Abstract: Compositions and methods are provided for performing capillary electrophoresis using a composition comprising in combination in an aqueous buffered medium a coating polymer and a sieving polymer, where the sieving polymer is more hydrophilic than the coating polymer and is present in greater amount. Of particular interest are uncrosslinked acrylamide polymer mixtures for coating plastic channels and providing sieving for performing DNA separations in microfluidic devices. Polyacrylamide or N,N-dimethyl acrylamide is used with a N,N-dialkyl acrylamide copolymer, either separately or together for sieving and coating, serving as the medium in capillary electrophoresis DNA separations.

Abstract: Capillary electrophoresis is performed under conventional conditions in microchannels having a norbornene based polymer surface. The norbornene based polymers can be used as a solid substrate for forming the necessary features for a microfluidic device, where the entire device may be made of norbornene based polymer. Conveniently, a norbornene based polymer layer having a lower glass transition temperature may be used to adhere a cover or enclosing layer to the substrate to enclose the microchannels and provide a bottom for the reservoirs.

Abstract: Methods of sample loading and separation in a microfluidics device are described. The methods provide high resolution and high signal intensity, using, in a preferred embodiment, a simple two-electrode injection scheme with transient isotachophoretic (ITP) stacking.

Abstract: Probe sets for the multiplexed detection of the binding of, or interaction between, one or more ligands and target antiligands are provided. Detection involves the release of identifying tags as a consequence of target recognition. The probe sets include electrophoretic tag probes or e-tag probes, comprising a detection region and a mobility-defining region called the mobility modifier, both linked to a target-binding moiety. The probes comprise interactive functionalities adjacent the cleaved portion positioned in the probes such that the interactive functionality does not form part of the e-tag reporters. Target antiligands are contacted with a set of e-tag probes and the contacted antiligands are treated with a selected cleaving agent resulting in a mixture of e-tag reporters and uncleaved and/or partially cleaved e-tag probes. The mixture is exposed to a capture agent effective to bind to uncleaved or partially cleaved e-tag probes, followed by electrophoretic separation.

Abstract: An improved microfluidics device and system for sample loading and injection are disclosed. The device includes three main channels—a separation channel, supply channel, and drain channel—for use in loading and injecting a sample from the supply channel. Pairs of peripheral channels connecting the supply channel with upstream and downstream regions of the separation channel, and connecting supply and drain channels to a downstream region of the separation channel promote fluid flow and/or ion in the channel network to effect (i) sample shaping in the separation channel, when an electrokinetic or pneumatic force is applied between the supply and drain channels, and (ii) sample pullback in the supply and drain channels, when an electrokinetic or pneumatic force is applied between opposite ends of the separation channel. The system incorporates the device, electrodes that interact with reservoirs in the device, and a control unit.

Abstract: A method of separating components having a given negative or positive charge and contained in a sample is disclosed. The method involves, in one embodiment, loading a microchannel with a sample, placed between a trailing-edge electrolyte having a selected concentration of a titratable species, and a leading-edge electrolyte.

Abstract: A method of separating components having a given negative or positive charge and contained in a sample is disclosed. The method involves, in one embodiment, loading a microchannel with a sample, placed between a trailing-edge electrolyte having a selected concentration of a titratable species, and a leading-edge electrolyte.

Abstract: Methods for the multiplexed detection of known, selected nucleotide target sequences are provided. Detection involves the release of identifying tags as a consequence of target recognition. The methods include the use of electrophoretic tag probes or e-tag probes, comprising a detection region and a mobility-defining region called the mobility modifier, both linked to a target-binding moiety. In practicing the methods, the target-binding moiety of the e-tag probes hybridizes to complementary target sequences followed by nuclease cleavage of the e-tag probes and release of detectable e-tags or e-tag reporters. The mixture is exposed to a capture agent which binds uncleaved and/or partially cleaved e-tag probes, followed by electrophoretic separation. In a multiplexed assay, different released e-tag reporters may be separated and detected providing for target identification.

Abstract: Methods and compositions are provided for detecting DNA sequences, particularly single nucleotide polymorphisms, using a pair of nucleotide sequences, a primer and a snp detection sequence, where the snp detection sequence binds downstream from the primer to the target DNA in the direction of primer extension. The snp detection sequence is characterized by having a nucleotide complementary to the snp and adjacent nucleotides complementary to adjacent nucleotides in the target and an electrophoretic tag bonded to the 5′-nucleotide. The pair of sequences is combined with the target DNA under primer extension conditions, where the polymerase has 5′-3′ exonuclease activity. When the snp is present, the electrophoretic tag is released and can be detected by electrophoresis as indicative of the presence of the snp in the target DNA. The sequence containing the snp is exemplary of DNA sequences of interest generally.

Abstract: Electrophoretic probes comprising fluorescent compounds as detection groups and mobility modifiers are disclosed for the multiplexed detection of the binding of, or interaction between, one or more ligands and target antiligands are provided. In one embodiment, detection involves the release of identifying tags as a consequence of target recognition. Target antiligands are contacted with a set of e-tag probes and the contacted antiligands are treated with a selected cleaving agent resulting in a mixture of e-tag reporters. Typically, uncleaved or partially cleaved e-tag probes are removed and the mixture of e-tag reporters is separated by any technique that provides for separation by mass or mass to charge ratio and the like and detected to provide for target identification.

