Abstract: An addressable biologic electrode array includes an array of electrodes disposed on a support, the array of electrodes being selectively addressed and driven using a memory associated with each electrode of the array, the driven electrodes being driven at one of a plurality of stimulus levels by a source of electrical current or voltage external to the array.

Abstract: The present invention relates to methods and devices for separating particles according to size. More specifically, the present invention relates to a microfluidic method and device for the separation of particles according to size using an array comprising a network of gaps, wherein the field flux from each gap divides unequally into subsequent gaps. In one embodiment, the array comprises an ordered array of obstacles in a microfluidic channel, in which the obstacle array is asymmetric with respect to the direction of an applied field.

Abstract: A system utilizing multi-stage traps based on dielectrophoresis. Traps with electrodes arranged transverse to the flow and traps with electrodes arranged parallel to the flow with combinations of direct current and alternating voltage are used to trap, concentrate, separate, and/or purify target particles.

Abstract: An apparatus for carrying out the separation, detection, and/or counting of single molecules at nanometer scale. Molecular separation is achieved by driving single molecules through a microfluidic or nanofluidic medium using programmable and coordinated electric fields. In various embodiments, the fluidic medium is a strip of hydrophilic material on nonconductive hydrophobic surface, a trough produced by parallel strips of hydrophobic nonconductive material on a hydrophilic base, or a covered passageway produced by parallel strips of hydrophobic nonconductive material on a hydrophilic base together with a nonconductive cover on the parallel strips of hydrophobic nonconductive material.

Abstract: An apparatus and methods for determining the dielectrophoretic response of particles under various chemical and physical conditions are disclosed.

Abstract: Electrode arrangement (10) in a microsystem adapted for dielectrophoretic manipulation of particles (30) in a suspension fluid in a channel (21), wherein at least one electrode (11, 11a, 11b, 12) is arranged on a lateral wall of the channel (21), the electrode (11, 11a, 11b, 12) consisting of a plurality of electrode segments adapted to generate at least one field gradient for influencing the movement paths of the particles (30) in the channel (21). In one embodiment of the invention, the particles are moved in the microsystem by exposure to centrifugal and/or gravitational forces.

Abstract: An apparatus is adapted to separate target materials from other materials in a flow containing the target materials and other materials. A dielectrophoretic trap is adapted to receive the target materials and the other materials. At least one electrode system is provided in the trap. The electrode system has a three-dimensional configuration. The electrode system includes a first electrode and a second electrode that are shaped and positioned relative to each such that application of an electrical voltage to the first electrode and the second electrode creates a dielectrophoretic force and said dielectrophoretic force does not reach zero between the first electrode and the second electrode.

Abstract: A method and apparatus are disclosed which characterize the physical properties of particles (21). The apparatus measures the position (22) of particles with respect to the center (32) of electrodes (28) (30) as the dielectrophoretic forces (24) (26) on the particles are modified. A signal source (34) is used to induce dielectrophoretic forces on the particles.

Abstract: A method and apparatus for fractionation of a mixture of particles and for particle analysis are provided, in which LEAPS (“Light-controlled Electrokinetic Assembly of Particles near Surfaces”) is used to fractionate and analyze a plurality of particles suspended in an interface between an electrode and an electrolyte solution. A mixture of particles are fractionated according to their relaxation frequencies, which in turn reflect differences in size or surface composition of the particles. Particles may also be analyzed to determine their physical and chemical properties based on particle relaxation frequency and maximal velocity.

Abstract: Manipulation of DNA and cells/spores using dielectrophoretic (DEP) forces to perform sample preparation protocols for polymerized chain reaction (PCR) based assays for various applications. This is accomplished by movement of particles using sequentially activated dielectrophoretic particle trapping. DEP forces induce a dipole in particles, and these particles can be trapped in non-uniform fields. The particles can be trapped in the high field strength region of one set of electrodes. By switching off this field and switching on an adjacent electrodes, particles can be moved down a channel with little or no flow.

Abstract: A droplet/electrospray device and a liquid chromatography-electrospray system are disclosed. The droplet/electrospray device comprises a substrate defining a channel between an entrance orifice on an injection surface and an exit orifice on an ejection surface, a nozzle defined by a portion recessed from the ejection surface surrounding the exit orifice, and an electrode for application of an electric potential to the substrate to optimize and generate droplets or an electrospray. A plurality of these electrospray devices can be used in the form of an array of miniaturized nozzles. The liquid chromatography-electrospray device comprises a separation substrate defining an introduction channel between an entrance orifice and a reservoir and a separation channel between the reservoir and an exit orifice, the separation channel being populated with separation posts perpendicular to the fluid flow.

