Detection of magnetic nanoparticles (MNPs) using spin current nano-oscillator (SCNO) biosensor: A frequency-based rapid, ultra-sensitive, magnetic bioassay

TL;DR

This study demonstrates through micromagnetic simulations that a spin current nano-oscillator (SCNO) can serve as a highly sensitive, frequency-based biosensor capable of detecting individual magnetic nanoparticles by observing shifts in ferromagnetic resonance peaks.

Contribution

It introduces a novel application of SCNO as a rapid, ultra-sensitive magnetic bioassay device capable of single nanoparticle detection using frequency shifts.

Findings

Detects single MNPs via resonance peak shifts

Shows sensitivity despite thermal noise

Identifies position-sensitive behavior of SCNO

Abstract

This Letter is a micromagnetic simulation-based study on the GHz-frequency ferromagnetic resonances for the detection of magnetic nanoparticles (MNPs) using spin current nano-oscillator (SCNO) operating in precession mode as a spintronic biosensor. The magnetic stray fields from the MNPs in an antibody-antigen-MNP complex on the SCNO surface modify the ferromagnetic resonance peaks and generate measurable resonance peak shifts. Moreover, our results strongly indicate the position-sensitive behavior of the SCNO biosensor and ways to eradicate this effect to facilitate better bio-sensing performance. Additionally, a study has been made on how nanoparticles with different sizes can alter the SCNO device performance. This simulation-based study on the SCNO device shows a promise of frequency-based nano-biosensor with a sensitivity of detecting even a single MNP, even in presence of thermal noise.