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.

Description

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. Optica...

AI Technical Summary

Benefits of technology

[0027] The present invention comprises a “sandwich” electrochemical cell with an inversion layer electrode defined by the area of illumination region and an instrument to characterize the particles in the electrolyte. The electrode is formed by an inversion layer maintained by a proper bias and illumination. With this novel tool, it is possible to perform biochemical analysis in an integrated semiconductor chip. In addition, the optoelectronic probe can also be a powerful tool to assemble next generation nano-electronic or optoelectronic devices. Basically, this device has the ability to trap, move, deform, merge, separate 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 on a semiconductor chip.

[0028]] The first advantage for the present invention is that the size of the electrode is self-defined by the size of light beam. It will be easy to adjust the electrode size to match a single cell by simply adjusting beam size. Therefore we are able to characterize a single cell in a convenient way. On the other hand, a large beam size can also be used to assemble a particle array. This is very different from the Optical Tweezer where the trapping zone is too small (on the order of the light wavelength) to manipulate the particle array.

[0029] The second advantage for the present invention is that an inversion region is used as a working electrode. The inversion layer has behavior similar to a metal electrode. The most of applied electric field can be shielded by the inversion layer and no significant field will penetrate into the semiconductor bulk. In addition, a majority carrier tunneling process will also reduce voltage drop on the oxide layer. Therefore a significant portion of bias will be dropped into the electrolyte. Furthermore, the metal-like electrode formed by the inversion layer is also perfect for the impedance characterization. This is very different from the conventional illumination-assisted field induced assembly technologies (or a conventional optoelectronic tweezers), where the semiconductor bulk or depletion region plays as the electrode. The involvement of the depletion region at the semiconductor surface will cause an extreme complexity on the voltage distribution among the different part of the “sandwich” electrochemical cell and make it very difficulty to analyze the impedance spectroscopy.

[0030] The third advantage for the present invention comes from a thin oxide layer formed on the silicon surface. This oxide layer will reduce the dark current significantly and a well defined electrode can be successfully formed.

[0031] The fourth advantage for the present invention comes from combination of time constant electric field and time-varying electric field. The combined use of time constant electric field and time-varying electric field can complement the limitations of EP and DEP, and potentially provide an integrated method for manipulation of bioparticles and macromolecules on microfabricated chips.

[0033] Finally, in the conventional illumination-assisted field induced assembly technologies (or a conventional optoelectronic tweezers), the illumination modulates the photoconductivity of semiconductor. The illumination in the present invention, however, is only utilized to compensate the leaking minority carrier current. Therefore, in present invention, one has extreme flexibility to choose the optical sources and can avoid the biological object integrity problem caused by focus beam with very high intensities.

Problems solved by technology

The involvement of the depletion region at the semiconductor surface will cause an extreme complexity on the voltage distribution among the different part of the “sandwich” electrochemical cell and make it very difficulty to analyze the impedance spectroscopy.

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