Abstract: The present technology describes various embodiments of devices for processing, analyzing, detecting, measuring, and separating fluids. The devices can be used to perform these processes on a microfluidic scale, and with control over fluid and reagent transport. In one embodiment, for example, a device for performing chemical processes can include a porous wick comprising a pathway defined by an input end, an output end, and a length between the input end and the output end. The pathway is configured to wick fluid from the input end to the output end by capillary action. The device can further include a reagent placed on the pathway. The reagent can be placed in a pattern configured to control a spatial or temporal distribution of the reagent along the pathway upon wetting of the pathway.

Abstract: The present technology is directed to capillarity-based devices for performing chemical processes and associated system and methods. In one embodiment, for example, a device can include a base configured to receive one or more fluids, a porous wick carried by the base portion, and a flow-metering element along the porous wick to modify a rate or volume of fluid flow along the porous wick. The porous wick can comprise a first pathway, a second pathway, and an intersection at which the first pathway and the second pathway converge. Input ends of the first and second pathways can be wettably distinct. Upon wetting of the input ends, fluid is configured to travel by capillary action along each pathway. The device may also include volume-metering features configured to automatically and independently control or modify a volume of fluid flow along one or more pathways of the porous wick.

Abstract: Disclosed are methods and devices for rapid parallel molecular affinity assays performed in a microfluidic environment. The invention exploits hydrodynamic addressing to provide simultaneous performance of multiple assays in parallel using a minimal sample volume flowing through a single channel.

Abstract: Devices and methods are provided for separation of particles of a first selected electrophoretic mobility or isoelectric point from a fluid comprising particles of at least one other selected electrophoretic mobility or isoelectric point. The devices comprise a microchannel; electrodes to either side of the microchannel for applying a selected voltage to produce an electrical field across the microchannel orthogonal to the length of the microchannel; and outlets in said microchannel placed to receive outlet portions of the fluid containing enhanced concentrations of each type of particle. The devices may be used for particle detection, quantification, separation, mixing, dilution and concentration; to release, separate and detect interior particles of cells or organisms, and to separate particles such as proteins and microorganisms from biological fluids such as blood; or to separate and detect airborne contaminants such as bacterial warfare agents from air.

Abstract: Disclosed are methods and devices for rapid parallel molecular affinity assays performed in a microfluidic environment. The invention exploits hydrodynamic addressing to provide simultaneous performance of multiple assays in parallel using a minimal sample volume flowing through a single channel.

Abstract: Disclosed is a flow-through membrane assay that takes advantage of a high surface area and rapid transport while allowing individual control over flow rates and times for each step of a multi-step assay. A microfluidic card features channels in communication with a porous membrane, channels on either side of membrane to allow transverse flow across the membrane, capturing a labeled target from the sample by flowing the sample across the membrane, or capturing a target from the sample followed by flowing a reagent containing a label that binds to the target. Fluid can be pushed or pulled through the assay membrane by external control. Air near the membrane is managed by diverting air between fluids to a channel upstream of the assay membrane, venting air between fluids through a hydrophobic membrane upstream of the assay membrane, and/or by venting trapped air through a hydrophobic membrane downstream of the assay membrane.

Abstract: Disclosed is a microfluidic assay system and methods that apply flow injection analysis to permit dispersion monitoring. A solution containing a reagent that binds an analyte and a tracer is delivered via pressure-driven flow into the receiving end of the injection channel of the system of the invention. A sample fluid suspected of containing the analyte is delivered into the upstream end of the input channel under conditions permitting flow of the sample fluid toward the downstream end of the assay channel and permitting dispersion of the reagent into the sample fluid. The amount of tracer present in the fluid as it passes over the reference region and the capture region and the amount of binding between the analyte and the capture region are detected. The amount of binding detected between the analyte and the capture region is correlated to the amount of tracer detected in the reference region.

