Other

The United States of America As Represented by the Administrator of the

Universities Space Research Association

Robert S Snyder

Percy H Rhodes

James C Fletcher

J Milton Harris

Daniel C Carter

Lawrence James DeLucas

Marc L Pusey

Teresa Y Miller

Blair J Herren

Charles E Bugg

Vaughn H Yost

Fred L Suddath

Hans U Walter

James M Van Alstine

Steve Shafer

Blair Herren

An apparatus and method is described for obtaining a preparative-scale, free-fluid electrophoretic separator with high resolution as well as an analytical capability commensurate with capillary zone electrophoresis. The electrophoretic focusing apparatus and method of the present invention features a separation chamber bounded by planar precision-pore, insulated screens, a plurality of purge chambers, a plurality of electrode chambers, and a plurality of pump means. The separation device of the invention is capable of high speed of separation and short residency of sample through the use of high voltage gradients which are produced by relatively low voltages applied across the narrow chamber dimensions. The present apparatus and method thus achieves high resolution of separation in an analytical or a preparative mode through a practically unlimited scale-up potential, and controls the adverse effects of Joule heating and electrohydrodynamics on the electrophoretic separation procedure.

Method and apparatus for electrophoretic focusing

An electrophoretic focusing apparatus and method is provided for obtaining a preparative-scale, free-fluid electrophoretic separator with high resolution and an analytical capability commensurate with capillary zone electrophoresis. The present invention combines features of electrophoresis and isoelectric focusing to accomplish large scale purifications and fractionations not previously possible, and features a separation chamber bounded by precision-pore insulated screens, a plurality of purge chambers, a plurality of electrode chambers, and a plurality of pump means. The device of the invention is capable of high speed of separation through the use of high voltage gradients produced by low voltages applied across the narrow chamber. The present invention is also highly flexible, with operation in either a constant electric field, continuous flow mode or in a linearly varying electric field, batch mode, and both modes permit scanning of the sample fraction content and display in a conventional histogram format.

Method for electrophoretic focusing

An apparatus and method is provided for obtaining a preparative-scale, free-fluid electrophoretic separator with high resolution as well as an analytical capability commensurate with capillary zone electrophoresis. The electrophoretic focusing apparatus and method of the present invention combines features of electrophoresis and isoelectric focusing to accomplish large scale purifications and fractionations that have not previously been possible, and features a separation chamber bounded by precision-pore, insulated screens, a plurality of purge chambers, a plurality of electrode chambers, and a plurality of pump means. The separation device of the invention is capable of high speed of separation and short residency of sample through the use of high voltage gradients which are produced by relatively low voltages applied across the narrow chamber dimensions. The present invention is also highly flexible, with operation in either a constant electric field, continuous flow mode or in a linearly varying electric field, batch mode, and both modes permit scanning of the sample fraction content and display in a conventional histogram format. The present apparatus and method thus achieves high resolution of separation in an analytical or a preparative mode through a practically unlimited scale-up potential, and controls the adverse effects of Joule heating and electrohydrodynamics on the electrophoretic separation procedure.

An apparatus and method is provided for obtaining a preparative-scale, free-fluid electrophoretic separator with high resolution as well as an analytical capability commensurate with capillary zone electrophoresis. The electrophoretic focusing apparatus and method of the present invention combines features of electrophoresis and isoelectric focusing to accomplish large scale purifications and fractionations that have not previously been possible, and features a separation chamber bounded by planar porous insulated screens, a plurality of purge chambers, a plurality of electrode chambers, and a plurality of pump means. The separation device of the invention is capable of high speed of separation and short residency of sample through the use of high voltage gradients which are produced by relatively low voltages applied across the narrow chamber dimensions. The present invention is also highly flexible, with operation in either a constant electric field, continuous flow mode or in a linearly varying electric field, batch mode, and both modes permit scanning of the sample fraction content and display in a conventional histogram format. The present apparatus and method thus achieves high resolution of separation in an analytical or a preparative mode through a practically unlimited scale-up potential, and controls the adverse effects of Joule heating and electrohydrodynamics on the electrophoretic separation procedure.

A novel free-fluid electrophoresis system applicable to both 'analytical' and 'preparative' separations combines the advantages of electrophoresis with those of automated liquid chromatography. The system attains plug flow of sample molecules within a separation column that has a sufficiently small diameter to avoid uncorrected convective dispersions and a sufficiently large diameter to ensure adequate preparative throughput. Sample molecules are introduced by liquid chromatographic-type injection mechanisms and moved to the separation column by means of a highly accurate, low-pressure pumping system. A novel pressure detector monitors pressure across the column during the electrophoretic separation. When the pressure across the column is zero, electroosmotic flow within the column exactly balances pump-induced flow so that there is no lateral dispersion of the separating sample molecules (i.e., plug flow is achieved). The pressure detector is monitored by a computer that controls either the pump and/or the electrophoretic power supply to maintain balance between the pressure-driven flow and the electroosmotically driven flow; alternatively carefully controlled departures from the balance can be maintained to increase throughput. The separated sample molecules can be optically detected within the separation column. When the separated sample molecules leave the separation column, they can be collected using fraction collection equipment similar to that used in liquid chromatography. The use of programmed nonuniform voltage and temperature fields allow for practically unlimited scale-up potential.

