Interaction of water vapor with the surfaces of imidazolium-based ionic liquid nanoparticles and thin films.

Understanding the interactions of humid air with ionic liquids (ILs) is critical for predicting how their physicochemical properties are affected by water. Using experimental and theoretical techniques, water vapor's interaction with aerosolized nanoparticles and thin films of [C(2)MIM][Cl] and [C(2)MIM][BF(4)] was studied. Solutions were electrosprayed to produce dry particles.

Enhanced thermoelectric metrics in ultra-long electrodeposited PEDOT nanowires.

The Seebeck coefficient, S, and the electrical conductivity, σ, of electrodeposited poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires and thin films are reported. PEDOT nanowires were prepared by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) in aqueous LiClO(4) within a template prepared using the lithographically patterned nanowire electrodeposition (LPNE) process. These nanowires were 40-90 nm in thickness, 150-580 nm in width, and 200 μm in length.

Virus-PEDOT nanowires for biosensing.

The separate fields of conducting polymer-based electrochemical sensors and virus-based molecular recognition offer numerous advantages for biosensing. Grafting M13 bacteriophage into an array of poly (3,4-ethylenedioxythiophene) (PEDOT) nanowires generated hybrids of conducting polymers and viruses. The virus incorporation into the polymeric backbone of PEDOT occurs during electropolymerization via lithographically patterned nanowire electrodeposition.

Single-molecule imaging of platinum ligand exchange reaction reveals reactivity distribution.

Single-molecule fluorescence microscopy provided information about the real-time distribution of chemical reactivity on silicon oxide supports at the solution-surface interface, at a level of detail which would be unavailable from a traditional ensemble technique or from a technique that imaged the static physical properties of the surface. Chemical reactions on the surface were found to be uncorrelated; that is, the chemical reaction of one metal complex did not influence the location of a future chemical reaction of another metal complex.

Reaction of bromide with bromate in thin-film water.

Thin-film water is ubiquitous in nature, occurring on virtually all surfaces exposed to the ambient environment. In particular, alkali halide salts below their deliquescence point are expected to be coated with water films from one molecular layer to a few nanometers thick. While salt ion mobility in thin-film water has been characterized in the literature, little is known about the chemistry occurring within these films.

Hygroscopic growth and deliquescence of NaCl nanoparticles mixed with surfactant SDS.

Several complementary experimental and theoretical methodologies were used to explore water uptake on sodium chloride (NaCl) particles containing varying amounts of sodium dodecyl sulfate (SDS) to elucidate the interaction of water with well-defined, environmentally relevant surfaces. Experiments probed the hygroscopic growth of mixed SDS/NaCl nanoparticles that were generated by electrospraying aqueous 2 g/L solutions containing SDS and NaCl with relative NaCl/SDS weight fractions of 0, 5, 11, 23, or 50 wt/wt %. Particles with mobility-equivalent diameters of 14.

Halide vacancies created by the heterogeneous reaction of OH with alkali halide single crystals.

The heterogeneous surface reaction of OH with dry KI(100) results in iodide vacancies in the surface lattice sites that are filled with OH to generate a stable layer of KOH. Under high-vacuum conditions, in which surface ions are not mobile, the reaction is self-passivating and generates two molecular layers of potassium hydroxide, releasing 1.6 x 10(16) iodide ions per cm(2) of surface area.

Experimental and theoretical characterization of adsorbed water on self-assembled monolayers: understanding the interaction of water with atmospherically relevant surfaces.

A combination of experiments and molecular dynamic (MD) simulations has been applied to elucidate the nature of water on organic self-assembled monolayers (SAMs) before and after oxidation. SAMs mimic organics adsorbed on environmental urban surfaces. Water on clean or SAM-coated borosilicate glass surfaces was measured at equilibrium as a function of relative humidity (RH), using transmission Fourier transform infrared (FTIR) spectroscopy at 1 atm and 22 +/- 1 degrees C.

Direct electrical transduction of antibody binding to a covalent virus layer using electrochemical impedance.

