Patents by Inventor Charles W. Ragsdale
Charles W. Ragsdale has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20150258547Abstract: Individual temperature control in multiple reactions performed simultaneously in a spatial array such as a multi-well plate is achieved by thermoelectric modules with individual control, with each module supplying heat to or drawing heat from a single region within the array, the region containing either a single reaction vessel or a group of reaction vessels.Type: ApplicationFiled: December 11, 2014Publication date: September 17, 2015Inventors: German Arciniegas, Jeff Ceremony, Daniel Y. Chu, Charles W. Ragsdale
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Patent number: 8945881Abstract: Individual temperature control in multiple reactions performed simultaneously in a spatial array such as a multi-well plate is achieved by thermoelectric modules with individual control, with each module supplying heat to or drawing heat from a single region within the array, the region containing either a single reaction vessel or a group of reaction vessels.Type: GrantFiled: January 5, 2010Date of Patent: February 3, 2015Assignee: Bio-Rad Laboratories, Inc.Inventors: German Arciniegas, Jeff Ceremony, Daniel Y. Chu, Charles W. Ragsdale
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Patent number: 8221299Abstract: Membrane-encased structures such as biological cells, liposomes, and vesicles, are conveyed through one or more channels in a rotating disk for individual exposure to optical elements or to electrodes, for purposes of transfection or flow cytometry. The rotation of the disk serves either to provide centrifugal force to urge the cells against one wall of the channel and in certain embodiments to move the cells through the channels, or to draw cells at preselected times or intervals into the exposure zone, or all three.Type: GrantFiled: June 3, 2009Date of Patent: July 17, 2012Assignee: Bio-Rad Laboratories, Inc.Inventor: Charles W. Ragsdale
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Patent number: 8043838Abstract: An electroporation cuvette is constructed with electroporation electrodes arranged in non-parallel relation to form a gap whose width varies with the location within the cuvette, plus a pair of positioning electrodes that are arranged to cause electrophoretic migration of biological cells within the cuvette according to cell size. Once the cells, suspended in a solution of the impregnant, are distributed in the cuvette by the positioning electrodes, electric field pulses are generated by the non-parallel electroporation electrodes. Because of their distribution in the cuvette, the various cells will experience voltage differentials across their widths that approach uniformity regardless of cell diameter, since the larger cells will be positioned at locations where the gap between the electrodes is greater and the smaller cells at locations where the gap is relatively small while the voltage drop across the entire gap is uniform along the length of the cell.Type: GrantFiled: February 5, 2009Date of Patent: October 25, 2011Assignee: Bio-Rad Laboratories, Inc.Inventor: Charles W. Ragsdale
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Patent number: 8017381Abstract: Electroporation on a plurality of samples of membranous structures is performed in an electroporation well plate that includes a frame that can hold a plurality of well strips to form a two-dimensional array of wells, and a set of well strips, the set containing strips that differ in the number of wells while having the same outer dimensions and hence being interchangeable, thereby allowing the user to select strips appropriate for a given electroporation procedure, and allowing the manufacturer to replace defective strips without rejecting an entire well plate when a small number of wells is found to be defective.Type: GrantFiled: March 8, 2007Date of Patent: September 13, 2011Assignee: Bio-Rad Laboratories, Inc.Inventors: Charles W. Ragsdale, John Morrill
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Patent number: 8008063Abstract: Electroporation is performed on a population of cells, liposomes, vesicles, or other membrane-encased structures with uniform results regardless of size variations within the population, by drawing the membrane-encased structures into micron-sized openings that contain paired electrodes. An electric potential is then imposed between the paired electrodes to permeabilize only that portion of each cell that extends into the openings and resides within the electric field focused in the area between the electrodes.Type: GrantFiled: June 5, 2009Date of Patent: August 30, 2011Assignee: Bio-Rad Laboratories, Inc.Inventor: Charles W. Ragsdale
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Patent number: 7943367Abstract: A chamber that includes electrical contacts and a protective lid with a manually operated release is designed to receive a multi-well electroporation plate and to allow high-throughput electroporation on the well contents with minimal risk of electrical shock to the user and minimal opportunity for sample loss and contamination.Type: GrantFiled: September 19, 2007Date of Patent: May 17, 2011Assignee: Bio-Rad Laboratories, Inc.Inventors: Michelle Collins, Steven Kulisch, Charles W. Ragsdale, Teresa Rubio, Gary Bouchard
