Abstract: The present invention relates to microfluidic systems, including valves and pumps for microfluidic systems. The valves of the invention include check valves such as diaphragm valves and flap valves. Other valves of the invention include one-use valves. The pumps of the present invention include a reservoir and at least two check valves. The reservoir may be of variable volume. The present invention also relates to a flexible microfluidic system. The present invention additionally relates to a method of making microfluidic systems including those of the present invention. The method includes forming a microfluidic system on a master, connecting a support to the microfluidic system and removing the microfluidic system from the master. The support may remain connected to the microfluidic system or the microfluidic system may be transferred to another substrate. The present invention further relates to a method of manipulating a flow of a fluid in a microfluidic system.

Abstract: Paper-based microfluidic systems and methods of making the same are described.

Abstract: Three-dimensional cellular arrays, methods of making three-dimensional cellular arrays, and methods of identifying agents using the arrays are disclosed.

Abstract: A system is provided for positioning separate portions of a sample in elongate, parallel channels of a sample chamber and for irradiating a sample in the chamber to create a diffraction pattern where the sample and chamber differ in refractive index. The system also can measure absorption of electromagnetic radiation by a sample in the chamber, and can measure the absorption simultaneously with measurement of diffraction by the sample.

Abstract: Disclosed herein are a variety of microfluidic devices and solid, typically electrically conductive devices that can be formed using such devices as molds. In certain embodiments, the devices that are formed comprise conductive pathways formed by solidifying a liquid metal present in one or more microfluidic channels (such devices hereinafter referred to as “microsolidic” devices). In certain such devices, in which electrical connections can be formed and/or reformed between regions in a microfluidic structure; in some cases, the devices/circuits formed may be flexible and/or involve flexible electrical components. In certain embodiments, the solid metal wires/conductive pathways formed in microfluidic channel(s) may remain contained within the microfluidic structure. In certain such embodiments, the conductive pathways formed may be located in proximity to other microfluidic channel(s) of the structure that carry flowing fluid, such that the conductive pathway can create energy (e.g.

Abstract: The present invention is directed to adhesive systems and methods of making and using such systems. Exemplary adhesive systems comprise protrusions and/or grooves that can interleave to form a reversible adhesive interaction.

Abstract: Improved methods of forming a patterned self-assembled monolayer on a surface and derivative articles are provided. According to one method, an elastomeric stamp is deformed during and/or prior to using the stamp to print a self-assembled molecular monolayer on a surface. According to another method, during monolayer printing the surface is contacted with a liquid that is immiscible with the molecular monolayer-forming species to effect controlled reactive spreading of the monolayer on the surface. Methods of printing self-assembled molecular monolayers on nonplanar surfaces and derivative articles are provided, as are methods of etching surfaces patterned with self-assembled monolayers, including methods of etching silicon. Optical elements including flexible diffraction gratings, mirrors, and lenses are provided, as are methods for forming optical devices and other articles using lithographic molding.

Abstract: The present invention generally relates to lasers comprising fluidic channels, such as microfluidic channels. In some instances, the channel contains two or more fluids. The fluids may remain non-mixed within the channel, for example, due to immiscibility and/or laminar flow within the channel. The fluids may be arranged in the channel such that light propagating in a first fluid is prevented by the second fluid from exiting the first fluid, for example, due to differences in the indexes of refraction (e.g., causing internal reflection of the fluid to occur). Thus, in one embodiment, a first fluid may be at least partially surrounded by a second fluid having a second index of refraction lower than the index of refraction of the first fluid. In some embodiments, the fluidic channel is used as a laser, for instance, a dye laser, i.e., a laser created by directing light at a dye to produce coherent light. The dye may be present in one or more fluids within the fluidic channel.

Abstract: The ability to levitate, to separate, and to detect changes in density using diamagnetic particles suspended in solutions containing paramagnetic cations using an inhomogeneous magnetic field is described. The major advantages of this separation device are that: i) it is a simple apparatus that does not require electric power (a set of permanent magnets and gravity are sufficient for the diamagnetic separation and collection system to work); ii) it is compatible with simple optical detection (provided that transparent materials are used to fabricate the containers/channels where separation occurs; iii) it is simple to collect the separated particles for further processing; iv) it does not require magnetic labeling of the particles/materials; and v) it is small, portable.

Abstract: An assay method is described, which comprises the steps of immobilizing a binding partner (e.g., an antigen or antibody) for an analyte to be detected (e.g., an antibody or antigen) on a portion of a surface of a microfluidic chamber; passing a fluid sample over the surface and allowing the analyte to bind to the binding partner; allowing a metal colloid, e.g., a gold-conjugated antibody, to associate with the bound analyte; flowing a metal solution, e.g., a silver solution, over the surface such as to form an opaque metallic layer; and detecting the presence of said metallic layer, e.g., by visual inspection or by measuring light transmission through the layer, conductivity or resistance of the layer, or metal concentration in the metal solution after flowing the metal solution over the surface.

