Versatile magnetic configuration for the control and manipulation of superparamagnetic nanoparticles

Abstract

The control and manipulation of superparamagnetic nanoparticles (SP-MNP) is a significant challenge and has become increasingly important in various fields, especially in biomedical research. Yet, most of applications rely on relatively large nanoparticles, 50 nm or higher, mainly due to the fact that the magnetic control of smaller MNPs is often hampered by the thermally induced Brownian motion. Here we present a magnetic device able to manipulate remotely in microfluidic environment SP-MNPs smaller than 10 nm. The device is based on a specifically tailored configuration of movable permanent magnets. The experiments performed in 500 µm capillary have shown the ability to concentrate the SP-MNPs into regions characterized by different shapes and sizes ranging from 100 to 200 µm. The results are explained by straightforward calculations and comparison between magnetic and thermal energies. We provide then a comprehensive description of the magnetic field intensity and its spatial distribution for the confinement and motion of magnetic nanoparticles for a wide range of sizes. We believe this description could be used to establish accurate and quantitative magnetic protocols not only for biomedical applications, but also for environment, food, security, and other areas.

Magnetic–Plasmonic Nanoscale Liposomes with Tunable Optical and Magnetic Properties for Combined Multimodal Imaging and Drug Delivery

“…(a) Hysteresis loops of Fe 3 O 4 NP powder measured at 300 K; (b) UV–vis spectrum of 0.3 mg/mL Au–Fe 3 O 4 NPs. The inset shows Au–Fe 3 O 4 NPs magnetically separated after 48 h by the device described in ref . (c) HR-TEM image of the Au–Fe 3 O 4 and STEM-EDS elemental mapping for the chemical composition analysis.…”

“…Magnetic mobility measurements were performed with a dedicated experimental setup, developed at CNR-ISMN. , Briefly, a 500 μm wide quartz capillary was placed into a high-gradient magnetic field generated by a couple of cubic permanent magnets. The asymmetric location of the capillary, offset approximately 200 μm from the system’s central axis, enabled the concentration of magnetic components of the dispersion on one of its sides . A microscope-connected CCD camera closely tracked the response of the Au–Fe 3 O 4 NP-liposome hybrids (or Au–Fe 3 O 4 NPs) when they were exposed to a magnetic field.…”

“…The asymmetric location of the capillary, offset approximately 200 μm from the system's central axis, enabled the concentration of magnetic components of the dispersion on one of its sides. 44 A microscope-connected CCD camera closely tracked the response of the Au−Fe 3 O 4 NP-liposome hybrids (or Au− Fe 3 O 4 NPs) when they were exposed to a magnetic field. Within the dispersion, the magnetic field generated a drift of the magnetic objects toward the highest field regions, counteracted by Brownian motions.…”

Magnetic Nanoparticles and Magnetic Sensors for Ultrasensitive and Fast Diagnostics

“…We will also report on the very attractive option of magnetically enhancing by orders of magnitude the concentration of BMs in patient samples, thus providing the possibility to employ standard diagnostic techniques, such as ELISA, for concentrations well below their factual limits [4,5]. Moreover, the direct detection of a protein is demonstrated on the BSA-coated 20 nm large Fe 3 O 4 MNPs as to mimic the presence of a clinically important BM.…”

Nanoparticles in Medicine: Current Status in Cancer Treatment

“…Generally, magnetic-based technologies allow for guided in vivo and in vitro drug delivery by functionalized nanoparticle surfaces with use of an external magnetic field. Superparamagnetic nanoparticles are the preferable choice for this kind of applications, as they have low aggregation properties and high magnetization energy activated by the external magnetic field [ 72 ]. Cautious usage is, however, advised as recently several clinical trials on superparamagnetic iron oxide nanoparticles were stopped due to their toxicity in vivo [ 73 ].…”