Sedimentation Kinetics of Magnetic Nanoparticle Clusters: Iron Oxide Nanospheres vs Nanorods

Ng, Wei Ming; Katiyar, Akshit; Mathivanan, V.; Teng, Xiau Jeong; Leong, Sim Siong; Low, Siew Chun; Lim, JitKang

doi:10.1021/acs.langmuir.0c00135

Cited by 17 publications

(26 citation statements)

References 47 publications

(92 reference statements)

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“…Additionally, the trivial effect of gravitational sedimentation on magnetophoresis has also been demonstrated in our experiments using a TODA magnetic nanorod (with a diameter of ∼20 nm and a length of ∼300 nm). 56,84 In the presence of a low-gradient magnetic field generated by a hand-held cylindrical magnet, the removal of a magnetic nanorod can be accomplished within 3 min. 56 On the other hand, under the action of only gravitational force (in the absence of a magnetic field), complete settling out of a magnetic nanorod is still not yet achieved after 100 min of gravitational sedimentation.…”

Section: ■ Fundamental Conceptsmentioning

confidence: 99%

Unified View of Magnetic Nanoparticle Separation under Magnetophoresis

et al. 2020

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The migration process of magnetic nanoparticles and colloids in solution under the influence of magnetic field gradients, which is also known as magnetophoresis, is an essential step in the separation technology used in various biomedical and engineering applications. Many works have demonstrated that in specific situations, separation can be performed easily with the weak magnetic field gradients created by permanent magnets, a process known as low-gradient magnetic separation (LGMS). Due to the level of complexity involved, it is not possible to understand the observed kinetics of LGMS within the classical view of magnetophoresis. Our experimental and theoretical investigations in the last years unravelled the existence of two novel physical effects that speed up the magnetophoresis kinetics and explain the observed feasibility of LGMS. Those two effects are (i) cooperative magnetophoresis (due to the cooperative motion of strongly interacting particles) and (ii) magnetophoresis-induced convection (fluid dynamics instability originating from inhomogeneous magnetic gradients). In this feature article, we present a unified view of magnetophoresis based on the extensive research done on these effects. We present the physical basis of each effect and also propose a classification of magnetophoresis into four distinct regimes. This classification is based on the range of values of two dimensionless quantities, namely, aggregation parameter N* and magnetic Grashof number Gr m, which include all of the dependency of LGMS on various physical parameters (such as particle properties, thermodynamic parameters, fluid properties, and magnetic field properties). This analysis provides a holistic view of the classification of transport mechanisms in LGMS, which could be particularly useful in the design of magnetic separators for engineering applications.

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Section: ■ Fundamental Conceptsmentioning

confidence: 99%

Unified View of Magnetic Nanoparticle Separation under Magnetophoresis

et al. 2020

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“…It has been shown that magnetic nanoparticles and magnetic fields may induce destructive heat against the targeted cells, inducing apoptosis and cell death. , Besides, magnetic nanoparticles can internalize inside the targeted cells, allowing the combined therapeutic agents to precisely exert the need for intercellular activity . It is also highly possible that the magnetic force can direct the particles to biofilms’ core, resulting in severe physical damage to the bacterial colonies. , For that, we examined the effect of the microemulsion containing the SPIONs without the photosensitizer under the magnetic field force (Figure B). We found that using microemulsions containing only SPIONs under the magnetic field resulted in around 1-log reduction, which is considered a minor reduction when evaluating the antibacterial properties of dental products.…”

Section: Resultsmentioning

confidence: 99%

“…58 It is also highly possible that the magnetic force can direct the particles to biofilms' core, resulting in severe physical damage to the bacterial colonies. 17,59 For that, we examined the effect of the microemulsion containing the SPIONs without the photosensitizer under the magnetic field force (Figure 5B). We found that using microemulsions containing only SPIONs under the magnetic field resulted in around 1-log reduction, which is considered a minor reduction when evaluating the antibacterial properties of dental products.…”