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Patent number: 7923238Abstract: Systems, methods and apparatus provide flexible and efficient high throughput electroporation systems. An electrical pulse may be transmitted to any number of channels of a multi-channel sample plate. Drivers can provide the selection of which channels to transmit the electrical pulse. To provide efficient transitions between electrical pulses, discharge circuits provide efficient means achieve a desired voltage.Type: GrantFiled: December 6, 2006Date of Patent: April 12, 2011Assignee: Bio-Rad Laboratories, Inc.Inventor: Charles W. Ragsdale
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Publication number: 20100297753Abstract: Biological cells are transfected by a laser poration process in which the structures are immobilized on a solid surface that is cylindrical in shape, and the cylinder, while immersed in a liquid solution of the transfecting species or otherwise in contact with the solution, is rotated past a stationary laser such that the laser beam spans the entire circumference of the cylinder and all cells immobilized thereon. Axial movement of the cylinder or the laser in addition to the rotational movement brings the entire length of the cylinder within the influence of the laser as well as the cylinder circumference.Type: ApplicationFiled: April 13, 2009Publication date: November 25, 2010Inventor: Charles W. Ragsdale
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Patent number: 7799555Abstract: An electroporator for high-throughput electroporation is constructed with a well plate in which each well has internal electrodes that extend beyond the opening of the well to form contact areas, either as horizontal platforms extending laterally from the well rims or as extended heights of thin electrode plates. The electroporator also includes a lid that contains circuitry and electrical contacts that mate with the exposed contact areas in the well plate. The interchangeability of lids allows the wells to be shocked according to different protocols.Type: GrantFiled: January 25, 2007Date of Patent: September 21, 2010Assignee: Bio-Rad Laboratories, Inc.Inventors: Charles W. Ragsdale, John M. Fuller, Nicholas R. Stephens
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Patent number: 7771933Abstract: Individual temperature control in multiple reactions performed simultaneously in a spatial array such as a multi-well plate is achieved by thermoelectric modules with individual control, with each module supplying heat to or drawing heat from a single region within the array, the region containing either a single reaction vessel or a group of reaction vessels.Type: GrantFiled: May 21, 2004Date of Patent: August 10, 2010Assignee: Bio-Rad Laboratories, Inc.Inventors: German Arciniegas, Jeff Ceremony, Daniel Y. Chu, Charles W. Ragsdale
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Patent number: 7750605Abstract: Systems, methods, apparatus, and circuits for controlling an electrical signal transmitted to a sample load are provided. The electrical signal produced by a capacitor is controlled via a control signal sent to a variable resistance device that is connected in parallel with the sample load. The variable resistance device includes a resistance and a switch in series. The control signal opens and closes the switch, thus providing a variable resistance based on the amount of time the switch is closed.Type: GrantFiled: September 19, 2007Date of Patent: July 6, 2010Assignee: Bio-Rad Laboratories, Inc.Inventor: Charles W. Ragsdale
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Publication number: 20100099581Abstract: Individual temperature control in multiple reactions performed simultaneously in a spatial array such as a multi-well plate is achieved by thermoelectric modules with individual control, with each module supplying heat to or drawing heat from a single region within the array, the region containing either a single reaction vessel or a group of reaction vessels.Type: ApplicationFiled: January 5, 2010Publication date: April 22, 2010Applicant: Bio-Rad Laboratories, Inc.Inventors: German Arciniegas, Jeff Ceremony, Daniel Y. Chu, Charles W. Ragsdale
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Publication number: 20100041122Abstract: Membrane-encased structures such as biological cells, liposomes, and vesicles, are conveyed through one or more channels in a rotating disk for individual exposure to optical elements or to electrodes, for purposes of transfection or flow cytometry. The rotation of the disk serves either to provide centrifugal force to urge the cells against one wall of the channel and in certain embodiments to move the cells through the channels, or to draw cells at preselected times or intervals into the exposure zone, or all three.Type: ApplicationFiled: June 3, 2009Publication date: February 18, 2010Applicant: BIO-RAD LABORATORIES, INC., a corporation of the state of DelawareInventor: Charles W. Ragsdale
