Trapping Single Molecules by Dielectrophoresis

Hölzel, Ralph; Calander, Nils; Chiragwandi, Zackary; Willander, Magnus; Bier, Frank F.

doi:10.1103/physrevlett.95.128102

Cited by 184 publications

(187 citation statements)

References 33 publications

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“…By reducing the gap between the electrodes to 0.5 μm and applying a 10 V rms signal, a value for (E.∇)E of 10 21 V 2 /m 3 is achieved, as shown in Fig. 8b, enabling Hölzel et al 28 to capture single protein molecules at the electrode tips by positive DEP. These examples should be borne in mind when considering the various electrode materials and geometries adopted by others, as outlined by Hughes 17 and Perez-Gonzalez et al 42 in their reviews.…”

Section: Generating the Dep Forcementioning

confidence: 99%

Review—Where Is Dielectrophoresis (DEP) Going?

Pethig

2016

J. Electrochem. Soc.

134

104

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A guide is offered to new researchers (and their supervisors) of the most promising topics to explore in market-driven or curiositydriven dielectrophoresis (DEP) research. Based on an analysis of publications since 2000, contributions from electronic engineers and materials scientists are likely to be maintained, with increasing emphasis on the development of DEP-based protocols for chemical and biochemical analyses that involve nanoparticles. Two modes of DEP are likely to dominate, namely metal-electrode based (eDEP) and insulator-based (iDEP). Where high values of the electric field and its gradient are required, such as the spatial manipulation of nanoparticles (e.g., exosomes, proteins, viruses, carbon-nanotubes), eDEP would in many cases be the preferred choice. This would also be the case for the selective isolation of biological cells; the development of cell-based drug discovery protocols; electronic sensors and the assembly of nanoparticles (e.g., carbon nanotubes). Applications of iDEP would be particularly suited for the separation or detection of bioparticles such as DNA, RNA, proteins or bacteria, where manipulation selectivity is based on differences in surface charge. Hot topics include the development of dynamic patterning of bioparticles using photoconductive electrodes, and the genome-wide mapping between genotype and DEP phenotype of cells. The motivation for conducting this analysis came from email exchanges with postgraduates commencing projects involving the electrokinetic manipulation of particles, as well as from discussions with business people and venture capitalists. Apart from seeking advice on specific technical issues, opinions were sought by postgrads regarding the "hottest' topics for investigation and the potential for long-term careers in the subject. For the more commercially minded with inbuilt risk aversion, it was appropriate to explain that dielectrophoresis (DEP) was the term coined by Herbert Pohl as far back as 1951 to describe the translational motion of an electrically polarized particle in a non-uniform electric field.1 Such interested parties also required assurances that the maturity of the technology presents low risk of failure to meet technical objectives. This can be approached by explaining that the phenomenon has been exploited since 1924 (for the separation of minerals 2 ), with a theoretical basis to be found in early 19th century text books. 3 Furthermore, various aspects of the subject are treated in text books 4-9 and review articles 10-17 that take us to the present status of DEP technology. Responses to these intended reassurances are invariably of the form: "If DEP has been around for so long and is considered such an innovative technology, why hasn't it received significant commercial exploitation?" Although this assessment may be uncomfortable to receive, the so-called Golden Rule (i.e., he who has the gold, rules) should be acknowledged.At least six commercial products incorporating DEP can be cited. For example, the Panasonic bacteria counter dete...

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Section: Generating the Dep Forcementioning

confidence: 99%

Review—Where Is Dielectrophoresis (DEP) Going?

Pethig

2016

J. Electrochem. Soc.

134

104

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“…Many of these techniques are relatively time consuming, costly and often lead to significant loss of the analyte. AC electrokinetic techniques, like dielectrophoresis (DEP) have been attractive because they allow cells [9][10][11], hmw-DNA biomarkers [12][13][14][15] and proteins [16] to be rapidly isolated and concentrated into specific microscopic locations. Dielectrophoresis (DEP) is an induced motion of particles produced by the dielectric differences between the particles and media in an AC electric field [17,18].…”