Abstract: An apparatus is disclosed which separates particles with different dielectric properties. The apparatus restricts the flow of some particles (27) through a three dimensional array of conductive layers (21) (22) while allowing other particles (25) to flow through. The separation process is controlled by electrical signal generators (23) that are connected to the conductive layers.

Abstract: The present invention is directed to devices and methods for manipulating polarizable analytes via dielectrophoresis to allow for improved detection of target analytes. Microfluidic devices are configured such that the application of a voltage between field-generating electrodes results in the generation of an asymmetric electric field within the device. Some embodiments of the invention provide a physical constriction, and electrically floating conductive material or a combination of the two techniques to generating an asymmetrical field. Using dielectrophoresis, target analytes are concentrated or separated from contaminant analytes and transported to a detection module.

Abstract: Methods and apparatus for discriminating matter in a chamber having an inlet port and an outlet port utilizing dielectrophoresis and field flow fractionation. A carrier medium is introduced into the inlet port and is directed from the inlet port to the outlet port according to a velocity profile. A programmed voltage signal is applied to an electrode element coupled to the chamber to form a dielectrophoretic force on the matter. The dielectrophoretic force is balanced with a gravitational force to displace the matter to positions within said velocity profile in the carrier medium to discriminate the matter. A chamber having a top and bottom outlet port may be utilized to withdraw a first portion of a carrier medium from the top outlet port at a first, controllable fluid flow rate and to withdraw a second portion of the carrier medium from the bottom outlet port at a second, controllable fluid flow rate.

Abstract: A method for concentrating and/or positioning and/or separating particles or cells comprises placing a liquid medium containing the particles and/or cells over a surface having an electrode array associated with the surface, applying an alternating voltage to the electrode array to create an electric field above the surface within the medium to repel the particles or cells from the electrode array and thereby levitate the particles or cells above the surface, within the medium, by negative dielectrophoresis, and heating the liquid medium so as to cause convection currents to circulate within the medium which concentrate or relocate the levitated cells within the medium. Apparatus for concentrating and/or positioning and/or separating particles or cells are also disclosed.

Abstract: Hydrodynamic enhanced dielectrophoretic particle trapping carried out by introducing a side stream into the main stream to squeeze the fluid containing particles close to the electrodes producing the dielelectrophoretic forces. The region of most effective or the strongest forces in the manipulating fields of the electrodes producing the dielectrophoretic forces is close to the electrodes, within 100 &mgr;m from the electrodes. The particle trapping arrangement uses a series of electrodes with an AC field placed between pairs of electrodes, which causes trapping of particles along the edges of the electrodes. By forcing an incoming flow stream containing cells and DNA, for example, close to the electrodes using another flow stream improves the efficiency of the DNA trapping.

Abstract: A method and apparatus are disclosed which precisely characterizes the physical properties of particles (20) (21). The apparatus balances the force of gravity (22) (23) against an induced upward force (24) (25) and measures the elevation (27) (28) of suspended particles. The upward force is generated by a structure (26) containing elements and signals that repel the particles.

Abstract: Methods and apparatus for discriminating matter in a chamber having an inlet port and an outlet port utilizing dielectrophoresis and field flow fractionation. A carrier medium is introduced into the inlet port and is directed from the inlet port to the outlet port according to a velocity profile. A programmed voltage signal is applied to an electrode element coupled to the chamber to form a dielectrophoretic force on the matter. The dielectrophoretic force is balanced with a gravitational force to displace the matter to positions within said velocity profile in the carrier medium to discriminate the matter. A chamber having a top and bottom outlet port may be utilized to withdraw a first portion of a carrier medium from the top outlet port at a first, controllable fluid flow rate and to withdraw a second portion of the carrier medium from the bottom outlet port at a second, controllable fluid flow rate.

Abstract: A device for effecting motion of liquid droplets on a surface through the use of electrostatic field force includes a single substrate on which are disposed a plurality of spaced-apart electrodes. A dielectric material surrounds the electrodes on the substrate. The surface on which the liquid droplets are deposited is fabricated from a material that facilitates motion of the liquid droplets.

