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  Optoelectronic probeUSPTO Application #: 20060175192Title: Optoelectronic probe Abstract: The present invention, referred to as optoelectronic probe, concerns a novel apparatus and method for characterization and micromanipulation of particles or biomolecules in an electrolyte solution. Electric fields, which include both time constant and time-varying components, are applied to a thin insulating layer covered, lightly doped semiconductor material. Illumination injects carriers into the insulator/semiconductor interface to compensate the leaking minority carrier current and maintain an inversion layer, which works as an electrode to control the particle movements. A particle array, or even a single cell, can be assembled in, or moved along with the inversion layer electrode, which is induced by illumination. Furthermore, an impedance analyzer is utilized to characterize the trapped particles, or single cell. The present invention has numerous uses, such as bio-chemical analysis systems, and nanosize structures assembly for electronic or optical devices. (end of abstract)
Agent: Haian Lin - Bethelehem, PA, US Inventor: Haian Lin USPTO Applicaton #: 20060175192 - Class: 204194000 (USPTO) Related Patent Categories: Chemistry: Electrical And Wave Energy, Apparatus, Electrolytic The Patent Description & Claims data below is from USPTO Patent Application 20060175192. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not Applicable STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX [0003] Not Applicable BACKGROUND OF THE INVENTION Field of Invention [0004] The present invention is directed generally to methods and apparatus based on optoelectronic effect, electro/dielectro-phoresis, and impedance spectroscopy, in order to trap, move, deform and characterize particles, such as cells, molecules, any type of colloids, any of inorganic and bio-organic substances, beads, as well as pucks and like small things. "Optoelectronic Probe" refers to the invention described herein. BACKGROUND OF THE INVENTION [0005] I. Optical Tweezers [0006] The manipulation of micro- or nano-size particles is considered as the key for the new generation of photonic, optoelectronic, and electronic devices, as well as biochemical analysis systems. Optical tweezers is one of the most unique invention in this area and was first successfully demonstrated by A. Ashkin et al. in pioneering works in 1985. (Ashkin, A.; Dziedzic, J. M., "Observation of Radiation-Pressure Trapping of Particles by Alternating Light Beams", Phys. Rev. Lett. 54, pp 1245-1248 (1985)) The technique of optical tweezers is based on the forces of radiation pressure. These are dipole- or gradient-forces arising from the momentum of the light itself. To make these forces large enough to accelerate, decelerate, deflect, guide, and even stably trap small particles, one has to use continuous wave coherent laser beams to achieve the high intensities and high intensity gradients. Combined with other techniques, optical tweezers can also be a unique tool to characterize the trapped particle. For example, laser fluorescence techniques give increased opportunities to a proper identification of different types of biological objects or labeling. [0007] Although the Optical Tweezers is a very powerful tool, it also has its limitations, such as: 1) that the trapping zone is rather small (on the order of the light wavelength); and 2) focusing the beam leads to very high intensities that can endanger the integrity of biological objects. [0008] II. Electrophoresis/Dielectrophoresis Based Arts [0009] When it is exposed to an electrical field, a charged particle will experience a force and the resulting motion is called as electrophoresis (EP). A neutral particle can also be polarized under electrical field. If a nonuniform direct current (DC) or alternating current (AC) field exists, the polarized particle will move towards or away from regions of high electric-field intensity. This motion is a result of interaction between the field and dipole moment induced in a particle and is called dielectrophoresis (DEP). [0010] The dielectrophoretic force on the particle varies with the frequency of the applied electric field. At the low frequency, the polarity of the dielectrophoretic force on the particle depends on the conductivity difference between the particles and electrolyte. On the other hand, at the high frequency the polarity of the dielectrophoretic force on the particle depends on the permettivity difference between the particles and electrolyte. If the particle is more conductive than the electrolyte around it, the dipole aligns with the field and the force acts up the field gradient towards the region of highest electric field. This effect is called positive dielectrophoresis (PDEP). If the particle is less polarisable than the electrolyte, the dipole aligns against the field and the particle is repelled from regions of high electric field (Hughes, "AC Electrokinetics: Applications for Nanotechnology", Nanotechnology, 11, pages 