Magnetic nanoparticles for therapy and diagnosis are at the leading edge of the rapidly developing field of bionanotechnology. In this study, we have theoretically studied motion of magnetic nano- as well as micro-particles in the field of cylindrical Halbach array of permanent magnets. Magnetic flux density was modeled as magnetostatic problem by finite element method and particle motion was described using system of ordinary differential equations--Newton law. Computations were done for nanoparticles Nanomag-D with radius 65 nm, which are often used in magnetic drug targeting, as well as microparticles DynaBeads-M280 with radius 1.4 microm, which can be used for magnetic separation. Analyzing snapshots of trajectories of hundred magnetite particles of each size in the water as well as in the air, we have found that optimally designed magnetic circuits of permanent magnets in quadrupolar Halbach array have substantially shorter capture time than simple blocks of permanent magnets commonly used in experiments, therefore, such a Halbach array may be useful as a potential source of magnetic field for magnetic separation and targeting of magnetic nanoparticles as well as microparticles for delivery of drugs, genes, and cells in various biomedical applications.
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http://dx.doi.org/10.1007/s11517-010-0636-8 | DOI Listing |
ACS Nano
January 2025
Department of Bioengineering, University of Pennsylvania, 210 S. 33rd Street, 435 Skirkanich Hall, Philadelphia, Pennsylvania 19104, United States.
Nanoparticles have gained attention as drug delivery vehicles for cancer treatment, but often struggle with poor tumor accumulation and penetration. Single external magnets can enhance magnetic nanoparticle delivery but are limited to superficial tumors due to the rapid decline in the magnetic field strength with distance. We previously showed that a 2-magnet device could extend targeting to greater tissue depths.
View Article and Find Full Text PDFMicrosyst Nanoeng
December 2024
Research Center for Bionic Sensing and Intelligence, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China.
We present a versatile platform for label-free magnetic separation of plasma, tailored to accommodate diverse environments. This innovative device utilizes an advanced long-short alternating double Halbach magnetic array, specifically engineered for optimal magnetic separation. The array's adaptability allows for seamless integration with separation channels of varying sizes, enabling static separation of whole blood.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Department of Industrial and Materials Science, Chalmers University of Technology, Göteborg, 41296, Sweden.
Thermal conductivity enhancement in polymers is vital for advanced applications. This study introduces a novel method to align hexagonal boron nitride (hBN) nanosheets within polydimethylsiloxane (PDMS) matrices using a Halbach array to create a highly uniform magnetic field. This technique achieves significant improvements in thermal conductivity by effectively aligning hBN nanosheets.
View Article and Find Full Text PDFNat Commun
November 2024
State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin, 150080, China.
Soft machines respond to external magnetic stimuli with targeted shape changes and motions due to anisotropic magnetization, showing great potential in biomimetic applications. However, mimicking biological functionalities, particularly the complex hollow structures of organs and their dynamic behaviors, remains challenging. Here, we develop a printing method based on three-dimensional uniform magnetic field-assisted stereolithography to fabricate thin-walled soft machines with internal cavities and programmable magnetization.
View Article and Find Full Text PDFMAGMA
October 2024
C.J. Gorter MRI Center, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
Objective: To investigate the trade-off between magnet bore diameter and the distance between the conductive Faraday shield and RF head coil for low-field point-of-care neuroimaging systems.
Methods: Electromagnetic simulations were performed for three different Faraday shield geometries and two commonly used RF coil designs (spiral and solenoid) to assess the effects of a close-fitting shield on the RF coil's transmit and receive efficiencies. Experimental measurements were performed to confirm the accuracy of the simulations.
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