Abstract
Magnetic nanoparticles are increasingly employed in biomedical applications such as disease detection and tumor treatment. To ensure a safe and efficient operation of these applications, a noninvasive and accurate characterization of the particles is required. In this work, a magnetic characterization technique is presented in which the particles are excited by specific pulsed time-varying magnetic fields. This way, we can selectively excite nanoparticles of a given size so that the resulting measurement gives direct information on the size distribution without the need for any a priori assumptions or complex postprocessing procedures to decompose the measurement signal. This contrasts state-of-the-art magnetic characterization techniques. The possibility to selectively excite certain particle types opens up perspectives in “multicolor” particle imaging, where different particle types need to be imaged independently within one sample. Moreover, the presented methodology allows one to simultaneously determine the size-dependent coercivity of the particles. This is not only a valuable structure–property relation from a fundamental point of view, it is also practically relevant to optimize applications like magnetic particle hyperthermia. We numerically demonstrate that the novel characterization technique can accurately reconstruct several particle size distributions and is able to retrieve the coercivity–size relation of the particles. The developed technique advances current magnetic nanoparticle characterization possibilities and opens up exciting pathways for biomedical applications and particle imaging procedures.
Highlights
Magnetic nanoparticles (MNPs) exhibit many properties that make them useful for biomedical applications [1,2,3]
An alternative nanoparticle characterization approach is presented that tackles the aforementioned problems: it does not require a complex measurement decomposition with assumptions on particle size distributions and it is able to simultaneously unveil the relation between the coercivity and particle size for suspended particles. This is accomplished by employing specific magnetic fields that exploit the interplay between the magnetic and rotational dynamics of the MNPs, so only particles with a specific coercivity are excited by the applied field
We present a worst case scenario, in which this effect is larger than it would be in most measurements, and it is further amplified by the fact that we consider a large Hext amplitude range from 0 to 50 mT
Summary
Magnetic nanoparticles (MNPs) exhibit many properties that make them useful for biomedical applications [1,2,3]. An accurate characterization of the nanoparticle properties is important to ensure the reliable, efficient, and safe operation of the applications mentioned above To this end, several magnetic characterization methods exist in which the MNP response to specific magnetic field sequences is measured to unveil their underlying size distribution [11]; a key parameter in determining application performance [12,13]. An alternative nanoparticle characterization approach is presented that tackles the aforementioned problems: it does not require a complex measurement decomposition with assumptions on particle size distributions and it is able to simultaneously unveil the relation between the coercivity and particle size for suspended particles This is accomplished by employing specific magnetic fields that exploit the interplay between the magnetic and rotational dynamics of the MNPs, so only particles with a specific coercivity are excited by the applied field. This is followed by a discussion on the possible advantages of using our technique in magnetic particle imaging in Section 8, before finishing with the conclusion
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
