Abstract: The present invention relates to methods of transforming a cell by use of an acoustic transducer. In particular embodiments, the radiofrequency signal to the transducer can be tuned to provide optimal membrane disruption of the cell; and an agent, such as a nucleic acid, can then be delivered to the cell.

Abstract: The present application relates to pulsed discharge ionization detectors (PDIDs) and non-radioactive ionization sources, including miniaturized forms thereof. In some examples, the PDID includes annular electrodes, where each electrode is disposed between annular insulators. Also provided herein are methods of making and using such PDIDs, such as for detecting one or more volatile organic compounds, as well as non-radioactive ionization sources.

Abstract: The present application relates to pulsed discharge ionization detectors (PDIDs) and non-radioactive ionization sources, including miniaturized forms thereof. In some examples, the PDID includes annular electrodes, where each electrode is disposed between annular insulators. Also provided herein are methods of making and using such PDIDs, such as for detecting one or more volatile organic compounds, as well as non-radioactive ionization sources.

Abstract: The present application relates to pulsed discharge ionization detectors (PDIDs) and non-radioactive ionization sources, including miniaturized forms thereof. In some examples, the PDID includes annular electrodes, where each electrode is disposed between annular insulators. Also provided herein are methods of making and using such PDIDs, such as for detecting one or more volatile organic compounds, as well as non-radioactive ionization sources.

Abstract: An aspect of the present disclosure relates to a microsampler for hermetically sealing a sample. In particular, such microsamplers can be useful for encapsulation of chemical, biological, and explosive samples for the purposes of archival sample storage. Methods of making and using such microsamplers are also described herein.

Abstract: The present application relates to microfabricated columns having a sealed flow channel. In particular, the channel is sealed during dicing, thereby preventing debris from accumulating within channels. In use, the seal is ruptured mechanically to connect one or more fluidic connections, which deliver analytes to the flow channel. Additional details are provided for making and using sealed columns.

Abstract: The present invention is directed to devices and methods for detecting one or more markers in a sample. In particular, such devices integrate a plurality of hollow needles configured to extract or obtain a fluid sample from a subject, as well as transducers to detect a marker of interest (e.g., an electrolyte). In some embodiments, the needles are provided as a disposable cartridge.

Abstract: The present invention relates to adhesive-based microvalves, as well as assemblies and cartridges having such microvalves. In particular examples, substantially planar layers of adhesive materials are used to construct both normally-open and normally-closed microvalves for fluid control within microfluidic laminate cartridges. Such microvalves and cartridges can be useful for medical, chemical, and biological investigations.

Abstract: An apparatus that includes a varactor element and an integrated micro-discharge source is disclosed herein. In a general embodiment, the apparatus includes at least one np junction and at least one voltage source that is configured to apply voltage across the np junction. The apparatus further includes an aperture that extends through the np junction. When the voltage is applied across the np junction, gas in the aperture is ionized, forming a plasma, in turn causing a micro-discharge (of light, charge particles, and space charge) to occur. The light (charge particles, and space charge) impinges upon the surface of the np junction exposed in the aperture, thereby altering capacitance of the np junction. When used within an oscillator circuit, the effect of the plasma on the np-junction extends the capacitance changes of the np-junction and extends the oscillator frequency range in ways not possible by a conventional voltage controlled oscillator (VCO).

Abstract: A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

Abstract: A method for measuring a lower heating value of a gaseous fuel. The method includes mixing a gaseous fuel with air to provide a combustible air-fuel mixture. The air-fuel mixture is directed to flow across a flow surface of a first micro-hotplate maintained at a constant temperature. A change in power required to maintain a constant temperature of the first micro-hotplate flow surface due to a convective and conductive heat transfer from the first micro-hotplate flow surface to the air-fuel mixture is measured. The air-fuel mixture is directed to flow across a flow surface of a second micro-hotplate maintained at a constant temperature. The air-fuel mixture is combusted as the air-fuel mixture flows across the second micro-hotplate flow surface. A change in power required to maintain a constant temperature of the second micro-hotplate flow surface due to the combustion of the air-fuel mixture is measured.

Abstract: A microfabricated TID comprises a microhotplate and a thermionic source disposed on the microhotplate. The microfabricated TID can provide high sensitivity and selectivity to nitrogen- and phosphorous-containing compounds and other compounds containing electronegative function groups. The microfabricated TID can be microfabricated with semiconductor-based materials. The microfabricated TID can be combined with a microfabricated separation column and used in microanalytical system for the rapid on-site detection of pesticides, chemical warfare agents, explosives, pharmaceuticals, and other organic compounds that contain nitrogen or phosphorus.

