2018/04/26 by M. P. Nikitin, Nikitin, M. P., А. В. Орлов +15
Biochemistry, Genetics and Molecular Biology · Engineering · #Characterization and Applications of Magnetic Nanoparticles #FOS: Physical sciences #Geomagnetism and Paleomagnetism Studies #Materials Science (cond-mat.mtrl-sci) #Microfluidic and Bio-sensing Technologies
paper · pdf · doi:10.48550/arxiv.1804.09908
openalex publication_date 2018/04/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Geometrically confined magnetic particles due to their unique response to external magnetic fields find a variety of applications, including magnetic guidance, heat and drug delivery, magneto-mechanical actuation, and contrast enhancement. Highly sensitive detection and imaging techniques based on nonlinear properties of nanomagnets were recently proposed as innovative strong-translational potential methods applicable in complex, often opaque, biological systems. Here we report on significant enhancement of the detection capability using optical-lithography-defined, ferromagnetic iron-nickel alloy disk-shaped particles. We show that an irreversible transition between a strongly non-collinear (vortex) and single domain states, driven by an alternating magnetic field translates into a nonlinear magnetic response that enables ultrasensitive detection of these particles. The record sensitivity of ~ 3.5x10-9 emu, which is equivalent to ~39 pg of magnetic material is demonstrated at room temperature for arrays of patterned disks. We also show that unbound disks re-suspended in aqueous buffer can be successfully detected and quantified in real-time when administrated into a live animal allowing for tracing their biodistribution. Use of nanoscale ferromagnetic particles with engineered nonlinear properties opens prospects for further enhancing sensitivity, scalability and tunability of noise-free magnetic tag detection in high-background environments for various applications spanning from biosensing and medical imaging to anti-counterfeiting technologies.