Diffusion limited field induced aggregation of magnetic liposomes

Licínio, Pedro; Frézard, Frédéric

doi:10.1590/s0103-97332001000300004

Cited by 8 publications

(4 citation statements)

References 14 publications

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“…However, it is reported, from electron microscopic observations, that the shape anisotropy of the fine particles arising from the nonsphericity of particles is very small in ferrofluids in comparison with the large optical anisotropy created in the chain formation in the presence of applied magnetic field. No optical signal changes in zero applied fields for these surfactant-coated ferrofluids was observed [26][27][28][29]. In the magneto-transverse mode, the eigenmodes are linearly polarized waves making the dependence quadratic in applied magnetic field.…”

Section: Article In Pressmentioning

confidence: 86%

Magnetic field-induced cluster formation and variation of magneto-optical signals in zinc-substituted ferrofluids

Nair

Rajesh

Abraham

et al. 2006

Journal of Magnetism and Magnetic Materials

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Fine magnetic particles (sizeffi100 Å ) belonging to the series Zn x Fe 1Àx Fe 2 O 4 were synthesized by cold co-precipitation methods and their structural properties were evaluated using X-ray diffraction. Magnetization studies have been carried out using vibrating sample magnetometry (VSM) showing near-zero loss loop characteristics. Ferrofluids were then prepared employing these fine magnetic powders using oleic acid as surfactant and kerosene as carrier liquid by modifying the usually reported synthesis technique in order to induce anisotropy and enhance the magneto-optical signals. Liquid thin films of these fluids were prepared and field-induced laser transmission through these films was studied. The transmitted light intensity decreases at the centre with applied magnetic field in a linear fashion when subjected to low magnetic fields and saturate at higher fields. This is in accordance with the saturation in cluster formation. The pattern exhibited by these films in the presence of different magnetic fields was observed with the help of a CCD camera and was recorded photographically. r

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Section: Article In Pressmentioning

confidence: 86%

Magnetic field-induced cluster formation and variation of magneto-optical signals in zinc-substituted ferrofluids

Nair

Rajesh

Abraham

et al. 2006

Journal of Magnetism and Magnetic Materials

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“…So far, magnetically induced aggregation has been experimentally investigated by different techniques being particularly focused on the study of superparamagnetic polystyrene particles. For instance, light scattering has been used to probe aggregation kinetics and/or aggregate structure [50][51][52][53][54][55][56] whereas two-dimensional microscopy images have been analyzed to look into the cluster morphology [51,52,[55][56][57][58]. Apart from studies on real systems, simulations and analytical approaches have also been proposed to rationalize the aggregation of ferro-and superpara-magnetic particles where magnetic interaction is treated in terms of a dipolar hard-sphere like model [59][60][61][62][63].…”

Section: Introductionmentioning

confidence: 99%

Reversible and irreversible aggregation of magnetic liposomes

et al. 2017

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Understanding stabilization and aggregation in magnetic nanoparticle systems is crucial to optimizing the functionality of these systems in real physiological applications. Here we address this problem for a specific, yet representative, system. We present an experimental and analytical study on the aggregation of superparamagnetic liposomes in suspension in the presence of a controllable external magnetic field. We study the aggregation kinetics and report an intermediate time power law evolution and a long time stationary value for the average aggregate diffusion coefficient, both depending on the magnetic field intensity. We then show that the long time aggregate structure is fractal with a fractal dimension that decreases upon increasing the magnetic field intensity. By scaling arguments we also establish an analytical relation between the aggregate fractal dimension and the power law exponent controlling the aggregation kinetics. This relation is indeed independent on the magnetic field intensity. Despite the superparamagnetic character of our particles, we further prove the existence of a population of surviving aggregates able to maintain their integrity after switching off the external magnetic field. Finally, we suggest a schematic interaction scenario to rationalize the observed coexistence between reversible and irreversible aggregation.

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“…In some cases, the growth of aggregates shows scale invariance that can be described in terms of fractal dimensions [10,11]. Magnetic particles [6,12,13], magneto-rheological fluids [14,7,8,9], organicsolvent-based magnetic fluids [15] or magnetic liposomes [16] have been the object of several experimental investigations.…”

mentioning

confidence: 99%

“…It can be obtained by adjusting the scattering intensity I with the scattering vector q between the Guinier and the Porod regimes, where I ∝ q −D f [17] is verified. All of the values relating chain-like structures of magnetic particles are contained in an interval D f = 1.1 − 1.3 [16,15,7,8,9], reflecting a linear structure of the aggregates, because of the alignment with the ex- Figure 1: Scheme of the video-microscopy setup [22].…”

mentioning

confidence: 99%

Morphology of anisotropic chains in a magneto-rheological fluid during aggregation and disaggregation processes

Domínguez-García¹,

Melle²,

Rubio³

2009

Journal of Colloid and Interface Science

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We study the morphology of the chain-like aggregates formed when a external constant and uniaxial magnetic field is applied to a magneto-rheological (MR) fluid. In order to characterize the conformation of the aggregates, we study the evolution of various fractal dimensions during aggregation and disaggregation processes (i.e., when the applied field is switched on and off), using video-microscopy and image analysis. Experiments have been performed by varying the values of two external parameters: the magnetic field amplitude and particle concentration. We found that the box-counting dimension, related with how the aggregates occupy the surrounding space, depends on the ratio R 1 /R 0 . During the first stage of the disaggregation process, when the particles are moving by Brownian motion inside the aggregate, Family-Vicsek scaling function is verified.

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Diffusion limited field induced aggregation of magnetic liposomes

Cited by 8 publications

References 14 publications

Magnetic field-induced cluster formation and variation of magneto-optical signals in zinc-substituted ferrofluids

Magnetic field-induced cluster formation and variation of magneto-optical signals in zinc-substituted ferrofluids

Reversible and irreversible aggregation of magnetic liposomes

Morphology of anisotropic chains in a magneto-rheological fluid during aggregation and disaggregation processes

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