To the Theory of Ferrohydrodynamic Circulating Flow Induced by Running Magnetic Field

We present results of theoretical modeling of macroscopic circulating flow induced in a drop of ferrofluid by oscillating running magnetic field. The drop is placed in a narrow flat channel filled by a nonmagnetic liquid. The aim of this work is development of a scientific basis for a progressive method of address drug delivery to thrombus clots in blood vessels with the help of the magnetically induced circulation flow. Our results show that the oscillating running field allows inducing the carrier fluid flow with velocity amplitude 1–10 cm/s. This is the range of values, presenting interest from the point of view of the drug delivery. © 2020, EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature

Field-induced circulation flow in magnetic fluids

In this paper, we present results of a theoretical study of circulation flow in ferrofluids under the action of an alternating inhomogeneous magnetic field. The results show that the field with the amplitude of about 17 kA m−1 and angular frequency 10 s−1 can induce mesoscopic flow with a velocity amplitude of about 0.5 mm s−1. This mechanism can be used for intensification of drag delivery in blood vessels. © 2020 The Author(s) Published by the Royal Society. All rights reserved.Agence Nationale de la Recherche, ANRMinistry of Education and Science of the Russian Federation, Minobrnauka: FEUZ-2020-005119-31-90003, 18-08-00178, 20-02-00022Data accessibility. This article has no additional data. Authors’ contributions. P.K. and G.V.-D.: the physical idea of the study. A.Z.: mathematical model. A.M. and M.R.-M.: calculations. Competing interests. We declare we have no competing interests. Funding. The work was supported by the Russian Fund of Basic Researches, projects 18-08-00178, 19-31-90003 and 20-02-00022; by the programme of the Ministry of Education and Science of the Russian Federation, project FEUZ-2020-0051; by French ‘Agence Nationale de la Recherche’, Project Future Investments UCA JEDI, No. ANR-15-IDEX-01 (projects ImmunoMag and MagFilter) and by the private company Axlepios Biomedicals

Kinetics of field-induced phase separation of a magnetic colloid under rotating magnetic fields

This paper is focused on the experimental and theoretical study of the phase separation of a magnetic nanoparticle suspension under rotating magnetic fields in a frequency range, 5 Hz ≤ ν ≤ 25 Hz, relevant for several biomedical applications. The phase separation is manifested through the appearance of needle-like dense particle aggregates synchronously rotating with the field. Their size progressively increases with time due to the absorption of individual nanoparticles (aggregate growth) and coalescence with neighboring aggregates. The aggregate growth is enhanced by the convection of nanoparticles toward rotating aggregates. The maximal aggregate length, Lmax ∝ ν-2, is limited by fragmentation arising as a result of their collisions. Experimentally, the aggregate growth and coalescence occur at a similar timescale, ∼1 min, weakly dependent on the field frequency. The proposed theoretical model provides a semi-quantitative agreement with the experiments on the average aggregate size, aggregation timescale, and size distribution function without any adjustable parameter. © 2020 Author(s).We are grateful to Dr. A. Bee and Dr. D. Talbot from PHENIX laboratory at Sorbonne University (Paris, France) for providing us with the parent ferrofluid. P.K. acknowledges the French “Agence Nationale de la Recherche,” Project Future Investments UCA JEDI, Grant No. ANR-15-IDEX-01 (projects ImmunoMag and MagFilter) and the private company Axlepios Biomedical for financial support, and J.Q.C. acknowledges the financial support of UCA JEDI and Axlepios Biomedical through the PhD fellowship. A.Z. thanks the Russian Science Foundation, Project No. 20-12-00031, for financial support

Nonlinear theory of macroscopic flow induced in a drop of ferrofluid

We present results of theoretical modelling of macroscopic circulating flow induced in a cloud of ferrofluid by an oscillating magnetic field. The cloud is placed in a cylindrical channel filled by a nonmagnetic liquid. The aim of this work is the development of a scientific basis for a progressive method of addressing drug delivery to thrombus clots in blood vessels with the help of the magnetically induced circulation flow. Our results show that the oscillating field can induce, inside and near the cloud, specific circulating flows with the velocity amplitude about several millimetres per second. These flows can significantly increase the rate of transport of the molecular non-magnetic impurity in the channel. This article is part of the theme issue 'Transport phenomena in complex systems (part 1)'. © 2021 The Author(s).Agence Nationale de la Recherche, ANR: ANR-15-IDEX-01; Russian Science Foundation, RSF: 20-12-00031Data accessibility. Source code and numerical data has been provided as electronic supplementary material. Authors’ contributions. A.Y.Z. and P.K. were involved in problem statement and development of the mathematical model. D.C., M.R.M. and G.V.D. were involved in analytical and numerical calculations. Competing interests. We declare we have no competing interests Funding. A.Z. and D.C. thanks the Russian Science Foundation, project 20-12-00031, for the financial support. P.K. and M.R.M. thank the funding of French ‘Agence Nationale de la Recherche’, Project Future Investments UCA JEDI, No. ANR-15-IDEX-01 (projects ImmunoMag and MagFilter) and by the private company Axlepios Biomedical

Kinetics of phase separation of magnetic colloids in rotating magnetic fields

Работа выполнена при поддержке РФФИ (грант 19-31-60036)