Biomedical subjects

Oleg Gang

Publications and source records attributed to Oleg Gang.

5 recordsLinked to original sources

PubMed2006

A simple method for kinetic control of DNA-induced nanoparticle assembly.

A regulation of the kinetic behavior in DNA-based nanosystems is required for emerging applications in sensing, nanodevice assembling, and gene delivery. Here we describe a broadly applicable method for controlling the kinetics of DNA-mediated nanoparticle self-assembly by tailoring the DNA-capping between single-stranded and partially rigid double-stranded designs. An effect of enhanced assembly kinetics was facilitated by the added rigidity which reduced chain entropy while extending crucial linker segments away from the nanoparticle interface where they are known to coordinate.

DNA↗

PubMed2006

Capillary wave fluctuations and intrinsic widths of coupled fluid-fluid interfaces: an x-ray scattering study of a wetting film on bulk liquid.

An x-ray specular reflectivity (XR) and off-specular diffuse scattering (XDS) study of the coupled thermal capillary fluctuations and the intrinsic profiles of two interacting fluid-fluid interfaces is presented. The measurements are carried out on complete wetting films of perfluoromethylcyclohexane (PFMC) on the surface of bulk liquid eicosane (C20), as a function of film thickness 30 infinity), determined by either the radius of gyration (5.3 A) or the bulk correlation length (4.8 A) of the alkane C20. The intrinsic liquid-vapor interfacial width is sharper (approximately 2 A) and remains essentially constant over the entire probed range of D .

Journal Article↗

PubMed2006

High resolution non-contact AFM imaging of liquids condensed onto chemically nanopatterned surfaces.

The wetting of ethanol and octane on chemically nanopatterned surfaces has been investigated using Atomic Force Microscopy (AFM) under controlled environmental conditions. The patterns were generated on a methyl-terminated, organic monolayer using an AFM electro-oxidation process. The subsequent wetting of the organic liquids was studied using non-contact mode AFM under equilibrium conditions with the vapor. This study of condensed nanoliquids provides the first reliable measurements of sub 100 nm liquid profile shapes. The derived contact angles give an estimate of the line tension.

Ethanol↗

PubMed2006

Liquid nanostripes.

Equilibrium wetting of ethanol, a volatile liquid, onto chemically patterned nanostripes has been investigated using noncontact atomic force microscopy (AFM). The chemical patterns, generated by a conducting AFM tip, are composed of COOH terminated "wetting" regions and CH3 terminated "nonwetting" regions. Controlled amounts of ethanol, from the vapor phase, condense on the COOH stripes and their shape is imaged in situ versus their width (70 < w < 300 nm). The measured profile shapes at saturation and their w(1/2) height dependence are well described by density functional theory with dispersive, nonretarded potentials.

Journal Article↗

PubMed2005

Liquids on topologically nanopatterned surfaces.

We report here surface x-ray scattering studies of the adsorption of simple hydrocarbon liquid films on nanostructured surfaces-silicon patterned by an array of nanocavities. Two different regimes, filling and growing, are observed for the wetting film evolution as a function of the chemical potential offset from the bulk liquid-vapor coexistence. The strong influence of geometrical effects is manifested by a dependence of liquid adsorption in the nanocavities that is stronger than the van der Waals behavior for flat surfaces. The observed dependence is, however, much weaker than predicted for the infinitely deep parabolic cavities, suggesting that the finite-size effects contribute significantly to the observed adsorption behavior.

Journal Article↗