Aspects of the present disclosure are directed to the flow of analytes, particles or other materials. As consistent with one or more embodiments described herein, an apparatus includes a membrane having one or more pores in a membrane. First and second electrodes facilitate electrophoretic flow of analytes through the pore, and a third electrode controls movement of the particles in the pore by modulating the shape of an electric double layer adjacent sidewalls of pore. This modulation controls the strength of an electroosmotic field that opposes the electrophoretic flow of the analytes via the pore.

Devices and methods are provided that permit efficient and selective separation of liquid biological specimens into at least two constituent components to facilitate subsequent quantitative and qualitative analysis on at least one analyte of interest in at least one of the components. The devices generally include one or more sample deposition regions supported on a base. Each sample deposition region includes a separation membrane for separating the liquid biological specimen into two different fractions. The first fraction is trapped by the separation membrane while the second fraction passes through the separation membrane and into a respective collection membrane. The separation and collection membranes are easily separable from the devices and can be utilized for further processing and analysis.

The present invention provides microfluidic devices and methods for using the same. In particular, microfluidic devices of the present invention are useful in conducting a variety of assays and high throughput screening. Microfluidic devices of the present invention include elastomeric components and comprise a main flow channel; a plurality of branch flow channels; a plurality of control channels; and a plurality of valves. Preferably, each of the valves comprises one of the control channels and an elastomeric segment that is deflectable into or retractable from the main or branch flow channel upon which the valve operates in response to an actuation force applied to the control channel.

A microfluidic device for increasing convective clearance of particles from a fluid is provided. A network of first channels can be separated from a network of second channels by a first membrane. The network of first channels can also be separated from a network of third channels by a second membrane. Fluid containing an analyte can be introduced in the network of first channels. Infusate can be introduced into the network of second channels, and waste-collecting fluid can be introduced into the network of third channels. A pressure gradient can be applied in a direction perpendicular to the direction of fluid flow in the network of first channels, such that the analyte is transported from the network of first channels into the network of third channels through the second membrane.

Hydrogen generation assemblies, hydrogen purification devices, and their components, and methods of manufacturing those assemblies, devices, and components are disclosed. In some embodiments, the devices may include an insulation base having insulating material and at least one passage that extends through the insulating material. In some embodiments, the at least one passage may be in fluid communication with a combustion region.

Many hand-held diagnostics are limited in their functionality due to the challenging physics associated with small dimensional systems. An example of this is capillary forces in hydrophilic systems, such as the tight retention of liquid passing through a small pore filtration membrane, or capillary force driven microfluidics where, to keep liquid flowing the dimensions of the system become so small that the flow rates are too low to be useful, or the manufacturing of such devices becomes uneconomical. This disclosure details methods to reset the capillary force condition to avoid the requirement of transient pressure spikes associated with the breakthrough pressure of small pore membranes, and avoid the necessity of extremely small microfluidic channels, which can be useful in applications such as filtration of whole blood to plasma using only suction pressure or passive capillary pressure.

A vacuum manifold for filtration microscopy includes a manifold top having multiple openings, and a capture membrane positioned above and spaced apart from the manifold top, where the capture membrane is configured to deflect into contact with a surface of the manifold top when a negative pressure is applied to the multiple openings. A method for filtration microscopy includes the steps of providing a vacuum manifold including a manifold top having a plurality of openings, and a capture membrane positioned above and spaced apart from the manifold top; applying sample drops to sample spots on the membrane, the sample spots positioned above the plurality of openings; applying a negative pressure to the openings such that the capture membrane contacts a surface of the manifold top; and optically imaging particulates on the capture membrane.

A microfilter comprising a polymer layer formed from photo-definable dry film, and a plurality of apertures each extending through the polymer layer. A microfilter comprising two or more polymer layers formed from photo-definable dry film, and a plurality of apertures or open areas each extending through the polymer layer. Methods of forming apertures in one or more layers of photo-definable dry film are also disclosed. Filter holder designs and methods appropriate to hold microfilters to collect the rare cells and to perform of assays in the filter holder are provided. Microfiltration chip designs and methods appropriate to collect the rare cells and to perform assays in the microfluidic chips are provided. The invention also describes the use of the microfilter, filter holder and microfilter chips to collect rare cells from body fluids and perform assays, and these rare cells can be used for medical and biological research applications.

Provided are nanoporous silicon nitride membranes and methods of making such membranes. The membranes can be part of a monolithic structure or free-standing. The membranes can be made by transfer of the nanoporous structure of a nanoporous silicon or silicon oxide film by, for example, reactive ion etching. The membranes can be used in, for example, filtration applications, hemodialysis applications, hemodialysis devices, laboratory separation devices, multi-well cell culture devices, electronic biosensors, optical biosensors, active pre-concentration filters for microfluidic devices.

Hydrogen generation assemblies, hydrogen purification devices, and their components, and methods of manufacturing those assemblies, devices, and components are disclosed. In some embodiments, the devices may include an insulation base having insulating material and at least one passage that extends through the insulating material. In some embodiments, the at least one passage may be in fluid communication with a combustion region.