Abstract: A microfabricated field calibration assembly for use in calibrating analytical instruments and sensor systems. The assembly comprises a circuit board comprising one or more resistively heatable microbridge elements, an interface device that enables addressable heating of the microbridge elements, and, in some embodiments, a means for positioning the circuit board within an inlet structure of an analytical instrument or sensor system.

Abstract: A non-planar, tortuous path chemical preconcentrator has a high internal surface area having a heatable sorptive coating that can be used to selectively collect and concentrate one or more chemical species of interest from a fluid stream that can be rapidly released as a concentrated plug into an analytical or microanalytical chain for separation and detection. The non-planar chemical preconcentrator comprises a sorptive support structure having a tortuous flow path. The tortuosity provides repeated twists, turns, and bends to the flow, thereby increasing the interfacial contact between sample fluid stream and the sorptive material. The tortuous path also provides more opportunities for desorption and readsorption of volatile species. Further, the thermal efficiency of the tortuous path chemical preconcentrator is comparable or superior to the prior non-planar chemical preconcentrator.

Abstract: The present invention relates generally to chemical analysis (e.g. by gas chromatography), and in particular to a compact chemical preconcentrator formed on a substrate with a heatable sorptive membrane that can be used to accumulate and concentrate one or more chemical species of interest over time and then rapidly release the concentrated chemical species upon demand for chemical analysis.

Abstract: A microfabricated fuel heating value monitoring device comprises a microfabricated gas chromatography column in combination with a catalytic microcalorimeter. The microcalorimeter can comprise a reference thermal conductivity sensor to provide diagnostics and surety. Using microfabrication techniques, the device can be manufactured in production quantities at a low per-unit cost. The microfabricated fuel heating value monitoring device enables continuous calorimetric determination of the heating value of natural gas with a 1 minute analysis time and 1.5 minute cycle time using air as a carrier gas. This device has applications in remote natural gas mining stations, pipeline switching and metering stations, turbine generators, and other industrial user sites. For gas pipelines, the device can improve gas quality during transfer and blending, and provide accurate financial accounting.

Abstract: A biological preconcentrator comprises a stimulus-responsive active film on a stimulus-producing microfabricated platform. The active film can comprise a thermally switchable polymer film that can be used to selectively absorb and desorb proteins from a protein mixture. The biological microfabricated platform can comprise a thin membrane suspended on a substrate with an integral resistive heater and/or thermoelectric cooler for thermal switching of the active polymer film disposed on the membrane. The active polymer film can comprise hydrogel-like polymers, such as poly(ethylene oxide) or poly(n-isopropylacrylamide), that are tethered to the membrane. The biological preconcentrator can be fabricated with semiconductor materials and technologies.

Abstract: A microfabricated diffusion source to provide for a controlled diffusion rate of a vapor comprises a porous reservoir formed in a substrate that can be filled with a liquid, a headspace cavity for evaporation of the vapor therein, a diffusion channel to provide a controlled diffusion of the vapor, and an outlet to release the vapor into a gas stream. The microfabricated diffusion source can provide a calibration standard for a microanalytical system. The microanalytical system with an integral diffusion source can be fabricated with microelectromechanical systems technologies.

Abstract: A microfabricated mass-sensitive chemical preconcentrator actively measures the mass of a sample on an acoustic microbalance during the collection process. The microbalance comprises a chemically sensitive interface for collecting the sample thereon and an acoustic-based physical transducer that provides an electrical output that is proportional to the mass of the collected sample. The acoustic microbalance preferably comprises a pivot plate resonator. A resistive heating element can be disposed on the chemically sensitive interface to rapidly heat and release the collected sample for further analysis. Therefore, the mass-sensitive chemical preconcentrator can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

Abstract: A non-planar chemical preconcentrator comprises a high-surface area, low mass, three-dimensional, flow-through sorption support structure that can be coated or packed with a sorptive material. The sorptive material can collect and concentrate a chemical analyte from a fluid stream and rapidly release it as a very narrow temporal plug for improved separations in a microanalytical system. The non-planar chemical preconcentrator retains most of the thermal and fabrication benefits of a planar preconcentrator, but has improved ruggedness and uptake, while reducing sorptive coating concerns and extending the range of collectible analytes.