Provided are monolithic structures comprising one or more suspended, nanoporous membranes that are in contact with one or more fluidic cavities, methods of making same, and exemplary uses of same. The monolithic structures can be formed using a transmembrane etch. The monolithic structures can be used, as examples, as filters and filtration modules in microfluidic devices, dialysis devices, and concentration devices in laboratory, industrial, and medical processes.

The present disclosure provides a method for producing a water permeable molecular sieve in which a porous substrate having micron-size pores has deposited on a surface thereof non-porous 2D platelets to seal, at the substrate surface, pores in the porous substrate to form a layer of 2D platelets. A curable sealing material is deposited onto the layer of 2D platelets and any remaining exposed areas of the surface of the porous substrate and curing the curable sealing material in order to form a sealed layer on the surface of the porous substrate to prevent water by-passing the non-porous 2D platelets and passing through the porous substrate. An array of sub-nanopores are then produced through the sealed layer with the array of sub-nanopores having a size to allow water to pass therethrough but not metal ions to give a water permeable molecular sieve characterized by water permeability at low di?erential pressures.

A method comprises forming etching islands on a substrate and exposing the substrate with etching islands to a solution that reacts with the etching islands to form a filter passage of interconnected pores in the substrate. The filter passage has an inlet into the substrate and an outlet from the substrate.

Microdialysis sampling is an essential tool for in vivo neuro-chemical monitoring. Conventional dialysis probes are over 220 ?m in diameter and have limited flexibility in design because they are made by assembly using preformed membranes. The probe size constrains spatial resolution and governs the amount of tissue damaged caused by probe insertion. To overcome these limitations, we have developed a method to microfabricate probes in Si that are 45 ?m thick 180 ?m wide. The probes contain a buried, U-shaped channel that is 30 ?m deep 60 ?m wide and terminates in ports for external connection. A 4 mm length of the probe is covered with a 5 ?m thick nanoporous membrane. The membrane was microfabricated by deep reactive ion etching through a porous aluminum oxide layer. The microfabricated probe has cross-sectional area that is 79% less than that of the smallest conventional microdialysis probes. The probes yield 2-7% relative recovery at 100 nL/min perfusion rate for a variety of small molecules. The probe was successfully tested in vivo by sampling from the striatum of live rats. Fractions were collected at 20 min intervals (2 ?L) before and after an injection of 5 mg/kg, i.p amphetamine. Analysis of fractions by liquid chromatography-mass spectrometry revealed reliable detection of 13 neurochemicals, including dopamine and acetylcholine, at basal conditions. Amphetamine evoked a 43-fold rise in dopamine, a result nearly identical to a conventional dialysis probe in the same animal. The microfabricated probes have potential for sampling with higher spatial resolution and less tissue disruption than conventional probes. It may also be possible to add functionality to the probes by integrating other components, such as electrodes, optics, and additional channels.

Methods and apparatus for forming apertures in a solid state membrane using dielectric breakdown are provided. In one disclosed arrangement a plurality of apertures are formed. The membrane comprises a first surface area portion on one side of the membrane and a second surface area portion on the other side of the membrane. Each of a plurality of target regions comprises a recess or a fluidic passage opening out into the first or second surface area portion. The method comprises contacting all of the first surface area portion of the membrane with a first bath comprising ionic solution and all of the second surface area portion with a second bath comprising ionic solution. A voltage is applied across the membrane via first and second electrodes in respective contact with the first and second baths comprising ionic solutions to form an aperture at each of a plurality of the target regions in the membrane.

A structure that includes a substrate and a nanofilter formed on the substrate, wherein the nanofilter is adapted to allow nanoparticles of a predetermined size to pass through the nanofilter.

Embodiments in accordance with the present invention relate to the use of effusive filtration to segregate tumor cells from a sample of bodily fluid. In one embodiment, fluid containing a cell is flowed down a channel having a filtration medium present along at least one side wall. The tumor cell is captured when the fluid passes through the filtration medium. Accumulated pressure on the captured tumor cell is reduced by allowing the fluid that has passed through the filtration medium to re-enter the channel. In a particular embodiment, the filtration medium may comprise side wall apertures having a width smaller than that of the cell, with downstream apertures allowing re-entry of the fluid into the channel.

Methods for making multiple walled nested coaxial nanostructures and devices incorporating the coaxial nanostructures are disclosed. The coaxial nanostructures include an inner nanostructure, a first outer nanotube disposed around the inner nanostructure, and a first annular channel between the inner nanostructure and the first outer nanotube. The coaxial nanostructures have extremely high aspect ratios, ranging from about 5 to about 1,200, or about 300 to about 1200.

A filter membrane for selectively separating a specific material from other materials in a processing medium includes a membrane including resin material and having openings formed such that the openings selectively separate a specific material from other materials in a processing medium. The membrane has a first surface and a second surface on the opposite side with respect to the first surface such that the first surface receives the processing medium supplied to the membrane, the openings are formed through the membrane such that each of the openings has an opening part extending from the second surface toward the first surface and an expansion part expanding a size of the opening part and extending from the opening part to the first surface, and the first surface of the membrane is divided into multiple regions.

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.