Dielectrophoretic tweezers as a platform for molecular force spectroscopy in a highly parallel format

Cheng, Perry; Barrett, Michael J.; Oliver, Piercen M.; Cetin, Deniz; Vezenov, Dmitri V.

doi:10.1039/c1lc20627c

Cited by 22 publications

(24 citation statements)

References 55 publications

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“…Minimal mechanical contact between cells and device structures enables integration of these methods in microfluidic platforms for automated cell sorting and mechanobiological analysis. Electrical forces are used to deform whole individual mammalian cells [162,163], to correlate cell deformability with CSK features [164] and for molecular force spectroscopy [165]. Functionalized beads that are attached to cells permit force coupling through specific molecular binding proteins (e.g.…”

Section: Mesenchymal Stem Cell Heterogeneity and Single Cell Handlingmentioning

confidence: 99%

Mesenchymal stem cell mechanobiology and emerging experimental platforms

MacQueen

Sun

Simmons

2013

J. R. Soc. Interface.

132

103

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Experimental control over progenitor cell lineage specification can be achieved by modulating properties of the cell's microenvironment. These include physical properties of the cell adhesion substrate, such as rigidity, topography and deformation owing to dynamic mechanical forces. Multipotent mesenchymal stem cells (MSCs) generate contractile forces to sense and remodel their extracellular microenvironments and thereby obtain information that directs broad aspects of MSC function, including lineage specification. Various physical factors are important regulators of MSC function, but improved understanding of MSC mechanobiology requires novel experimental platforms. Engineers are bridging this gap by developing tools to control mechanical factors with improved precision and throughput, thereby enabling biological investigation of mechanics-driven MSC function. In this review, we introduce MSC mechanobiology and review emerging cell culture platforms that enable new insights into mechanobiological control of MSCs. Our main goals are to provide engineers and microtechnology developers with an up-to-date description of MSC mechanobiology that is relevant to the design of experimental platforms and to introduce biologists to these emerging platforms.

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Section: Mesenchymal Stem Cell Heterogeneity and Single Cell Handlingmentioning

confidence: 99%

Mesenchymal stem cell mechanobiology and emerging experimental platforms

MacQueen

Sun

Simmons

2013

J. R. Soc. Interface.

132

103

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“…The estimate yields a maximum force of 56 pN, which is also a typical value for this setup. 9 This analysis shows that one can conduct force spectroscopy in a parallel manner using finely tuned system to assemble high density tethered bead arrays.…”

Section: Resultsmentioning

confidence: 98%

“…53,62 The remaining parameters control mainly the magnitude of the force minimum (maximum adhesive force). Since our magnetic/DEP tweezers setup is capable of applying forces of up to 20–40 pN, 3,9 it is important that the maximum adhesion force is below that value under most experimental conditions. Convenient surface chemistry dictated our choice of gold as a substrate for magnetic/DEP tweezers and effectively fixed the value of the Hamaker constant.…”

Section: Resultsmentioning

confidence: 99%

“…The principles of this technique are described in details elsewhere. 9 For an optimized device, one has to confine the probes to the microwell as well as center them. Overall, this setup requires a three-step approach: (i) introduction and positioning of the probes in the microwells, (ii) reaction of the probes with the DNA molecules, and (iii) the actual process of conducting a force spectroscopy experiment.…”

Section: Resultsmentioning

confidence: 99%

“…5–8 Wide field microscopy enables simultaneous observation of multiple force probes. 3,9 The observation of the stretching behavior on such a large sampling scale can give insight into sequence effects in DNA, polyelectrolyte stretching behavior, 10 as well as DNA-protein interactions. 11 …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High Density Single-Molecule-Bead Arrays for Parallel Single Molecule Force Spectroscopy

Barrett¹,

Oliver²,

Cheng³

et al. 2012

Anal. Chem.

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The assembly of a highly-parallel force spectroscopy tool requires careful placement of single-molecule targets on the substrate and the deliberate manipulation of a multitude of force probes. Since the probe must approach the target biomolecule for covalent attachment, while avoiding irreversible adhesion to the substrate, the use of the polymer microsphere as force probes to create the tethered bead array poses a problem. Therefore, the interactions between the force probe and the surface must be repulsive at very short distances (< 5 nm) and attractive at long distances. To achieve this balance, the chemistry of the substrate, force probe, and solution must be tailored to control the probe-surface interactions. In addition to an appropriately designed chemistry, it is necessary to control the surface density of the target molecule in order to ensure that only one molecule is interrogated by a single force probe. We used gold-thiol chemistry to control both the substrate’s surface chemistry and the spacing of the studied molecules, through a competitive binding of the thiol-terminated DNA and an inert thiol forming a blocking layer. For our single molecule array, we modeled the forces between the probe and the substrate using DLVO theory and measured their magnitude and direction with colloidal probe microscopy. The practicality of each system was tested using a probe binding assay to evaluate the proportion of the beads remaining adhered to the surface after application of force. We have translated the results specific for our system to general guiding principles for preparation of tethered bead arrays and demonstrated the ability of this system to produce a high yield of active force spectroscopy probes in a microwell substrate. This study outlines the characteristics of the chemistry needed to create such a force spectroscopy array.

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Progress toward the application of molecular force spectroscopy to DNA sequencing

et al. 2012

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Many recent advances in DNA sequencing have taken advantage of single-molecule techniques using fluorescently-labeled oligonucleotides as the principle mode of detection. However, in spite of the successes of fluorescent-based sequencers, avoidance of labeled nucleotides could substantially reduce the costs of sequencing. This paper discusses the development of an alternative sequencing method in which unlabeled DNA can be manipulated directly on a massively-parallel scale using single-molecule force spectroscopy. We combine a wide-field optical detection technique (evanescent field excitation) with one of two methods of applying force in parallel, magnetic or dielectrophoretic (DEP) tweezers, to attain near single-base sensitivity in the double-stranded character of DNA. This article will discuss the developments of such a single-molecule force spectroscopy technique as a potential technology for genome sequencing.

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Dielectrophoretic tweezers as a platform for molecular force spectroscopy in a highly parallel format

Cited by 22 publications

References 55 publications

Mesenchymal stem cell mechanobiology and emerging experimental platforms

Mesenchymal stem cell mechanobiology and emerging experimental platforms

High Density Single-Molecule-Bead Arrays for Parallel Single Molecule Force Spectroscopy

Progress toward the application of molecular force spectroscopy to DNA sequencing

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