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Publication number: 20090317883Abstract: Electroporation is performed on a population of cells, liposomes, vesicles, or other membrane-encased structures with uniform results regardless of size variations within the population, by drawing the membrane-encased structures into micron-sized openings that contain paired electrodes. An electric potential is then imposed between the paired electrodes to permeabilize only that portion of each cell that extends into the openings and resides within the electric field focused in the area between the electrodes.Type: ApplicationFiled: June 5, 2009Publication date: December 24, 2009Applicant: BIO-RAD LABORATORIES, INC.Inventor: Charles W. Ragsdale
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Publication number: 20090305380Abstract: Adherent cells and other membranous structures that are immobilized on a solid surface are transfected by electroporation in which the electric field is produced by a array of closely spaced electrodes positioned above the surface. Each electrode is substantially smaller in at least one lateral dimension than the dimensions of a single cell, and the electrodes in each pair are spaced apart by distances selected such that that a maximum of one cell will reside within the field produced by each pair, and the distance of the electrodes above the surface to which the cells are adherent is small enough to place the cell within the resulting electric field and yet great enough to avoid contact of the electrodes with the cell membrane.Type: ApplicationFiled: May 8, 2009Publication date: December 10, 2009Applicant: BIO-RAD LABORATORIES, INC.Inventor: Charles W. Ragsdale
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Publication number: 20090269851Abstract: Adherent cells on the surface of a disk are transfected by electroporation between coaxial circular cylinders with electrodes on the opposing surfaces on either side of the annular space between the cylinders by placing a buffer solution containing the transfecting species in the annular space over the cell and applying an electric potential between the electrodes.Type: ApplicationFiled: April 16, 2009Publication date: October 29, 2009Applicant: BIO-RAD LABORATORIES, INC. a corporation of the state of DelawareInventor: Charles W. Ragsdale
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Publication number: 20090209017Abstract: An electroporation cuvette is constructed with electroporation electrodes arranged in non-parallel relation to form a gap whose width varies with the location within the cuvette, plus a pair of positioning electrodes that are arranged to cause electrophoretic migration of biological cells within the cuvette according to cell size. Once the cells, suspended in a solution of the impregnant, are distributed in the cuvette by the positioning electrodes, electric field pulses are generated by the non-parallel electroporation electrodes. Because of their distribution in the cuvette, the various cells will experience voltage differentials across their widths that approach uniformity regardless of cell diameter, since the larger cells will be positioned at locations where the gap between the electrodes is greater and the smaller cells at locations where the gap is relatively small while the voltage drop across the entire gap is uniform along the length of the cell.Type: ApplicationFiled: February 5, 2009Publication date: August 20, 2009Applicant: BIO-RAD LABORATORIES, INC. a corporation of the state of DelawareInventor: Charles W. Ragsdale
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Patent number: 7576549Abstract: Systems and methods of measuring resistances of samples to be electroporated and utilizing the measured resistances in the electroporation are provided. During an electrical pulse sent to the sample, a time and a corresponding voltage drop on a known capacitance is measured to determine the sample resistance. A constant voltage may be assumed, and the voltage drop across a known resistance in series with the sample resistance is used to determine the sample resistance. Based on the value of the sample resistance, an electrical pulse may be altered by changing a value of a parallel resistance.Type: GrantFiled: December 6, 2006Date of Patent: August 18, 2009Assignee: Bio-Rad Laboratories, Inc.Inventor: Charles W. Ragsdale
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Publication number: 20090081750Abstract: Biological cells and other membranous structures are transfected in a flow-through system by first rendering the structures magnetically active such that they respond to a magnetic field, suspending the structures in a solution of an exogenous species with which the structures are to be transfected, then placing the suspension in a channel and using a moving magnetization pattern along the channel wall to cause the structures to travel through the channel. Along their path of travel, the structures pass a transmitter that emits transfection energy sufficient to cause the exogenous species in the suspension to permeate the structure membranes and enter the interiors of the structures.Type: ApplicationFiled: January 31, 2008Publication date: March 26, 2009Applicant: BIO-RAD LABORATORIES, INC.Inventors: Charles W. Ragsdale, Teresa Rubio