Optoelectronic tweezers for microparticle and cell manipulation

Abstract

An optical image-driven light induced dielectrophoresis (DEP) apparatus and method are described which provide for the manipulation of particles or cells with a diameter on the order of 100 μm or less. The apparatus is referred to as optoelectric tweezers (OET) and provides a number of advantages over conventional optical tweezers, in particular the ability to perform operations in parallel and over a large area without damage to living cells. The OET device generally comprises a planar liquid-filled structure having one or more portions which are photoconductive to convert incoming light to a change in the electric field pattern. The light patterns are dynamically generated to provide a number of manipulation structures that can manipulate single particles and cells or group of particles/cells. The OET preferably includes a microscopic imaging means to provide feedback for the optical manipulation, such as detecting position and characteristics wherein the light patterns are modulated accordingly.

What is claimed is: 
     
       1. An apparatus for manipulating cells or particles by light induced dielectrophoresis (DEP), the apparatus comprising:
 a first surface and a second surface configured for retaining a liquid comprising particles or cells to be manipulated; 
 at least one photoconductive area on said first or said second surface configured for conversion of received light to a local electric field in the vicinity of the received light; 
 a light source to provide the light received by the photoconductive area; 
 wherein the local electric field selectively repels or attracts particles or cells; 
 a microvision-based pattern recognition subsystem which is configured for controlling the output of said light source in response to registering the position of, and optionally the characteristics of, particles or cells as determined from microscopic imaging. 
 
     
     
       2. An apparatus as recited in  claim 1 , wherein said characteristics are selected from the group of particle and cell characteristics consisting essentially of size, color, shape, texture, viability, motility, conductivity, permeability, capacitance and response to changes in the environment of the particle or cell. 
     
     
       3. An apparatus for manipulating cells and particles using optical image-driven light induced dielectrophoresis (DEP) over a two-dimensional area, comprising:
 a first surface and second surface configured for retaining a liquid containing particles, or cells to be manipulated; 
 at least one photoconductive area on said first or second surface which is configured for inducing a local electric field, virtual electrode, in the vicinity of received light; 
 an optical projector or scanning laser configured for generating dynamic sequential two-dimensional light patterns onto said photosensitive surface thereby inducing dynamic localized electric fields for DEP manipulation of particles or cells; and 
 a microscopic imaging subsystem which is configured for controlling the output of said optical projector in response to registering the position of, and optionally the characteristics of, particles or cells as determined from analyzing microscopic images. 
 
     
     
       4. An apparatus as recited in  claim 3 , wherein said characteristics are selected from the group of particle and cell characteristics consisting essentially of size, color, shape, texture, viability, motility, conductivity, permeability, capacitance and response to changes in the environment of the particle or cell. 
     
     
       5. An apparatus as recited in claim 1, wherein said microvision-based pattern recognition subsystem is further configured for controlling said light source to project a pattern of light onto said photoconductive area that traps ones of said particles or cells. 
     
     
       6. An apparatus as recited in claim 5, wherein said pattern of light comprises traps each of which traps an individual one of said particles or cells. 
     
     
       7. An apparatus as recited in claim 6, wherein each of ones of said traps comprises an enclosure light pattern enclosing an individual one of said particles or cells, said enclosure light pattern creating an electric field cage that repels by dielectrophoresis said particle or cell, thereby trapping said particle or cell. 
     
     
       8. An apparatus as recited in claim 7, wherein said enclosure light pattern is a ring. 
     
     
       9. An apparatus as recited in claim 6, wherein said microvision-based pattern recognition subsystem is further configured for controlling said light source to change said pattern of light projected onto said photoconductive area to move ones of said traps, thereby moving ones of said particles or cells. 
     
     
       10. An apparatus as recited in claim 3, wherein said microscopic imaging subsystem is further configured for controlling said optical projector or scanning laser to generate a pattern of light onto said photoconductive area that traps ones of said particles or cells. 
     
     
       11. An apparatus as recited in claim 10, wherein said pattern of light comprises traps each of which traps an individual one of said particles or cells. 
     
     
       12. An apparatus as recited in claim 11, wherein each of ones of said traps comprises an enclosure light pattern enclosing an individual one of said particles or cells, said enclosure light pattern creating an electric field cage that repels by dielectrophoresis said particle or cell, thereby trapping said particle or cell. 
     
     
       13. An apparatus as recited in claim 12, wherein said enclosure light pattern is a ring. 
     
     
       14. An apparatus as recited in claim 11, wherein said microscopic imaging system is further configured for controlling said optical projector or scanning laser to change said pattern of light generated onto said photoconductive area to move ones of said traps, thereby moving ones of said particles or cells.