Abstract: A flexible chemiresistor (CR) sensor for sensing a molecule of interest in a fluid (liquid or gas) is provided. The flexible CR sensor comprises a flexible chemiresistor (CR) module. The flexible CR module comprises a flexible substrate such polyethylene terephthalate (PET), polyethylene naphthalate (PEN) or polyimide (PI), and a thin film nanoparticle assembly assembled on the flexible substrate. The thin film nanoparticle assembly comprises metal or metal alloy core, ligand-capped nanoparticles and molecular linkers connecting the nanoparticles. The flexible CR sensor and an intelligent pattern recognition engine can be incorporated in a handheld device that can detect a molecule of interest in a fluid (e.g., a liquid or gas) accurately, rapidly, and without false positives. Any sensing array nanomaterial, pattern recognition, and compact/or electronic hardware can be integrated to achieve a desired detection limit and response speed.

Abstract: Synthesis of nanoparticles with particle size control is provided by the method of using two different metal-containing precursors, a capping component, an optional reducing agent, and then contacting the two precursors with the capping component to form a reaction solution, which is heated to produce first and second metals-containing nanoparticles. By controlling the ratio of the concentration of the capping component to the total concentration of the two metal-containing precursors, the nanoparticles can have diameters ranging between about 1 nm to about 15 nm. A decrease in the concentration of the capping component typically increases the size of the nanoparticles. Preferred compositions include Pt and Co-containing alloy nanoparticles. Controlled synthesis of larger, about 6 nm to about 12 nm, sized nanoparticles can be achieved in a solvent-free reaction process.

Abstract: The present invention is directed to an aggregate composed of a plurality of nanoparticles of a transition metal and a plurality of cyanine dye molecules that are interacting non-covalently. The nanoparticles are capped with a capping molecule, while the cyanine dye molecule can be cationic, anionic, or neutral cyanine dye. Methods of making such aggregates and for using them in detection of an analyte are also disclosed.

Abstract: A method of forming mono-disperse iron-oxide core metal shell nanoparticles is disclosed. Particle size of the oxide core seeds is controlled and capped seeds are formed. The capping layer is desorbed by a thermally activated process and metal such as gold is chemically deposited on the core seeds in situ. This process can be repeated to produce multi-metal or different metal shells. A second capping layer is applied on the core/shell composite nanoparticles. In another step, the particles are sized by centrifuging to obtain a tightly controlled and narrow particle size distribution. The water-dispersibility of the particles is achieved by a thiol exchange reaction on the gold shell of the core/shell nanoparticles or by deposition of gold on ferritin-derived iron oxide cores in aqueous solution. Mono and multilayer thin films are assembled on different substrates using the core/shell particles and linking molecules.

Abstract: A method of preparing carbon-loaded, gold-based nanoparticle catalysts useful as anode catalysts for the electrocatalytic methanol oxidation reaction (MOR) as well as the oxygen reduction reaction (ORR). AumPtnM100-m-n catalysts may be prepared by either a two-phase protocol or by a thermal decomposition/reduction protocol. The prepared nanoparticles having different bimetallic ratios are assembled on carbon black support materials and activated by thermal treatment. This approach provides good control of nanoparticle size, composition and/or surface properties. Electrocatalytic MOR activities of the prepared and activated AuPt nanoparticle provided in accordance with the methods of the invention are present in both acidic and alkaline electrolytes.

Abstract: Synthesis of nanoparticles with particle size control is provided by the method of using two different metal-containing precursors, a capping component, an optional reducing agent, and then contacting the two precursors with the capping component to form a reaction solution, which is heated to produce first and second metals-containing nanoparticles. By controlling the ratio of the concentration of the capping component to the total concentration of the two metal-containing precursors, the nanoparticles can have diameters ranging between about 1 nm to about 15 nm. A decrease in the concentration of the capping component typically increases the size of the nanoparticles. Preferred compositions include Pt and Co-containing alloy nanoparticles. Controlled synthesis of larger, about 6 nm to about 12 nm, sized nanoparticles can be achieved in a solvent-free reaction process.

Abstract: A method of synthesizing highly monodispersed Au nanoparticles having diameters in the range of 30-90 nm. Seed nanoparticles in a controlled concentration are combined with a precursor, also in a controlled concentration, a reducing and capping agent (e.g., sodium acrylate) in aqueous solution. Under controlled conditions of pH, temperature, and time, highly monodispersed nanoparticles having diameters in the range of 30-100 nm are produced. A relative size standard deviation of the size distribution of the resulting nanoparticles is as low as 2%.

Abstract: The present invention is directed toward a multi-moduled nanoparticle-structured sensing array and pattern recognition device for detection of acetone in breath.