Section: Introductionmentioning

confidence: 99%

An AC electrokinetic method for enhanced detection of DNA nanoparticles

Krishnan

Heller

2009

Journal of Biophotonics

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Journal of BIOPHOTONICSIn biomedical research and diagnostics it is a challenge to isolate and detect low levels of nanoparticles and nanoscale biomarkers in blood and other biological samples. While highly sensitive epifluorescent microscope systems are available for ultra low level detection, the isolation of the specific entities from large sample volumes is often the bigger limitation. AC electrokinetic techniques like dielectrophoresis (DEP) offer an attractive mechanism for specifically concentrating nanoparticles into microscopic locations. Unfortunately, DEP requires significant sample dilution thus making the technology unsuitable for biological applications. Using a microelectrode array device, special conditions have been found for the separation of hmw-DNA and nanoparticles under high conductance (ionic strength) conditions. At AC frequencies in the 3000-10 000 Hz range, 10 mm microspheres and human T lymphocytes can be isolated into the DEP low field regions, while hmw-DNA and nanoparticles can be concentrated into microscopic high field regions for subsequent detection using an epifluorescent system.Final separation and detection of 150 ng/mL OliGreen fluorescent stained high molecular weight (hmw) DNA in 1 Â TBE buffer (109 mS/m). The DEP field was applied at 10 000 Hz and 10 volts pk-pk for 5 minutes to group of nine microelectrodes. The green fluorescent image (Ex 505 nm, Em 520 nm) shows fluorescence from the OliGreen stained hmw DNA concentrated on the 80-micron diameter microelectrodes with the far right column of unactivated microelectrodes showing no concentration of hmw-DNA.

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“…DEP is defined as the translational motion of particles caused by an inhomogeneous electric field (14) and has been previously used for particle manipulation (16)(17)(18)(19)(20), particle/cell separation (21-26), and particle assembly/trapping. (17,19,(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38) Electrically driven particle motion depends on the dielectric constant contrast between the solvent and the particle. A particle with a dielectric constant (« p ) different from the suspending medium (« m ) acquires a dipole moment under the influence of an electric field and is either attracted toward (if « p > « m , "positive" DEP), or repelled from (if « p < « m , "negative" DEP) the regions with the strongest electric field.…”

Section: Resultsmentioning

confidence: 99%

Periodically microstructured composite films made by electric- and magnetic-directed colloidal assembly

Demirörs

Courty

Libanori

et al. 2016

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

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Living organisms often combine soft and hard anisotropic building blocks to fabricate composite materials with complex microstructures and outstanding mechanical properties. An optimum design and assembly of the anisotropic components reinforces the material in specific directions and sites to best accommodate multidirectional external loads. Here, we fabricate composite films with periodic modulation of the soft-hard microstructure by simultaneously using electric and magnetic fields. We exploit forefront directed-assembly approaches to realize highly demanded material microstructural designs and showcase a unique example of how one can bridge colloidal sciences and composite technology to fabricate next-generation advanced structural materials. In the proof-of-concept experiments, electric fields are used to dictate the position of the anisotropic particles through dielectrophoresis, whereas a rotating magnetic field is used to control the orientation of the particles. By using such unprecedented control over the colloidal assembly process, we managed to fabricate ordered composite microstructures with up to 2.3-fold enhancement in wear resistance and unusual site-specific hardness that can be locally modulated by a factor of up to 2.5.L ightweight composites offer an attractive alternative toward minimization of the energy demand of mobility systems from automobiles and airplanes to trains and ships. Continuous stiff fibers or discontinuous anisotropic particles have often been used as reinforcing phase to enhance the specific mechanical properties of such lightweight polymer-based composites. Although the fabrication costs of long-fiber reinforced composites remain prohibitive for the large-scale production of high-performance materials, the processing of polymer-based composites reinforced with discontinuous stiff elements can often be adapted to the automated manufacturing processes commonly used in the polymer industry, such as injection molding. However, these fabrication processes usually offer a limited control over the alignment and spatial distribution of the reinforcing particles, preventing a full optimization of the microstructural design in composite materials. Thus, the development of new strategies to assemble microstructured composites with tailored reinforcing architectures is crucial for the design and fabrication of even lighter and cheaper structural materials.Control over the spatial distribution and orientation of particles in composites can be achieved using colloidal assembly tools that guide/template the organization of the reinforcing particles while the material is still in a fluid state. Recently, we have shown that control of particle orientation using an external magnetic field can lead to a significant increase in the materials' resistance against deformation, wear, and crack initiation, widening their range of applications (1, 2). Independent of orientation control, tuning the spatial distribution of particles through magnetic fields, centrifugal forces, or film welding techniq...

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Trapping Single Molecules by Dielectrophoresis

Cited by 184 publications

References 33 publications

Review—Where Is Dielectrophoresis (DEP) Going?

Review—Where Is Dielectrophoresis (DEP) Going?

An AC electrokinetic method for enhanced detection of DNA nanoparticles

Periodically microstructured composite films made by electric- and magnetic-directed colloidal assembly

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