157 results about "Dielectrophoretic force" patented technology

A dielectrophoretic display is shifted from a low frequency closed state to a high frequency open state via at least one, and preferably several, intermediate frequency states; the use of such multiple frequency steps reduces flicker during the transition. A second type of dielectrophoretic display has a light-transmissive electrode through which the dielectrophoretic medium can be viewed and a conductor connected to the light-transmissive electrode at several points to reduce voltage variations within the light-transmissive electrode.

A dielectrophoretic display has a substrate having walls defining a cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface. A fluid is contained within the cavity; and a plurality of particles are present in the fluid. There is applied to the substrate an electric field effective to cause dielectrophoretic movement of the particles so that the particles occupy only a minor proportion of the viewing surface.

A dielectrophoretic display has a substrate having walls defining a cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface. A fluid is contained within the cavity; and a plurality of particles are present in the fluid. There is applied to the substrate an electric field effective to cause dielectrophoretic movement of the particles so that the particles occupy only a minor proportion of the viewing surface.

This invention relates generally to the field of field-flow-fractionation. In particular, the invention provides apparatuses and methods for the discrimination of matters utilizing acoustic force, or utilizing acoustic force with electrophoretic or dielectrophoretic force, in field flow fractionation.

A new class of microwires and a method for their assembly from suspensions of metallic nanoparticles in water under the influence of dielectrophoretic forces. The wires are formed in the gaps between planar electrodes in an alternating current (AC), allowing manipulation of the particles without the interference of electro-osmotic and electro-chemical effects resent in direct current (DC) systems. The structures created cover a new size domain of microwires of micrometer diameter and millimeter to centimeter length, closing the gap between tradition metallic wires and the more recently synthesized nanowires and carbon tubes. The wires have good Ohmic conductance and their thickness, conductivity, and fractal dimension can be controlled by varying the frequency and voltage of the applied field. The formation of such self-assembled structures can be used in miniaturization of electrical circuits for application in sensors, memory elements, and wet electronic circuits, such as electrically readable bioarrays and biological-electronic interfaces.

The present invention has an object of providing a method by which two kinds or more of molecules can be separated each other by using dielectrophoretic forces. The present invention comprises two methods. The first method is a method comprising forming a complex substance of a “specific molecule” containing in a sample, and a “substance capable of changing dielectrophoretic properties of the specific molecule”, which binds to the “specific molecule” contained therein, and thereby separating the complex substance and the molecules other than the specific molecule in the sample from each other. The second method is a method comprising placing a solution in which two kinds or more of molecules are dissolved under a strong electric field strength, that is, under a nonuniform electric field having an electric field strength of 500 KV / m or higher, by using dielectrophoretic forces.

Methods and apparatuses for discriminating matter utilizing dielectrophoresis combined with magnetophoresis. A sample having one or more constituents is injected into an inlet port of a chamber. A carrier medium flow is initiated at the inlet port to establish a flow within the chamber. A dielectrophoretic force is generated to act on the constituents of the sample. A magnetophoretic force is generated to act on the constituents of the sample. The dielectrophoretic force and magnetophoretic forces are balanced to position the constituents within the chamber. The constituents are then collected at one or more outlet ports of the chamber according to the dielectric and magnetic characteristics of the constituents. The constituents may be collected as a function of time-of-exit from the chamber and / or position within the chamber.

Described herein are single-sided lateral-field optoelectronic tweezers (LOET) devices which use photosensitive electrode arrays to create optically-induced dielectrophoretic forces in an electric field that is parallel to the plane of the device. In addition, phototransistor-based optoelectronic tweezers (PhOET) devices are described that allow for optoelectronic tweezers (OET) operation in high-conductivity physiological buffer and cell culture media.

To provide An electrode for a dielectrophoretic apparatus in which a background detected by reflecting an excited light on an electrode present under the substance (molecule) is reduced and an S / N ratio is enhanced. Also, there is provided an dielectrophoretic apparatus, in an apparatus in which a liquid containing substances to be separated is present in a non-uniform electric field formed by a dielectrophoretic electrode, and separation is carried out by a dielectrophoretic force exerting on the substances, wherein the collecting ability of substances is enhanced. The present invention is characterized in that a vacant space is provided in an electrode whereby substances subjected to influence by a negative dielectrophoretic force can be concentrated in said vacant space of an electrode, or above or below portion of the space.

