which utilizes the broad bandwidth observation up to 67 GHz, has been proposed. We prepared the sandwich-type bound method using a primary and secondary antibody with additional magnetic nanoparticles on an Au film. A DC field application enhanced sharp ferromagnetic resonance, which improved the signal-to-noise ratio of detecting GDF15. The density of GDF15 changed as follows: 0, 0.5, 5, and
$\mathbf{50}\ \mu \mathbf{g}/\mathbf{ml}$
. The magnetic susceptivity and FMR intensity increased clearly with the increase of the GDF15 density.