Stability of polymethyl methacrylate latex dispersions prepared by using mixtures of anionic and nonionic surfactants

Ono, Hiroshi; Jidai, E.

doi:10.1007/bf01526736

Cited by 1 publication

(1 citation statement)

References 17 publications

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“…The most critical aspect of assembling the fluid cell for magnetic or DEP tweezers is designing appropriate surface and solution chemistry that allows the bead to bind to the DNA but not the substrate. − A typical force–distance profile of a probe approaching a surface can be described by an extended Derjaguin and Landau, Verwey and Overbeek (DLVO) theory that treats the overall interaction of a particle and a surface as the sum of the electrostatic, van der Waals, and steric forces. − The combination of the repulsive forces (steric and electrostatic), which decay exponentially with separation, and attractive forces (van der Waals), which decreases as an inverse square function of separation, creates a distinct set of force distance profiles (Figure ). These forces compete with each other and either push the probe away from the surface or pull the probe into contact with the surface.…”

Section: Approachmentioning

confidence: 99%

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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