The present invention relates to an apparatus and methods of separating particles or cells according to their sizes, wherein the size of each of the particles or cells is characterized by a corresponding diameter. In one embodiment, the method includes the steps of providing a microchannel structure having at least one channel that is defined by a first sidewall and a second, opposite sidewall and has an insulating protrusion formed on one of the first sidewall and the second, opposite sidewall, introducing a plurality of particles or cells in a liquid medium into the at least one channel, and generating a non-uniform electrical field in the at least one channel such that when the plurality of particles or cells passes by the insulating protrusion, the plurality of particles or cells each receives a dielectrophoretic force proportional to its diameters, thereby being separable according to their sizes. The method further has the step of collecting particles or cells after the separation of particles or cells.

A biological sample immobilizing apparatus is provided, comprising a holding unit which holds a biological sample, a pair of electrodes which allows a dielectrophoretic force to act on the biological sample to move the biological sample to the holding unit, and a power source which applies an AC voltage to the pair of electrodes. Accordingly, a plurality of components contained in the biological sample can be conveniently separated into individuals one by one and respective genes thereof can be analyzed one by one quickly and simultaneously, while providing a high density and being miniaturized.

A biochip (100) for lysing and / or cell separation is formed to provide a sealed chamber for biological fluid. A conductive layer (140) bonded between upper (130) and lower (150) insulating layers is etched to form a microfluidic channel (250) between two electrodes (190, 200). The microfluidic channel connects a fluid inlet (11) and fluid outlet (120). The electrodes (190, 200) form an un-even electric field in the channel (250) to generate a dielectrophoretic force on the cells / particles within the sample fluid. A voltage source applies a suitable voltage to separate and / or lyse cells within the fluid.

Methods are provided for the fabrication of microscale, including micron and sub-micron scale, including nanoscale, devices. Electronic transport of movable component devices is utilized through a fluidic medium to effect transport to a desired target location on a substrate or motherboard. Forces include electrophoretic force, electroosmotic force, electrostatic force and / or dielectrophoretic force. In the preferred embodiment, free field electroosmotic forces are utilized either alone, or in conjunction with, other forces. These forces may be used singly or in combination, as well as in conjunction with yet other forces, such as fluidic forces, mechanical forces or thermal convective forces. Transport may be effected through the use of driving electrodes so as to transport the component device to yet other connection electrodes. In certain embodiments, the component devices may be attached to the target device using a solder reflow step.

Optically active glazing comprising two parallel plates of glass or the like that define between them a closed volume containing dielectric particles in suspension in a fluid, and electrodes formed on the plates and connected to an electrical power supply for moving and organizing the particles by means of dielectrophoretic forces and of interactions between particles.

Methods and apparatus for the micro-scale, dielectrophoretic separation of particles are provided. Fluid suspensions of particles are sorted and separated by dielectrophoretic separation chambers that have at least two consecutive, electrically coupled planar electrodes separated by a gap in a fluid flow channel. The gap distance as well as applied potential can be used to control the dielectrophoretic forces generated. Using consecutive, electrically coupled electrodes rather than electrically coupled opposing electrodes facilitates higher flow volumes and rates. The methods and apparatus can be used, for example, to sort living, damaged, diseased, and / or dead cells and functionalized or ligand-bound polymer beads for subsequent identification and / or analysis.

First entities consisting in cells or microorganisms (BIO) and second entities consisting in compounds or compound units, carried typically by microbeads (BEAD), are trapped selectively within closed movable potential cages (S1) by means of dielectrophoretic force generated by mutually opposed electrodes (M1, M2). The cages are set in relative motion so as to bring about the interaction of selected first and second entities, causing the cages containing them to fuse, whereupon results are obtained preferably by reinstating the original cages and / or observing previously empty adjacent cages. The procedure takes place in a device (DE) with two separate chambers (F, FL) connected one to the other by way of a narrow passage (D) and finished with respective selectively controllable inlets and outlets (I1, I2; O1, O2) through which a liquid or semi-liquid buffer (L) can be pumped in or out.

Methods for optically trapping and manipulating micro- and nano-sized particles by using light to induce localized surface plasmon resonance on metallic surface of a substrate. The method includes the steps of contacting a substrate with a medium having particles suspended therein; focusing a beam of coherent light onto the substrate such that the beam induces surface plasmon resonance; and trapping at least one of the suspended particles using a light induced dielectrophoresis force generated by the surface plasmon resonance.

The invention discloses a micro-liquid-drop transportation method. The method takes a y-shaped cut lithium niobate wafer as a chip substrate and takes a dielectrophoresis force generated by irradiating the lithium niobate wafer through laser focusing as a driving force of micro-liquid-drops; and the micro-liquid-drops are driven by scanning motion of laser focusing light spots on the lithium niobate wafer to be transported according to a random two-dimensional path. According to the method disclosed by the invention, the structure of a needed chip is simple, and the transportation motion of the micro-liquid-drops is accurately and flexibly adjusted and controlled through controlling a light spot scanning speed and laser power. Furthermore, the method also has the characteristics of non-local light response, double-liquid-drop synchronous transportation and the like. The technology can be used for transporting micro-medicaments and fluid samples in biological, chemical and medical analysis processes, and has very important meanings on the development of fields including biological medicine, drug diagnosis, environment monitoring and molecular biology and the like.

