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: Methods, devices, and systems for unbiased transport of materials on a microfluidic device are disclosed, including methods of maintaining the starting composition of an analyte during transport, and methods of simultaneously analyzing both cationic and anionic components of an analyte. Analyte is loaded into a four-way junction of channels by controlled differential pressure applied to the channels. After analyte loading, an electrical potential is established, forcing charged species into at least one of two separation channels.

Abstract: The present invention concerns an apparatus for conducting a microfluidic process. The apparatus comprises integral first and second plates. The first plate comprises an array of sample receiving elements for receiving a plurality of samples from an array of sample containers and dispensing the samples. The second plate comprises a planar array of microfluidic networks of cavity structures and channels for conducting a microfluidic process. Also disclosed is a method for processing an array of samples. At least a portion of each sample in an array of sample wells is simultaneously transferred to a corresponding array of microfluidic networks of cavity structures and channels by means of a corresponding array of sample receiving elements that is in integral fluid communication with the array of microfluidic networks. The samples are then processed.

Abstract: Electrophoretic chambers having at least a region of surface modification, and methods for their fabrication, are provided. In some embodiments the subject chambers include in the region of surface modification an anchoring polymeric layer interpenetrating the surface of the chamber and an electrophoretic polymeric layer copolymerized with the anchoring polymeric layer. The subject chambers are prepared by sequentially contacting the chamber surface with a first monomer capable of interpenetrating the surface and a second monomer capable of copolymerization with the first monomer, followed by copolymerization of the first and second monomers. In other embodiments an electrophoretic polymeric layer is noncovalently bound on the surface of a rigid polymereic base material without the aid of a separate anchoring polymeric layer. The subject devices find use in any of a variety of electrophoretic applications in which entities are moved through a medium under the influence of an applied electric field.

Abstract: The present invention describes a method of sequencing nucleic acids in which mixtures of oligonucleotide fragments are derived from sequencing reactions using combinations of the 2',3'-dideoxynucleoside 5'-triphosphate or 3' deoxynucleoside 5'-triphosphate terminators and appropriate concentrations of four dNTPs (2'-deoxynucleoside 5' triphosphates, e.g., dATP, dCTP, dGTP, dTTP, dITP, 7-deaza-GTP). These fragments are generated by enzymatic extension of a primer hybridized to the single-stranded template DNA to be sequenced. In contrast to common slab gel sequencing methods, the method of the instant invention does not require precise alignment of the four separation sets of the terminated fragments to permit deduction of the DNA sequence. In addition, the method possesses inherent redundancy in the separations, which facilitates sequence assignment by resolving sequence uncertainties or anomalies.

Abstract: A method and device are provided for transporting a liquid sample into a third microchannel from an intersection of at least a first, a second, and a fourth microchannel, by stages. In a first stage, liquid sample is moved in and from the fourth microchannel through the intersection and into the second microchannel and concurrently carrier liquid is moved in and from the first and third microchannels through the intersection and into the second microchannel. Thereafter in a second stage, at least part of the contents of the intersection is moved into the third channel and concurrently a part of the contents of the second and fourth microchannels is moved through the intersection and into the third microchannel. Thereafter in a third stage, carrier liquid is moved from the first microchannel simultaneously through the intersection and into the second, third, and fourth microchannels.

Abstract: A method for extending the useful lifetime and improving the reproducibility of electrophoresis gels, particularly gel-filled capillaries. The polarity of the applied electric field imposed across the gel is periodically reversed between one or more electrophoretic runs.

Abstract: The present invention sorts microorganism populations from a mixture which contains more than one microorganism population. Microorganisms of different types vary in size, shape, and surface charge characteristics. These characteristics we believe contribute to the rate of migration for microorganisms under the influence of an electric field. Microorganisms of the same population (genus and species) will migrate similarly. By applying an electric field in a direction opposite the direction of fluid flow, separation is enhanced.

Abstract: This invention involves method and apparatus for multiplexing electrophoresis analysis. An array of samples in multi well plates are simultaneously transferred to an array of electrophoresis column where electrophoresis is simultaneously carried out followed by analysis of the columns. The methods and apparatus of this invention are, for example, useful for DNA analysis, including sequencing, and for measuring reactions between specifically binding proteins and their binding partners.

Abstract: In capillary electrophoresis systems, real-time monitoring and measurement of the electroosmotic flow through a separation capillary is accomplished by coupling the outlet of the separation capillary to an electrically-conductive junction. In one embodiment, this junction is an ion-impermeable or an ion-exchange membrane unit that preferentially exchanges ions having a charge opposite to analyte ions of interest. Within a downstream region of the junction, all axial incremental voltage from the electroosmotic voltage source is terminated, which ensures that downstream electrolyte ion movement is passive, due to active flow created upstream when an incremental axial voltage existed. Upstream electrolyte ion flux is proportional to C.sub.1 .multidot.(.mu..sub.e +.mu..sub.eo), where C.sub.1 is the upstream concentration of the electrolyte ion of interest, .mu..sub.e is the electrolyte electrophoretic mobility, and .mu..sub.eo is the electroosmotic mobility. Downstream, the flux is proportional to C.sub.2 .

Abstract: A novel nucleic acid containing an arabinonucleic acid segment is provided as a probe in nucleic acid assays. The arabinose moiety of the probe can be detected with anti-arabinose antibody-label conjugates.

Abstract: The process for separating the proteinaceous materials from nucleic acids involves contacting a solution containing the proteinaceous materials and nucleic acids with a solid phase extraction material capable of binding proteins to form bound and unbound fractions and then isolating the unbound fraction containing the nucleic acids.

Abstract: A novel nucleic acid, arabinonucleic acid, is provided as a probe in nucleic acid assays. The arabinose moiety of the probe can be detected with anti-arabinose antibody-label conjugates.