Abstract: Disclosed are methods and devices for rapid parallel molecular affinity assays performed in a microfluidic environment. The invention exploits hydrodynamic addressing to provide simultaneous performance of multiple assays in parallel using a minimal sample volume flowing through a single channel.

Abstract: The invention provides a method, apparatus and system for detecting electrochemical oxidoreduction activity mediated by a redox enzyme at a site remote from the enzyme. In one embodiment, the method comprises immobilizing the redox enzyme on a first region of a conductive surface and contacting a substrate capable of producing a detectable signal upon oxidation or reduction with a second region of the conductive surface. The second region is electrically coupled with the first region and the redox enzyme is not present in the second region. The method further comprises exposing the immobilized redox enzyme to conditions that effect oxidation or reduction of the enzyme, and detecting oxidation or reduction of the substrate at the second region. The invention can be adapted for detecting a plurality of analytes.

Abstract: An approach is described for identifying sites of imminent skin breakdown in amputee prosthesis users. Thermal recovery time (TRT) for a limb is optically determined using an infrared camera. TRT is the time interval for the temperature of the skin to achieve 70% of its maximum value during a 10-minute recovery period after a subject has completed a standing/walk-in-place procedure. A limb tolerance map is produced in which 5×5 pixel squares are colored to indicate their TRT and labeled to indicate a temperature vs. time curve (indicative of blood flow characteristics) for the square. TRT data can also be used for prosthetic fitting and socket replacement, by locating tolerant/intolerant regions on a limb and providing a visual “limb tolerance map” for a proposed socket design and applied to other areas, such as the design of shoes for patients with insensate feet, cushions for wheelchair users, and mattresses for bedridden patients.

Abstract: An improved microscale diffusion immunoassay utilizing multivalent reactants is disclosed. In particular, a method for detecting the presence of analyte particles in an analyte fluid is disclosed, the method comprising: (a) providing the analyte fluid comprising the analyte particles; (b) providing a diffusion fluid comprising binding particles capable of binding with the analyte particles; (c) flowing the analyte fluid and the diffusion fluid in adjacent laminar flow through a microfluidic channel; (d) allowing the analyte particles to diffuse into the diffusion fluid and bind with the binding particles to form analyte/binding particle complexes; and (e) detecting the presence of the analyte particles and the analyte/binding particle complexes, wherein each of the binding particles is capable of binding with more than one analyte particle, and wherein each of the analyte particles is capable of binding with more than one binding particle.

Abstract: Disclosed is a microfluidic assay system and methods that apply flow injection analysis to permit dispersion monitoring. A solution containing a reagent that binds an analyte and a tracer is delivered via pressure-driven flow into the receiving end of the injection channel of the system of the invention. A sample fluid suspected of containing the analyte is delivered into the upstream end of the input channel under conditions permitting flow of the sample fluid toward the downstream end of the assay channel and permitting dispersion of the reagent into the sample fluid. The amount of tracer present in the fluid as it passes over the reference region and the capture region and the amount of binding between the analyte and the capture region are detected. The amount of binding detected between the analyte and the capture region is correlated to the amount of tracer detected in the reference region.

Abstract: The present invention provides methods and compositions for amplifying the detection signal in surface plasmon resonance (SPR)-based flow systems. The signal amplification methods comprise the use of well established marker systems that provide a precipitate. The marker systems include, for example, enzyme and nucleation systems. Enzymes suitable for use as a marker system include peroxidases and phosphatases. The amplification system is useful in any SPR-based detection system including microfluidic systems, e.g., “lab on a chip” systems and the like. The methods can comprise any SPR-based assay format, including typical immunoassay formats. The immunoassay formats can include competitive and sandwich assays. Analyte capture agents can include antibodies, lectins, carbohydrates, polynucleotides, receptor proteins, and the like.