Rapid, size-based, deposition of particles from liquid suspension is accomplished using a nonuniform electric field created by coplanar microelectrode strips patterned on an insulating substrate. The scheme uses the dielectrophoretic force both to distribute aqueous liquid containing particles and, simultaneously, to separate the particles. Size-based separation is found within nanoliter droplets formed along the structure after voltage removal. Bioparticles or macromolecules of similar size can also be separated based on subtle differences in dielectric property, by controlling the frequency of the AC current supplied to the electrodes.

The present invention is notably directed to a microfluidic chip (1, 1a) comprising: a flow path (22) defined by a hydrophilic surface; a liquid input (24, 24a, 24b) on one side of the flow path; at least one electrical circuit (62), hereafter DEP circuit, comprising at least one pair of dielectrophoretic electrodes (E21, E22), hereafter DEP electrodes, wherein: each of the DEP electrodes extends transverse to the flow path; and the DEP circuit is configured to generate a dielectrophoretic force, hereafter DEP force, at the level of the DEP electrodes. The chip may further include one or more electroosmotic circuits. The present invention is further directed to methods of operation of such a microfluidic chip.

A method for concentrating or partly separating particles of a selected species from a liquid or fluid containing these particles and flowing in a channel, and for determining if the selected species particle is present in the liquid or fluid. A time varying electrical field E, having a root-mean-square intensity E2rms with a non-zero gradient in a direction transverse to the liquid or fluid flow direction, is produced by a nanostructure electrode array, with a very high magnitude gradient near exposed electrode tips. A dielectrophoresis force causes the selected particles to accumulate near the electrode tips, if the medium and selected particles have substantially different dielectric constants. An insulating material surrounds most of each of the nanostructure electrodes, and a region of the insulating material surface is functionalized to promote attachment of the selected species particles to the surface. An electrical property value Z(meas) is measured at the functionalized surface and is compared with a reference value Z(ref) to determine if the selected species particles are attached to the functionalized surface.

An apparatus and method for separating an analyte from a test sample, such as bacteria from blood components, based on their dielectric properties, localizing or condensing the analyte, flushing substantially all remaining waste products from the test sample, and detecting low concentrations of the analyte. Species movement is caused by a module array imparting opposing dielectrophoretic forces. The module array includes a plurality of microfluidic channels with connecting microfluidic waste channels for directing undesired material away from the analyte. An electric field is applied causing a positive dielectrophoretic force to the analyte to capture the analyte. The Clausius-Mossotti factor of the analyte is changed by flushing the analyte with a reference solution, which causes a negative dielectrophoretic force to facilitate release of the analyte. A field effect nanowire or nanoribbon sensor detects the analyte after capture.

An apparatus for separating an analyte from a test sample, such as bacteria from blood components, based on their dielectric properties, localizing or condensing the analyte, flushing substantially all remaining waste products from the test sample, and detecting low concentrations of the analyte. The module array includes a plurality of microfluidic channels with connecting microfluidic waste channels for directing undesired material away from the analyte. An electric field is applied causing a positive dielectrophoretic force to the analyte to capture the analyte. The electric field is applied to at least one electrode having a plurality of concentric rings or concentric arcs extending radially outwards from a center point, electrically connected to a voltage source such that when voltage is applied to the at least one electrode, the concentric rings or concentric arcs alternate in voltage potential.

The invention discloses a method for monitoring the concentration of micro-particle in air by combining a dielectrophoresis force principle and a quartz crystal microbalance technology. The method comprises the following steps: quantitatively conveying the air into an electrolyte solution so that micro-particles in the air are dispersed in the electrolyte solution; measuring the mass of the micro-particles, which are dispersed in the electrolyte solution and in a certain radius range, by utilizing dielectrophoresis force collection and deposition through a quartz crystal microbalance; and calculating and processing to obtain the concentration of the micro-particles, in the certain radius range, in the air. The invention further discloses a system designed based on the method, and the instantaneity and the complete automation of the monitoring of the micro-particles in the air are realized. The system comprises an air sampling part, a detection part, a data processing part and a manipulation part, wherein the air sampling part is used for collecting the air and measuring the sampling volume; the detection part is used for separating and measuring the mass of the micro-particles in different radius ranges; the data processing part is used for collecting data and finishing the concentration calculation; and the manipulation part is used for driving and controlling all the parts of the system to operate.