Reversible Swelling and Shrinking of Paramagnetic Nanoparticle Swarms in Bio-fluids with High Ionic Strength
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AbstractMicrorobotic swarm has drawn extensive attention recently, due to its potential advantages in realtime tracking and targeted delivery in vivo. Herein, we use paramagnetic nanoparti- cles with a diameter of 500 μm as building blocks, to investigate the reversible pattern transformation of a swarm, i.e. swelling and shrinking, in bio-fluids by simulation and experiments. Three kinds of biofluids, i.e. phosphate buffered saline with Tween-20 (PBST), simulated blood and fetal bovine serum (FBS) are used, which have much higher ionic strength (up to 0.212 mol/L) and different viscosity compared with deionized water (DI water). Our results indicate that, except for the magnetic dipole interactions and hydrodynamic effects, the electrostatic interaction also plays an important role for swarm generation and reconfiguration in bio-fluids. The equivalent electrostatic torques exerted between nanoparticles, induced by ions, are quantified by an analytical model, and are successfully compensated by tuning applied magnetic fields. The input magnetic field has a maximum field strength of 10 mT, and a maximum frequency of 40 Hz. The experimental results validate the simulation, and meanwhile, the magnetic particle swarm is capable of performing significant swelling in the bio-fluids. In addition, by applying rotating magnetic fields, the swelled patterns can be reversibly shrunk into more concentrated regions.
All Author(s) ListYu Jiangfan, Zhang Li
Journal nameIEEE/ASME Transactions on Mechatronics
LanguagesEnglish-United Kingdom
KeywordsTorque, Viscosity, Magnetic nanoparticles, swarming pattern, bio-fluids, electrostatic interaction, Drag, magnetic actuation, Electrostatics, Magnetic moments, magnetic colloidal swarm

Last updated on 2020-22-05 at 01:19