Chromatography-format fluid electrophoresis

A clinostat for simulating microgravity on cell systems carried in a fiber fixedly mounted in a rotatable culture vessel. The clinostat is rotated horizontally along its longitudinal axis to simulate microgravity or vertically as a control response. Cells are injected into the fiber and the ends of the fiber are sealed and secured to spaced end pieces of a fiber holder assembly which consists of the end pieces, a hollow fiber, a culture vessel and a tension spring with three alignment pins. The tension spring is positioned around the culture vessel with its ends abutting the end pieces and the alignment pins extend between the end pieces for alignment of the spring. After the fiber is secured, the spring is decompressed to maintain tension on the fiber while it is being rotated. This assures that the fiber remains aligned along the axis of rotation. The fiber assembly is placed in the culture vessel and culture medium is added. The culture vessel is then inserted into the rotatable portion of the clinostat and subjected to rotate at selected rpms. The internal diameter of the hollow fiber determines the distance the cells are from the axis of rotation.

Hollow fiber clinostat for simulating microgravity in cell culture

This invention relates to a crystal growth apparatus (10) generally used for growing protein crystals wherein a vapor diffusion method is used for growing the crystals. In this apparatus, a precipitating solution and a solution containing dissolved crystalline material are stored in separate vials (12, 14), each having a resilient diaphragm (28) across one end and an opening (24) with a puncturable septum (26) thereacross at an opposite end. The vials are placed in receptacles (30) having a manifold (41) with a manifold diaphragm (42) in contact with the vial diaphragm at one end of the receptacle and a hollow needle (36) for puncturing the septum at the other end of the manifold. The needles of each vial communicate with a ball mixer (40) that mixes the precipitate and protein solutions and directs the mixed solution to a drop support (64) disposed in a crystal growth chamber (16), the drop support being a tube with an inner bevelled surface (66) that provides more support for the drop (68) than the tubes of the prior art. A sealable storage region (70) intermediate the drop support and mixer provides storage of the drop (68) and the grown crystals.

Drop deployment system for crystal growth apparatus

A macromolecular crystal growing system especially designed for growing crystals in the low gravity of space as well as the gravity of earth includes at least one tray assembly, a carrier assembly which receives the tray, and a refrigeration-incubation module in which the carrier assembly is received. The tray assembly includes a plurality of sealed chambers with a plastic syringe and a plug means for the double tip of the syringe provided therein. Ganging mechanisms operate the syringes and plugs simultaneously in a precise and smooth operation. Preferably, the tray assemblies are mounted on ball bearing slides for smooth operation in inserting and removing the tray assemblies into the carrier assembly. The plugging mechanism also includes a loading control mechanism. A mechanism for leaving a syringe unplugged is also provided.

Macromolecular crystal growing system

A moving wall, continuous flow electrophoresis apparatus (10) having a frame (18) with an electrophoresis chamber (12) mounted between a pair of synchronously driven belt walls (14, 16). The frame (18), and thus the chamber (12), is supported between the belt walls (14, 16) and is angularly positionable with respect to the direction of belt travel. The belts are stored on supply reels (98, 156) at one end of the device and are taken up on driven reels (94, 132) at the other end, thus constantly exposing new belt material within the chamber.

Moving wall, continuous flow electronphoresis apparatus

A method for eliminating or controlling electroosmosis and other zeta potential related phenomena in electrophoresis comprising conducting electrophoresis employing electrophoretic surfaces coated with covalently bound hydrophilic, neutral polymers is described. An electrophoretic chamber for eliminating or controlling electroosmosis and other zeta potential related phenomena in electrophoresis comprising electrophoretic surfaces coated with covalently bound hydrophilic, neutral polymers, is also disclosed as well as particles exhibiting controlled electrophoretic mobility. The method and electrophoretic chamber not only eliminate electroosmosis, but allow for specific control of electroosmosis. The coated electrophoretic surface is stable relative to prior art coatings and over a broad range of pH. The point of optical focus for accurate mobility measurements is increased from a narrow stationary level to the entire chamber, facilitating accurate measurements by mechanical means. The method also reduces or eliminates assymetric fluid flows due to electroosmosis in electrophoresis chambers of square or rectangular cross-section.

Polymer-coated surfaces to control surface zeta potential

An electrophoresis device is disclosed for separating cellular particles of a sample substance into fractionated streams of different cellular species wherein the device includes a casing 10 having a distribution chamber A, separation chamber B, and collection chamber C. The electrode chambers 34 are separated from the separation chamber interior 16 by means of passages 50 and 48 such that flow variations and membrane variations around the slotted portion 34a of the electrode chamber do not enduce flow perturbations into the laminar buffer curtain flowing in the separation chamber. The cellular particles of the sample are separated under the influence of the electrical field and the separation chamber 16 and separated into streams of different cellular species. The streams of separated cells enter a partition array 52 in the collection chamber C and are fractionated and collected therein.

Electrophoresis device

The method of refining, or growing, bulk single crystals in which the base material is suspended, positioned, and shaped as a containerless melt by wetting forces in an environment substantially free of gravity.

Growing community of inventors

Huntsville, AL, United States of America

Robert S Snyder