Abstract: The invention provides a method for detecting a target analyte, by: (a) contacting one or more target analytes with a set of first and second binding reagents under conditions sufficient for binding of a target analyte with the first and second binding reagents, each of the first binding reagents containing a cleavage-inducing moiety and a target binding moiety, each of the second binding reagents containing a tagged probe having a mass modifier region attached to a target binding moiety by a cleavable linkage, the cleavable linkage being susceptible to cleavage when in proximity to an activated cleavage-inducing moiety; (b) activating the cleavage-inducing moiety to release a tag reporter, and (c) detecting a mass of the tag reporter, the mass uniquely corresponding to a known target analyte.

Abstract: Cytochrome P-450 assay methods and kits for the methods are provided employing a cytochrome P-450 enzyme, substrates characterized by having an oxidizable methylene group oxidized to an aldehyde and a fluorescent hydrazine. A fluorescent hydrazine is added to the reaction mixture and the resulting hydrazone analyzed by capillary electrophoresis. The method finds use in evaluating compounds for enzyme modulating activity.

Abstract: Methods and compositions are provided for determining large numbers of single nucleotide polymorphisms in target DNA employing particles having (1) primers complementary to sequences in the target DNA where the next succeeding 3′-nucleotide is a potential single nucleotide polymorphism and coding composition members, where the members are unique for each primer, and (2) differentially labeled terminating nucleotides, where the label permits separation of the terminating nucleotides. Desirably the particles are separated into groups having a common prevalent next succeeding nucleotide. The particles and target DNA are combined under nucleotide extending conditions, the particles separated into groups in accordance with the terminating nucleotide and the coding members identified, so that one knows the sequence and the single nucleotide polymorphism. Various protocols are provided for the determination.

Abstract: A multiplexed enzyme assay method and substrate set for performing the method are disclosed. The method includes performing a plurality of enzyme reactions in the presence of a plurality of enzymes substrates, under conditions effective to convert an enzyme substrate to a corresponding product, where the product of each substrate and the substrate have different separation characteristics from each other and from the other substrates and their corresponding products. After performing the reactions, which may be carried out in separate or combined reactions, the substrates and products in said reactions are separated in a single separation medium. For each separated product and substrate, a separation characteristic effective to identify that product and substrate and a signal related to the amount of the product and substrate is detected. From this, one can determine the amount of substrate converted to the corresponding product in each of the reactions.

Abstract: Families of compositions are provided as labels, referred to as eTag reporters for attaching to polymeric compounds and assaying based on release of the eTag reporters from the polymeric compound and separation and detection. For oligonucleotides, the eTag reporters are synthesized at the end of the oligonucleotide by using phosphite or phosphate chemistry, whereby mass-modifying regions, charge-modifying regions and detectable regions are added sequentially to produce the eTag labeled reporters. By using small building blocks and varying their combination large numbers of different eTag reporters can be readily produced attached to a binding compound specific for the target compound of interest for identification. Protocols are used that release the eTag reporter when the target compound is present in the sample.

Abstract: Devices and methods are provided using microfluidic devices for manipulating small volumes and determining a variety of chemical and physical events. The devices rely upon an opening to the atmosphere of a small volume in a zone, where a sample is placed in the zone where evaporation can occur. The zone is maintained in contact with a liquid medium that serves to replenish the liquid in the zone and maintain the composition of the mixture in the zone substantially constant. The diffusion of components in the zone is restricted during the course of the determination by the liquid flux into the zone.

Abstract: Multilevel microfluidic structures and their use are provided for performing operations using electrokinetic or pneumatic force for moving sample components through and between levels. The devices have flow systems comprising microstructures including reservoirs, channels and vias, where each of the levels or lamina has a plurality of microstructures, and where the microstructures may communicate between levels.

Abstract: An optical detection and orientation device is provided comprising housing having an excitation light source, an optical element for reflecting the excitation light to an aspherical lens and transmitting light emitted by a fluorophore excited by said excitation light, a focussing lens for focusing the emitted light onto the entry of an optical fiber, which serves as a confocal aperture, and means for accurately moving said housing over a small area in relation to a channel in a microfluidic device. The optical detection and orientation device finds use in identifying the center of the channel and detecting fluorophores in the channel during operations involving fluorescent signals.

Abstract: Cell based assays are performed in a microfluidic device, where the cells are introduced into a reservoir and are contacted with one or more agents prior to or during their residence in the reservoir or in a capillary channel connected to the reservoir. The cells are moved by electrokinesis individually from the reservoir to a detector, where the status of the cells as a result of contacting said agents is determined. Conditions are provided for moving the cells electrophoretically or by electroosmotic force, where the cells may be viable or fixed, natural or genetically modified.

Abstract: Integrated microfluidic devices comprising at least an enrichment channel (10) and a main electrophoretic flowpath (12) are provided. In the subject integrated devices, the enrichment channel and the main electrophoretic flowpath are positioned so that waste fluid flows away from said main electrophoretic flowpath through a discharge outlet (6). The subject devices find use in a variety of electrophoretic applications, including clinical assays, high throughput screening for genomics and pharmaceutical applications, point-or-care in vitro diagnostics, molecular genetic analysis and nucleic acid diagnostics, cell separations, and bioresearch generally.