Abstract: The invention provides a method, apparatus and system for detecting electrochemical oxidoreduction activity mediated by a redox enzyme at a site remote from the enzyme. In one embodiment, the method comprises immobilizing the redox enzyme on a first region of a conductive surface and contacting a substrate capable of producing a detectable signal upon oxidation or reduction with a second region of the conductive surface. The second region is electrically coupled with the first region and the redox enzyme is not present in the second region. The method further comprises exposing the immobilized redox enzyme to conditions that effect oxidation or reduction of the enzyme, and detecting oxidation or reduction of the substrate at the second region. The invention can be adapted for detecting a plurality of analytes.

Abstract: The invention provides a method, apparatus and system for detecting electrochemical oxidoreduction activity mediated by a redox enzyme at a site remote from the enzyme. In one embodiment, the method comprises immobilizing the redox enzyme on a first region of a conductive surface and contacting a substrate capable of producing a detectable signal upon oxidation or reduction with a second region of the conductive surface. The second region is electrically coupled with the first region and the redox enzyme is not present in the second region. The method further comprises exposing the immobilized redox enzyme to conditions that effect oxidation or reduction of the enzyme, and detecting oxidation or reduction of the substrate at the second region. The invention can be adapted for detecting a plurality of analytes.

Abstract: A seal (10) for sealing the interface between a shaft (12) and a bore-defining wall (14) of a surrounding part (16). The seal (10) comprises a sleeve (20) for movement (or nonmovement) with the shaft (12), a case (30) for movement (or nonmovement) with the surrounding part (16), a bumper lip (40), a dirt lip (42), and a primary lip (44). A drain passage (60) continuously empties a potentially contaminant-accumulating chamber (50) between the bumper lip (40) and the dirt lip (42) thereby circumventing any contaminant ingress towards the primary lip (44).

Abstract: Methods and apparatuses are provided for determining presence and concentration of analytes by exploiting molecular binding reactions and differential diffusion rates. Analyte particles and binding particles are allowed to diffuse toward each other, and slowing of the diffusion front is detected when they meet. From the position of the diffusion front, presence and concentration of analyte particles can be determined. One embodiment provides a competitive immunoassay in a microfluidic format. This diffusion immunoassay (DIA) relies on measuring the concentration of labeled antigen along one dimension of a microchannel after allowing it to diffuse for a short time into a region containing specific antibodies. A simple microfluidic device, the T-Sensor, was used to implement a DIA to measure the concentration of phenytoin, a small drug molecule. Concentrations of analyte over the range of 50 to 1600 nM can be measured in less than a minute.

Abstract: The invention provides a method, apparatus and system for detecting electrochemical oxidoreduction activity mediated by a redox enzyme at a site remote from the enzyme. In one embodiment, the method comprises immobilizing the redox enzyme on a first region of a conductive surface and contacting a substrate capable of producing a detectable signal upon oxidation or reduction with a second region of the conductive surface. The second region is electrically coupled with the first region and the redox enzyme is not present in the second region. The method further comprises exposing the immobilized redox enzyme to conditions that effect oxidation or reduction of the enzyme, and detecting oxidation or reduction of the substrate at the second region. The invention can be adapted for detecting a plurality of analytes.

Abstract: This invention provides a microfluidic device for use in the detection of one or more analytes in a fluid using solid-phase affinity binding assays. The device offers a practical, easy-to-use, portable, inexpensive, robust analytical system for the parallel and quantitative detection of multiple analytes. In addition, this invention provides methods and devices for the formation of concentration gradients of capture molecules immobilized on a solid phase.

Abstract: A method for fabricating an adhesiveless microfluidic device using solvent assisted thermal welding is provided. The method comprises use of a plurality of device layers of a bulk chemical conformation composition having a glass transition temperature that can be disrupted by a disrupting agent without total solvation, wherein the plurality of device layers when assembled define a plurality of defined component features. The device layers are immersed into the disrupting agent for a time period sufficient to disrupt the glass transition temperature of a defined depth of the surfaces of the device layers prior to their removal from the disrupting agent. The plurality of device layers are assembled and registered by contacting the plurality of device layer surfaces to form the defined component features.