Abstract: Microtechnologically prepared component as a flow cytometer. The component contains a preparation area to specifically influence and separate the particles, preferably by means of dielectrophoresis, a measuring channel area for characterizing the particles, and a sorting area for sorting the particles identified in the measuring channel area by means of dielectrophoresis. The sorting includes switching elements which permit active guidance of the particles into two or more subchannels corresponding to the criteria which have been registered in the measuring channel area. By means of a component configured in this way for the use of a flow cytometer, quick and precise sorting of particles, in particular biological cells in a suspension, can be implemented.

Abstract: This invention relates generally to the field of moiety or molecule isolation, detection and manipulation and library synthesis. In particular, the invention provides a bead, which bead comprises: a) a magnetizable substance; and b) an electrically conductive substance or an optical labeling substance. Methods and kits for isolating, detecting and manipulating moieties and synthesizing libraries using the beads are also provided.

Abstract: Methods and apparatuses for providing wall-less virtual channels. The wall-less channels may be regions such as stripes or other patterns that are defined by polar surface coatings. These wall-less channel may be used with polar solvents and defined by polar surface patterning of narrowly separated top and bottom walls of a chamber filled elsewhere by a non-polar partitioning medium. This provides a simple and easy-to-fabricate interface between the micro and macro worlds in which microfluidic processes are separated from the macro world fluid flow by a narrow veil of immiscible fluid across which an exchange of droplets can be controlled electrically.

Abstract: A method and apparatus for analysing very low concentrations of particles present in a fluid sample. The apparatus comprises a support (1) defining and fluid flow channel (9) and a dual electrode array comprising a first electrode means (2) and a second electrode means (3). The first electrode means (2) is energised with an AC voltage of predetermined frequency to attract a predetermined type of particle to the electrode. The voltage is then switched off after a period of time and the second electrode means (3) is energised with an AC voltage of predetermined frequency. After a period of time the voltage is switched off, releasing the particles from the second electrode means for subsequent collection and/or enumeration.

Abstract: An electrode configuration for field cages, especially in microsystems, comprises a large number of electrodes in which an electrical potential can be applied to each end region through a feed region. The end region is arranged to form the field cage and inhomogeneous shielding fields outside the field cage. To reduce thermal convection, the feed region has a strip form whose width is substantially smaller than characteristic dimensions of the end region.

Abstract: This invention relates to devices and methods for performing active, multi-step molecular and biological sample preparation and diagnostic analyses employing immunochemical techniques. It relates generally to bioparticle separation, bioparticle enrichment, and electric field-mediated immunochemical detection on active electronic matrix devices utilizing AC and DC electric fields. More specifically, the invention relates to devices and methods for sample preparation/manipulation, immunoimmobilization, and immunoassays, all of which can be conducted on one or more active electronic chip devices within a single system. These manipulations are useful in a variety of applications, including, for example, detection of pathogenic bacteria and biological warfare agents, point-of-care diagnostics, food or medical product quality control assays, and other biological assays.

Abstract: A device acts as a particle switch to transport and/or re-direct microparticles which are in a fluid suspension. The switch comprises at least three structural branches and the branches may be connected at a common junction. Particles can be transported along the branches as a result of the forces generated along that branch. Particles are transported into or out of the particle switch via the ends of the branches. Particles can be switched from one branch into one of the other branches. Depending on the properties of the particles, the transportation mechanism may be traveling-wave-dielectrophoresis or traveling-wave-electrophoresis.

Abstract: A dielectric gate and related systems and methods for controlling fluid flow. A dielectric gate includes one or more electrodes coupled between an inlet fluid pathway and an outlet fluid pathway. The electrodes are configured to draw fluid from the inlet fluid pathway to the outlet fluid pathway in a precise manner by using dielectric forces arising from electrical signals applied to the electrodes.

Abstract: Magnetic disk drive head/disk stiction is reduced by applying an electrostatic field between the head and the disk as the head dwells in contact with the disk surface. Just before the disk drive begins disk rotation in order that the heads take off, the electrostatic field is removed.

Abstract: A method is disclosed for effecting the concentration of a polar analyte in an alternating electric field. In the method, a relative translation of the polar analyte and an alternating electric field along a translation path is effected. A portion of the polar analyte is then trapped and concentrated in a concentration zone formed by the intersection of the translation path and the alternating electric field. Also disclosed are various devices for carrying out the forgoing method.

Abstract: A method is disclosed for effecting the concentration of a polar analyte in an alternating electric field. In the method, a relative translation of the polar analyte and an alternating electric field along a translation path is effected. A portion of the polar analyte is then trapped and concentrated in a concentration zone formed by the intersection of the translation path and the alternating electric field. Also disclosed are various devices for carrying out the forgoing method.

