Micromixing with Linked Chains of Paramagnetic Particles

Biswal, Sibani Lisa; Gast, Alice P.

doi:10.1021/ac0494580

Cited by 165 publications

(147 citation statements)

References 25 publications

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“…Indeed, the degradation of 4-nitrophenol and methylene blue proceeds considerably faster in the microdroplets than in the conventional container under the same magnetic field conditions. This is in concordance with the results obtained with composite microstirrers, which were demonstrated to efficiently enhance the catalysis of diverse types of reactions in microdroplet conditions [32,33].…”

Section: Role Of the Reaction Geometrysupporting

confidence: 90%

Magnetically-actuated mesoporous nanowires for enhanced heterogeneous catalysis

Serrà

Grau

Gimbert‐Suriñach

et al. 2017

Applied Catalysis B: Environmental

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We study the optimization of the catalytic properties of entirely magnetic CoPt compact and mesoporous nanowires of different diameters (25 -200 nm) by using magnetic actuation. The nanowires are a single-entity, robust, magnetic-catalyst with a huge catalytically-active surface area.We show that apart from conventional parameters, like the size and morphology of the nanowires, other 2 factors can be optimized to enhance their catalytic activity. In particular, given the magnetic character of the nanowires, rotating magnetic fields are a very powerful approach to boost the performance of the catalyst. In particular, the magnetic field induces them to act as nano-stirrers, improving the local flow of material towards the active sites of the catalyst. We demonstrate the versatility of the procedure by optimizing (i) the degradation of different types of pollutants (4-nitrophenol and methylene blue) and (ii) hydrogen production. For example, by using as little as 0.1 mg mL -1 of 25 nm wide CoPt mesoporous nanowires (with 3 nm pore size) as catalysts, kinetic normalized constants knor as high as 20667 and 21750 s -1 g -1 for 4-nitrophenol and methylene blue reduction, respectively, are obtained. In addition, activity values for hydrogen production from borohydride are as high as 25.0 L H2 g -1 min -1 , even at room temperature. These values outperform any current state-of-the-art proposed catalysis strategies for water remediation reactions by at least 10-times and are superior to most advanced approaches to generate hydrogen from borohydride. The recyclability of the nanowires together with the simplicity of the synthetic method makes this approach (using not only CoPt, but also other mesoporous magnetic catalysts) very appealing for very diverse types of catalytic applications. Graphical AbstractHighlights  Magnetic actuation of purely magnetic mesoporous nanowires (NWs) is revealed as a novel and efficient catalysis procedure in reactions of heterogeneous catalysis in environmental and energy fields. Mesoporous CoPt NWs are simultaneously effective catalysts itself and the stirring device, using magnetic fields, to catalyse reactions in solution. The procedure allows ultra-fast degradation of different types of pollutants. 3 The NWs show very high effectivity for hydrogen generation (25.0 L H2 g -1 min -1 ) by catalysing the hydrolysis of sodium borohydride using magnetic actuation.

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Section: Role Of the Reaction Geometrysupporting

confidence: 90%

Magnetically-actuated mesoporous nanowires for enhanced heterogeneous catalysis

Serrà

Grau

Gimbert‐Suriñach

et al. 2017

Applied Catalysis B: Environmental

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“…Superparamagnetic (SPM) beads have proven to be a highly efficient materials for separating proteins, nucleic acids, viruses, and cells, due to the high surface area, and the high rate of 20 separation and mass transfer that takes place in highly concentrated suspensions of micron size beads. [1][2][3][4][5] For example, antibody and glass functionalized SPM beads are now widely used for the isolation of specific cell types and nucleic acids, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…5,[17][18][19][20][21] This has limited HGM to dilute solutions in which bead-bead interaction are unlikely to occur. FEM calculations of the local magnetic field on the MMAs, as shown in Figure 1B, revealed that the SPM beads produce little change in the local magnetic field and thus the SPM beads do not interact with each other to 5 form chains.…”

Section: Introductionmentioning

confidence: 99%

Flow enhanced non-linear magnetophoretic separation of beads based on magnetic susceptibility

Kilinc

Ran

et al. 2013

Lab Chip

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Magnetic separation provides a rapid and efficient means of isolating biomaterials from complex mixtures based on their adsorption on superparamagnetic (SPM) beads. Flow enhanced non-linear magnetophoresis (FNLM) is a high-resolution mode of separation in which hydrodynamic and magnetic fields are controlled with micron resolution to isolate SPM beads with specific physical properties. In this article we demonstrate that a change in the critical frequency of FNLM can be used to identify beads with 10 magnetic susceptibilities between 0.01 and 1.0 with a sensitivity of 0.01 Hz -1 . We derived an analytical expression for the critical frequency that explicitly incorporates the magnetic and non-magnetic composition of a complex to be separated. This expression was then applied to two cases involving the detection and separation of biological targets. This study defines the operating principles of FNLM and highlights the potential for using this technique for multiplexing diagnostic assays and isolating rare cell 15 types.

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“…Of important note is the assembly process is a reversible one; as the field is switched off, the clusters will disassemble, turning off device function if desired. One significant advantage of the colloids we use here is that they are readily available with a variety of surface functionalities, including reactive groups that can be used for irreversible assembly binding (19) if continued device operation is useful after field switch-off. And although only 2 of these valves are shown, their construction could be performed in a parallel fashion because of the global nature of the driving field.…”

Section: Resultsmentioning

confidence: 99%

In situ assembly of linked geometrically coupled microdevices

Sawetzki

Rahmouni

Bechinger

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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Complex systems require their distinct components to function in a dynamic, integrated, and cooperative fashion. To accomplish this in current microfluidic networks, individual valves are often switched and pumps separately powered by using macroscopic methods such as applied external pressure. Direct manipulation and control at the single-device level, however, limits scalability, restricts portability, and hinders the development of massively parallel architectures that would take best advantage of microscale systems. In this article, we demonstrate that local geometry combined with a simple global field can not only reversibly drive component assembly but also power distinct devices in a parallel, locally uncoupled, and integrated fashion. By employing this single approach, we assemble and demonstrate the operation of check valves, mixers, and pistons within specially designed microfluidic environments. In addition, we show that by linking these individual components together, more complex devices such as pumps can be both fabricated and powered in situ.colloids ͉ microfluidics ͉ micromachines

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Micromixing with Linked Chains of Paramagnetic Particles

Cited by 165 publications

References 25 publications

Magnetically-actuated mesoporous nanowires for enhanced heterogeneous catalysis

Magnetically-actuated mesoporous nanowires for enhanced heterogeneous catalysis

Flow enhanced non-linear magnetophoretic separation of beads based on magnetic susceptibility

In situ assembly of linked geometrically coupled microdevices

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