Abstract: In one aspect, methods of patterning of thin films of an ionotropic polymer (e.g., poly(acrylic acid)) are provided. These processes can create micron or sub-micron-scale patterns of ionotropic polymers such as cation crosslinked poly(acrylic acid) (CCL-PAA). In one embodiment, patterning may be performed within microfluidic channels by flowing a solution of crosslinking agent (e.g., metal cations such as Ag+, Ca2+, Pd2+, Al3+, La3+, and Ti4+) that can crosslink a portion of an ionotropic polymer in contact with the solution. In another embodiment, methods of patterning ionotropic polymers involve photolithography. Upon patterning a positive photoresist (e.g., diazonaphthoquinone-novolac resin) on a film of CCL-PAA, the exposed regions of CCL-PAA can be etched by an aqueous solution. Advantageously, the patterned, crosslinked polymer may also serve as both a reactant and a matrix for subsequent chemistry.

Abstract: A method of forming microstructures. An article including a metal atom precursor is disproportionally exposed to electromagnetic radiation in an amount and intensity sufficient to convert some of the precursor to elemental metal. Additional conductive material may then be deposited onto the elemental metal to produce a microstructure.

Abstract: A method and apparatus for providing electric microcontact printing is provided. A stamp is brought into contact with the surface of a substrate to provide high resolution features. Aspects of the invention may be used for data storage, microcontact printing, and for other applications requiring high resolution pattern transfer.

Abstract: A microfluidic method and device for focusing and/or forming discontinuous sections of similar or dissimilar size in a fluid is provided. The device can be fabricated simply from readily-available, inexpensive material using simple techniques.

Abstract: The present invention is directed to substrates comprising amplified patterns, methods for making the amplified patterns, and methods of using the amplified patterns to form surface features on the substrates.

Abstract: The present invention relates to fluidic systems and, in particular, fluidic arrays and methods for using them to promote interaction of materials. In one embodiment, the present invention is directed to a microfluidic system. The microfluidic system includes a first fluid path and a second fluid path segregated from the first fluid path by a first convection controller at a first contact region, wherein at least one of the first fluid path and the second fluid path has a cross-sectional dimension of less than about 1 millimeter. In another aspect, the present invention is directed to a method of promoting interaction. In another aspect, the invention relates to a device and method for performing titrations.

Abstract: A series of methods, compositions, and articles for patterning a surface with multiple, aligned layers of molecules, by exposing the molecules to electromagnetic radiation is provided. In certain embodiments, a single photomask acts as an area-selective filter for light at multiple wavelengths. A single set of exposures of multiple wavelengths through this photomask may make it possible to fabricate a pattern comprising discontinuous multiple regions, where the regions differ from each other in at least one chemical and/or physical property, without acts of alignment between the exposures. In certain embodiments, the surface includes molecules attached thereto that can be photocleaved upon exposure to a certain wavelength of radiation, thereby altering the chemical composition on at least a portion of the surface.

Abstract: An assay method is described, which comprises the steps of immobilizing a binding partner (e.g., an antigen or antibody) for an analyte to be detected (e.g., an antibody or antigen) on a portion (140) of a surface (130) of a microfluidic chamber (120,122,124); passing a fluid sample over the surface and allowing the analyte to bind to the binding partner; allowing a metal colloid, e.g., a gold-conjugated antibody, to associate with the bound analyte; flowing a metal solution, e.g., a silver solution, over the surface such as to form an opaque metallic layer; and detecting the presence of said metallic layer, e.g., by visual inspection or by measuring light transmission through the layer, conductivity or resistance of the layer, or metal concentration in the metal solution after flowing the metal solution over the surface.

Abstract: Techniques for self assembly of macro-scale objects, optionally defining electrical circuitry, are described, as well as articles formed by self assembly. Components can be joined, during self-assembly by minimization of free energy, capillary attraction, or a combination.

Abstract: A microfluidic valve assembly includes a structure defining a microfluidic fluid path and an actuator that can be moved between different positions controlling flow through the channel. In one embodiment, the actuator can be threaded into at least a portion of the structure, and can be moved rotationally between a first position, causing relatively greater constriction of a microfluidic fluid path, and a second position causing relatively lesser constriction of the fluid path. Actuating the actuator, e.g., by rotation, can deform material between the valve and the fluid path, thereby constricting at least a portion of the underlying fluid path and regulating the flow of a fluid in the fluid path. In another aspect, the invention provides a reservoir into which fluid can be placed and from which fluid can be introduced into a microfluidic system. In one embodiment, the reservoir is expandable and thereby able to store fluid under pressure for delivery to a microfluidic system.