Abstract: The present invention is directed to an aggregate composed of a plurality of nanoparticles of a transition metal and a plurality of cyanine dye molecules that are interacting non-covalently. The nanoparticles are capped with a capping molecule, while the cyanine dye molecule can be cationic, anionic, or neutral cyanine dye. Methods of making such aggregates and for using them in detection of an analyte are also disclosed.

Abstract: The present invention is directed toward oxidation-resistant, ligand-capped nanoparticles, each comprising one or more capping ligands on a copper-containing core. Methods of making and using these nanoparticles are also disclosed.

Abstract: The present invention is directed toward core-shell nanoparticles, each comprising a ligand-capped metal shell surrounding a plurality of discrete, nonconcentric, metal-containing cores. Methods of making and using these nanoparticles are also disclosed.

Abstract: The present teachings are directed toward single metal and alloy nanoparticles and synthesis methods for preparing single metal and alloy nanoparticles.

Abstract: A method of synthesizing highly monodispersed Au nanoparticles having diameters in the range of 30-90 nm. Seed nanoparticles in a controlled concentration are combined with a precursor, also in a controlled concentration, a reducing and capping agent (e.g., sodium acrylate) in aqueous solution. Under controlled conditions of pH, temperature, and time, highly monodispersed nanoparticles having diameters in the range of 30-100 nm are produced. A relative size standard deviation of the size distribution of the resulting nanoparticles is as low as 2%.

Abstract: A method is featured for fabricating Carbon-supported AuPt nanoparticle catalysts for fuel cells, and particularly fuel cells using methanol as the fuel. The method prepares AuPt-based fuel cell catalysts having a wide range of controllable Au:Pt ratios. The AuPt catalysis are supportable on both carbon black (C) and C/TiO2 support materials. These materials demonstrate electro-catalytic activity towards CO and methanol oxidation, and O2 reduction. The same catalyst material is useful in constructing both anodes and cathodes, and demonstrates bifunctional activity.

Abstract: A method is featured for fabricating Carbon-supported AuPt nanoparticle catalysts for fuel cells, and particularly fuel cells using methanol as the fuel. The method prepares AuPt-based fuel cell catalysts having a wide range of controllable Au:Pt ratios. The AuPt catalysis are supportable on both carbon black (C) and C/TiO2 support materials. These materials demonstrate electro-catalytic activity towards CO and methanol oxidation, and O2 reduction. The same catalyst material is useful in constructing both anodes and cathodes, and demonstrates bifunctional activity.

Abstract: There is provided a method of preparing carbon supported, ternary alloy composition core-shell PtVFe nanoparticles for use as fuel cell electrocatalysts. These catalysts have been found particularly useful for oxygen reduction reactions. The alloy nanoparticles can be assembled on carbon supports which then may undergo subsequent activation and/or calcination treatments. The method, combined with new synthetic feed and processing conditions, provides core-shell PtVFe alloy nanoparticles of 1–3 nm size. The catalyst-produced high monodispersity, controlled composition are highly dispersed, and have a uniform distribution. Finally, the correlation of the preparation and treatment parameters to the ORR catalytic activities of the prepared nanoparticles is described. The catalysts exhibit ORR in the range of 2 to 4 times more than a standard Pt/carbon catalyst.

Abstract: The present teachings are directed toward single metal and alloy nanoparticles and synthesis methods for preparing single metal and alloy nanoparticles.

Abstract: An electrically-actuated microfluidic device for fluid delivery and pumping is described. The micropumping device is configured as a capillary tube containing immiscible electrolyte liquids that are subjected to an alternating electrical voltage. The electrical voltage causes the boundary between the two liquids to change its surface tension in a way that provides a pumping action. The micropump requires only a few volts and milliwatts in order to operate.

Abstract: A pump for exerting a pumping force on a fluid in an attached conduit, the pump being actuated by a voltage from a power supply, the pump comprising a liquid metal pool, a containment vessel for confining the pool, an inner tubular member in hydraulic contact with the attached conduit and with an open end disposed in the pool to divide a free upper surface of the pool into an actuation surface and a working surface, an electrolyte in contact with the actuation surface, an electrode in contact with the electrolyte, and an electrode in contact with the pool, such that application of a voltage to the electrodes causes a surface tension change in the actuation surface and a resulting height change in the working surface, whereby a pumping action is transferred to the fluid in the attached conduit.

Abstract: Anisotropically conductive solid polymeric complexes are provided of the formula: ##STR1## wherein P.sup.+ is a cationic polymer, such as a quaternary polyamine, and n and m are selected so that the complex is electrically neutral.