124-132, (2000)).This effect is called negative dielectrophoresis (NDEP). [0011] Recently, both EP and DEP have captured much interest because they are effective ways to trap, move, deform and separate particles ranging from colloidals to DNA strands and biological cells (Huang, Y; Ewalt, K. L; et al; "Electric Manipulation of Bioparticles and Macromolecules on Microfabricated electrodes", Anal Chem, 73, pp. 1549-1559, (2001)). In most cases, embedded electrodes were carefully designed and fabricated by semiconductor processing techniques on substrates, such as silicon, glass or plastics. [0012] The field-induced assembly method is a unique application of Electrophoresis/Dielectrophoresis technology. The precise assembly of two- and three-dimensional colloidal on Conductive ITO electrode surfaces may be induced by an AC or DC electrical field that is normal to the electrode surfaces (U.S. Pat. Nos. 5,855,753, and 6,033,547). This technology was extended on silicon electrode, on which the formation, placement, and rearrangement of planar colloidal arrays can be effected by an external illumination pattern due to the photo-assisted impedance modulation. According to Seul et al, it is necessary to apply an AC electrical field to penetrate the thin oxide existing on the silicon surface (U.S. Pat. Nos. 6,251,691, 6,387,707, 6,468,811, 6,514,771, 6,706,163, and 6,797,524). A optoelectronic tweezers has also been demonstrated by Chiou et al.(Chiou, P. Y; Chang, Z; et al; Proc. IEEE/LEOS International Conference Optical MEMS, pp. 8-9, (2003)) The impedance of an amorphous silicon layer, covered by a silicon nitride layer, is modulated by a laser beam. The particles inside the electrolyte are polarized by a non-uniform AC field and pushed away from the illuminated region by the negative dielectrophoresis force. Those prior arts show superperformances on particle manipulation, but still have their limitations, such as: 1) inability to characterize particle electrically; 2) lack of advantages related to DC electric field; and 3) that the depletion layer at the semiconductor surface and the polarities switching with the AC signal make it very hard to precisely control the electric field applied on the particles. [0013] Ozkan et al have developed an optical addressing scheme to localize polymer beads on an unpatterned silicon surface based on a DC electric field (Ozkan et al, "Heterogeneous Integration through Electrokinetic Migration", IEEE Engineering in Medicine and Biology, November/December, pp 144 (2001), or Ozkan et al, "Optical Addressing of Polymer Beads in Microdevices", Sensor and Materials, Vol 14, No 4, pp 189-197, (2002)). This approach utilizes an optical microbeam that is directed on the substrate to create an active `virtual` electrode (U.S. Pat. No. 6,605,453).The localized charge is defined by the characteristics of the silicon-electrolyte interface in the electrochemical system and serves to attract oppositely charged objects within the solution. Without a layer of oxide inserted between the silicon and electrolyte, DC voltage was able to be used to manipulate the particles. This technique also has its limitations, such as: 1) undesired effects of the dark current; 2) that high-voltage biasing during the patterning process must be avoided due to the electrolysis reaction; 3) lack of advantages from the frequency response of particles on AC field; and 4) inability to characterize particle electrically. [0014] In summary, none of the previous efforts in this field disclose all of the benefits of the present invention, nor does the prior art teach or suggest all of the elements of the present invention. [0015] III. Impedance Spectroscopy [0016] Electrical impedance spectroscopy (EIS) is widely used in experimental studies to characterize living cell. For example, EIS can reflect the size, shape, and density of cells in tissue as well as the conductivity of intra and extra cellular milieu. This allows the identification of difference between tissues or between physiopatological states of the same tissue. The typical way to perform EIS on samples of tissue is the frequency sweep, with frequency range from several Hz to several MHz. [0017] Single cell analysis using DEP and micro electrical impedance spectroscopy (u-EIS) was demonstrated on bovine chromaffin cells and red blood cells (Swomitra K, et al, "A Micro System Dielectrophoresis and Electrical Impedance Spectroscopy for Cell Manipulation and Analysis", TRANSDUCERS'03, pp 1055-1058, (2003)). A micro scale electrophysiological analysis system was fabricated by micromaching technologies and cells were injected into a microreservoir. Either a vacuum or DEP was utilize to move cells in the channel and position them between platinum electrodes for impedance analysis. [0018] IV. MIS and EIS Tunnel Junction Continue reading... Full patent description for Optoelectronic probe Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Optoelectronic probe patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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