Section: Resultsmentioning

confidence: 99%

Magnetic-Responsive Photosensitizer Nanoplatform for Optimized Inactivation of Dental Caries-Related Biofilms: Technology Development and Proof of Principle

et al. 2021

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Conventional antibiotic therapies for biofilm-trigged oral diseases are becoming less efficient due to the emergence of antibiotic-resistant bacterial strains. Antimicrobial photodynamic therapy (aPDT) is hampered by restricted access to bacterial communities embedded within the dense extracellular matrix of mature biofilms. Herein, a versatile photosensitizer nanoplatform (named MagTBO) was designed to overcome this obstacle by integrating toluidine-blue ortho (TBO) photosensitizer and superparamagnetic iron oxide nanoparticles (SPIONs) via a microemulsion method. In this study, we reported the preparation, characterization, and application of MagTBO for aPDT. In the presence of an external magnetic field, the MagTBO microemulsion can be driven and penetrate deep sites inside the biofilms, resulting in an improved photodynamic disinfection effect compared to using TBO alone. Besides, the obtained MagTBO microemulsions revealed excellent water solubility and stability over time, enhanced the aPDT performance against S. mutans and saliva-derived multispecies biofilms, and improved the TBO’s biocompatibility. Such results demonstrate a proof-of-principle for using microemulsion as a delivery vehicle and magnetic field as a navigation approach to intensify the antibacterial action of currently available photosensitizers, leading to efficient modulation of pathogenic oral biofilms.

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“…Moreover, microbead‐based assays have several advantages, such as no washing steps compare to conventional flat microarray, multiplexed assay using an encoded microbead, amplified signal and short assay time because of the freely moveable microbeads in mediums [101,102]. Due to these considerations, various other techniques have been employed to form magnetically responsive bead of all types by using nanoparticles as the main building blocks [32,103,104].…”

Section: Design Criteria Of Magnetophoretic Systemmentioning

confidence: 99%

“…employed to form magnetically responsive bead of all types by using nanoparticles as the main building blocks [32,103,104].…”

Section: Particle Designmentioning

confidence: 99%

Design and operation of magnetophoretic systems at microscale: Device and particle approaches

2021

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Combining both device and particle designs are the essential concepts to be considered in magnetophoretic system development. Researcher efforts are often dedicated to only one of these design aspects and neglecting the interplay between them. Herein, to bring out importance of the idea of integration between device and particle, we reviewed the working principle of magnetophoretic system (includes both device and particle design concepts). Since, the magnetophoretic force is influenced by both field gradient and magnetization volume, hence, accurate prediction of the magnetophoretic force is relying on the availability of information on both parameters. In device design, we focus on the different strategies used to create localized high‐field gradient. For particle design, we emphasize on the scaling between hydrodynamic size and magnetization volume. Moreover, we also briefly discussed the importance of magnetoshape anisotropy related to particle design aspect of magnetophoretic systems. Next, we illustrated the need for integration between device and particle design using microscale applications of magnetophoretic systems, include magnetic tweezers and microfluidic systems, as our working example. On the basis of our discussion, we highlighted several promising examples of microscale magnetophoretic systems which greatly utilized the interplay between device and particle design. Further, we concluded the review with several factors that possibly resulted in the lack of research efforts related to device and particle design integration.

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Sedimentation Kinetics of Magnetic Nanoparticle Clusters: Iron Oxide Nanospheres vs Nanorods

Cited by 17 publications

References 47 publications

Unified View of Magnetic Nanoparticle Separation under Magnetophoresis

Unified View of Magnetic Nanoparticle Separation under Magnetophoresis

Magnetic-Responsive Photosensitizer Nanoplatform for Optimized Inactivation of Dental Caries-Related Biofilms: Technology Development and Proof of Principle

Design and operation of magnetophoretic systems at microscale: Device and particle approaches

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