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Abstract Magnetic particle imaging (MPI) is a tracer-based tomographic imaging technique utilized in applications such as lung perfusion imaging, cancer diagnosis, stem cell tracking, etc. The goal of translating MPI to clinical use has prompted studies on further improving the spatial-temporal resolutions of MPI through various methods, including image reconstruction algorithm, scanning trajectory design, magnetic field profile design, and tracer design. Iron oxide magnetic nanoparticles (MNPs) are favored for MPI and magnetic resonance imaging (MRI) over other materials due to their high biocompatibility, low cost, and ease of preparation and surface modification. For core–shell MNPs, the tracers’ magnetic core size and non-magnetic coating layer characteristics can significantly affect MPI signals through dynamic magnetization relaxations. Most works to date have assumed an ensemble of MNP tracers with identical sizes, ignoring that artificially synthesized MNPs typically follow a log-normal size distribution, which can deviate theoretical results from experimental data. In this work, we first characterize the size distributions of four commercially available iron oxide MNP products and then model the collective magnetic responses of these MNPs for MPI applications. For an ensemble of MNP tracers with size standard deviations ofσ, we applied a stochastic Langevin model to study the effect of size distribution on MPI imaging performance. Under an alternating magnetic field (AMF), i.e., the excitation field in MPI, we collected the time domain dynamic magnetizations (M-t curves), magnetization-field hysteresis loops (M-H curves), point-spread functions (PSFs), and higher harmonics from these MNP tracers. The intrinsic MPI spatial resolution, which is related to the full width at half maximum (FWHM) of the PSF profile, along with the higher harmonics, serve as metrics to provide insights into how the size distribution of MNP tracers affects MPI performance.
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This content will become publicly available on February 13, 2026
Advances in magnetic nanoparticles for molecular medicine
Magnetic nanoparticles (MNPs) are highly versatile nanomaterials in nanomedicine, owing to their diverse magnetic properties, which can be tailored through variations in size, shape, composition, and exposure to inductive magnetic fields. Over four decades of research have led to the clinical approval or ongoing trials of several MNP formulations, fueling continued innovation. Beyond traditional applications in drug delivery, imaging, and cancer hyperthermia, MNPs have increasingly advanced into molecular medicine. Under external magnetic fields, MNPs can generate mechano- or thermal stimuli to modulate individual molecules or cells deep within tissue, offering precise, remote control of biological processes at cellular and molecular levels. These unique capabilities have opened new avenues in emerging fields such as genome editing, cell therapies, and neuroscience, underpinned by a growing understanding of nanomagnetism and the molecular mechanisms responding to mechanical and thermal cues. Research on MNPs as a versatile synthetic material capable of engineering control at the cellular and molecular levels holds great promise for advancing the frontiers of molecular medicine, including areas such as genome editing and synthetic biology. This review summarizes recent clinical studies showcasing the classical applications of MNPs and explores their integration into molecular medicine, with the goal of inspiring the development of next-generation MNP-based platforms for disease treatment.
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- Award ID(s):
- 2342391
- PAR ID:
- 10580400
- Publisher / Repository:
- Royal society of chemistry
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 61
- Issue:
- 15
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 3093 to 3108
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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