Abstract: The invention relates to an apparatus and a method for establishing closed dielectrophoretic potential cages and precise displacement thereof, suitable for the manipulation of particles and detection of same. The apparatus comprises a first array of selectively addressable electrodes, lying on a substantially planar substrate and facing toward a second array comprising one electrode. The arrays define the upper and lower bounds of a micro-chamber where particles are placed in liquid suspension. By applying in-phase and counter-phase periodic signals to electrodes, one or more independent potential cages are established which cause particles to be attracted to or repelled from cages according to signal frequency and the dielectric characteristics of the particles and suspending medium. By properly applying voltage signal patterns into arrays, cages may trap one or more particles, thus permitting them to levitate steadily and/or move.

Abstract: Embodiments of methods and devices are disclosed for the manipulation (e.g., concentration, purification, capture, trapping, location, transfer, etc.) of analytes, e.g., biomolecules, with respect to analyte-containing solutions using one or more electric fields.

Abstract: An engineered microparticle and methods and systems relating thereto. The microparticle includes a conductive core and an insulating layer surrounding the conductive core and having a thickness sufficient to render the microparticle responsive to a dielectrophoretic force.

Abstract: A continuous-flow filter/concentrator for separating and/or concentrating particles in a fluid is disclosed. The filter is a three-port device an inlet port, an filter port and a concentrate port. The filter separates particles into two streams by the ratio of their dielectrophoretic mobility to their electrokinetic, advective, or diffusive mobility if the dominant transport mechanism is electrokinesis, advection, or diffusion, respectively.

Abstract: An adaptive alignment technique provides precise control and active positioning in, preferably, two-dimensions of sub-millimeter-sized objects such as, in one application, spherical mircolenses through the application of electrophoretic forces in a microfluidic wells. A lithographically patterned microfluidic well and electrodes can be addressed to position or align a spherical microlens to a corresponding laser light beam. The motion of the microlens is preferably controlled using CMOS compatible voltages (3V-1 &mgr;A) that are preferably applied to opposite electrodes in the microfluidic well, creating an electrical field in a well solution. By applying voltages to opposed electrode pairs, movement of spherical microlenses with sizes ranging from, most typically, 0.87 &mgr;m to 40 &mgr;m in directions parallel to the electrode surface is realized. Under a bias of 3 volts, the microspheres have electrophoretic velocities ranging from 13 to 16 &mgr;m/s.

Abstract: Devices and methods utilizing dielectric pumping and variable dielectric pumping to move fluids through microchannels. Two fluids having dissimilar dielectric constants form an interface that is positioned between two electrodes in order to move the interface and therefore the fluids. Dielectric pumping and variable dielectric pumping may be used to move fluids in miniaturized analytical packages containing microchannels in which forces created by surface tension predominate over the gravitational force.

Abstract: The present invention generally provides microfluidic devices and systems that utilize electrokinetic material transport systems to selectively control and direct the transport of materials through and among complex arrangements of integrated, interconnected microscale channels disposed within integrated body structures.

Abstract: A microfluidic microchip includes a channel structure having a delivery channel connected in a substance conductive manner to a separation channel. Laterally offset discharge channels are at connection points displaced from a connection point between the delivery and separation channels. Between the connection points on the one hand and the connection point on the other are channel sections having concordant channel lengths. By imposing suitable electrical potentials along these channel sections, the filling volumes present in the channel sections are satisfactorily homogenous after a certain period of time to form a representative part of a substance specimen. Substance volume units are formed in these channel sections. The lengths of the volume units are determined exclusively by the lengths of the channel sections. Pulse-shaped substance volume sequences are injected into the separation channel.

Abstract: A method and apparatus for fractionation of a mixture of particles and for particle analysis are provided, in which LEAPS (“Light-controlled Electrokinetic Assembly of Particles near Surfaces”) is used to fractionate and analyze a plurality of particles suspended in an interface between an electrode and an electrolyte solution. A mixture of particles are fractionated according to their relaxation frequencies, which in turn reflect differences in size or surface composition of the particles. Particles may also be analyzed to determine their physical and chemical properties based on particle relaxation frequency and maximal velocity.