Electrochemical impedance spectroscopy is used to detect the binding of a 148.2 kDa antibody to a "covalent virus layer" (CVL) immobilized on a gold electrode. The CVL consisted of M13 phage particles covalently anchored to a 3 mm diameter gold disk electrode.

Covalent virus layer for mass-based biosensing.

M13 virus particles were covalently attached to a planar gold-coated quartz crystal microbalance (QCM) through reaction with a self-assembled monolayer of N-hydroxysuccinimide thioctic ester, followed by incorporation of the blocking agent bovine serum albumin. This immobilization chemistry produced a phage multilayer having a coverage equivalent to approximately 6.5 close-packed monolayers of the virus.

Substrate changes associated with the chemistry of self-assembled monolayers on silicon.

Alkylsiloxane self-assembled monolayers (SAMs) are used in the semiconductor industry and, more recently, as proxies for organics adsorbed on airborne mineral dust and on buildings and construction materials. A number of methods have been used for removing the SAM from the substrate after reaction or use, particularly plasmas or piranha (H2SO4/H2O2) solution. However, when the substrates are reused to make new SAMs, the impact of the cleaning methods on the chemistry of subsequently formed SAMs on the surface is not known.

Virus electrodes for universal biodetection.

A dense virus layer, readily tailored for recognition of essentially any biomarker, was covalently attached to a gold electrode surface through a self-assembled monolayer. The resistance of this "virus electrode", Z(Re), measured in the frequency range from 2 to 500 kHz in a salt-based pH 7.2 buffer, increased when the phage particles selectively bound either an antibody or prostate-specific membrane antigen (PSMA), a biomarker for prostate cancer.

Unusual aggregates from the oxidation of alkene self-assembled monolayers: a previously unrecognized mechanism for SAM ozonolysis?

Self-assembled monolayers (SAMs) of vinyl-terminated 3- and 8-carbon compounds were generated on Si substrates and reacted at room temperature with approximately 1 ppm gaseous O(3). A combination of atomic force microscopy (AFM), scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to study the surface composition and morphology after oxidation. A distribution of large ( approximately 0.

Atomic force microscopy of a hybrid high-molecular-weight glutenin subunit from a transgenic hexaploid wheat.

The high-molecular-weight glutenin subunits (HMW-GS) of wheat gluten in their native form are incorporated into an intermolecularly disulfide-linked, polymeric system that gives rise to the elasticity of wheat flour doughs. These protein subunits range in molecular weight from about 70 K-90 K and are made up of small N-terminal and C-terminal domains and a large central domain that consists of repeating sequences rich in glutamine, proline, and glycine. The cysteines involved in forming intra- and intermolecular disulfide bonds are found in, or close to, the N- and C-terminal domains.

Permeabilization of lipid bilayers is a common conformation-dependent activity of soluble amyloid oligomers in protein misfolding diseases.

Amyloid fibrillization is multistep process involving soluble oligomeric intermediates, including spherical oligomers and protofibrils. Amyloid oligomers have a common, generic structure, and they are intrinsically toxic to cells, even when formed from non-disease related proteins, which implies they also share a common mechanism of pathogenesis and toxicity. Here we report that soluble oligomers from several types of amyloids specifically increase lipid bilayer conductance regardless of the sequence, while fibrils and soluble low molecular weight species have no effect.

Modular domain structure: a biomimetic strategy for advanced polymeric materials.

A long lasting challenge in polymer science is to design polymers that combine desired mechanical properties such as tensile strength, fracture toughness, and elasticity into one structure. A novel biomimetic modular polymer design is reported here to address this challenge. Following the molecular mechanism used in nature, modular polymers containing multiple loops were constructed by using precise and strong hydrogen bonding units.

Common structure of soluble amyloid oligomers implies common mechanism of pathogenesis.

Soluble oligomers are common to most amyloids and may represent the primary toxic species of amyloids, like the Abeta peptide in Alzheimer's disease (AD). Here we show that all of the soluble oligomers tested display a common conformation-dependent structure that is unique to soluble oligomers regardless of sequence. The in vitro toxicity of soluble oligomers is inhibited by oligomer-specific antibody.