Abstract: An apparatus is adapted to separate target materials from other materials in a flow containing the target materials and other materials. A dielectrophoretic trap is adapted to receive the target materials and the other materials. At least one electrode system is provided in the trap. The electrode system has a three-dimensional configuration. The electrode system includes a first electrode and a second electrode that are shaped and positioned relative to each such that application of an electrical voltage to the first electrode and the second electrode creates a dielectrophoretic force and said dielectrophoretic force does not reach zero between the first electrode and the second electrode.

Abstract: A system utilizing multi-stage traps based on dielectrophoresis. Traps with electrodes arranged transverse to the flow and traps with electrodes arranged parallel to the flow with combinations of direct current and alternating voltage are used to trap, concentrate, separate, and/or purify target particles.

Abstract: The invention relates to an apparatus and a method for establishing closed dielectrophoretic potential cages and precise displacement thereof, suitable for the manipulation of particles and detection of same. The apparatus comprises a first array of selectively addressable electrodes, lying on a substantially planar substrate and facing toward a second array comprising one electrode. The arrays define the upper and lower bounds of a micro-chamber where particles are placed in liquid suspension. By applying in-phase and counter-phase periodic signals to electrodes, one or more independent potential cages are established which cause particles to be attracted to or repelled from cages according to signal frequency and the dielectric characteristics of the particles and suspending medium. By properly applying voltage signal patterns into arrays, cages may trap one or more particles, thus permitting them to levitate steadily and/or move.

Abstract: The present invention generally provides microfluidic devices and systems that utilize electrokinetic material transport systems to selectively control and direct the transport of materials through and among complex arrangements of integrated, interconnected microscale channels disposed within integrated body structures.

Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. In one aspect, a method is provided for analyzing particles by electrokinetically moving the particles and subjecting the particles to optical forces for analysis.

Abstract: In a method for positioning or controlling the motion of an object in a multi-electrode arrangement for forming a field cage, the basic potentials for driving the electrodes are modulated with drive potentials in such a way that the object position in the field cage changes in relation to a predetermined position or path. A device for arranging objects at predetermined positions in a multi-electrode arrangement has a switching device by which basic potentials, produced by generator means, can be modulated according to predetermined drive potentials (FIG. 1).

Abstract: Apparatus and methods are provided for interacting light with particles, including but not limited to biological matter such as cells, in unique and highly useful ways. Optophoresis consists of subjecting particles to various optical forces, especially optical gradient forces, and more particularly moving optical gradient forces, so as to obtain useful results. In biology, this technology represents a practical approach to probing the inner workings of a living cell, preferably without any dyes, labels or other markers. In one aspect, a method is provided for reducing forces between a particle and a surface in a system for optically moving particles by providing particles adjacent a first surface, subjecting the particles to a first light intensity pattern to effect sorting of the particles, and subjecting the particles to a second force in an amount and direction to reduce the interaction between the particle and the surface.

Abstract: Manipulation of DNA and cells/spores using dielectrophoretic (DEP) forces to perform sample preparation protocols for polymerized chain reaction (PCR) based assays for various applications. This is accomplished by movement of particles using sequentially activated dielectrophoretic particle trapping. DEP forces induce a dipole in particles, and these particles can be trapped in non-uniform fields. The particles can be trapped in the high field strength region of one set of electrodes. By switching off this field and switching on an adjacent electrodes, particles can be moved down a channel with little or no flow.

Abstract: Impedance measurements between the electrodes in an electric field is utilized to detect the presence of pathogens trapped in the electric field. Since particles trapped in a field using the dielectiphoretic force changes the impedance between the electrodes by changing the dielectric material between the electrodes, the degree of particle trapping can be determined by measuring the impedance. This measurement is used to determine if sufficient pathogen have been collected to analyze further or potentially to identify the pathogen.

Abstract: We have performed separation of bacterial and cancer cells from peripheral human blood in microfabricated electronic chips by dielectrophoresis. The isolated cells were examined by staining the nuclei with fluorescent dye followed by laser induced fluorescence imaging. We have also released DNA and RNA from the isolated cells electronically and detected specific marker sequences by DNA amplification followed by electronic hybridization to immobilized capture probes. Efforts towards the construction of a “laboratory-on-a-chip” system are presented which involves the selection of DNA probes, dyes, reagents and prototyping of the fully integrated portable instrument.

Abstract: The present invention generally provides microfluidic devices and systems that utilize electrokinetic material transport systems to selectively control and direct the transport of materials through and among complex arrangements of integrated, interconnected microscale channels disposed within integrated body structures. Channels are sized and positioned to provide equal resistance in different paths.