Self-locking optoelectronic tweezer and its fabrication
A novel Self-Locking Optoelectronic Tweezers (SLOT) for single microparticle manipulation across a large area is provided. DEP forces generated from ring-shape lateral phototransistors are utilized for locking single microparticles or cells in the dark state. The locked microparticles or cells can be selectively released by optically deactivating these locking sites.
1. A self-locking optical tweezers device comprising:
a first substrate comprising a plurality of ring-shaped phototransistors that can be optically turned on and off, wherein said first substrate is a doped p-type substrate where the center of the ring-shaped phototransistors and the regions outside said ring-shaped phototransistors are n-doped, and wherein said phototransistors and said first substrate are configured to produce a negative dielectrophoretic force (DEP) at the ring-shaped phototransistors on application of a voltage to said device; and that turn off the DEP at a ring-shaped phototransistor when that phototransistor is illuminated with light; and
a surface comprising a second electrode, wherein said surface is disposed to define a chamber or channel between said first substrate and said surface and said chamber or channel is configured to receive and, or to hold a fluid containing cells or particles.
2. The device of claim 1 , wherein said ring-shaped phototransistors are annular, or said ring-shaped phototransistors are bean-shaped.
3. The device of claim 1 , wherein said phototransistors create an electric field perpendicular to the plane of the apparatus.
4. The device of claim 1 , wherein said doped p-type substrate is doped p-type silicon.
5. The device of claim 1 , wherein said n-doped regions are coated with a thin film conductor.
6. The device of claim 5 , wherein said thin film conductor comprises one or more materials selected from the group consisting of Au, Ti, Al, Cr, Ni, Ta, Pd, and Pt.
7. The device of claim 1 , wherein the diameter or the major axis of said ring-shaped transistors is about 10 nm to about 20 nm.
8. The device of claim 1 , wherein:
the thickness of the ring-shaped phototransistors ranges from about 0.5 μm up to about 10 μm; or
the thickness of the ring-shaped phototransistors ranges from about 2 μm up to about 8 μm; or
the thickness of the ring-shaped phototransistors is about 5 μm.
9. The device of claim 1 , wherein said chamber or channel contains a physiological buffer.
10. The device of claim 1 , wherein a top surface of said first substrate is coated with an insulator with openings to the centers of the ring-shaped phototransistors.
11. The device of claim 10 , wherein said insulator comprises a material selected from the group consisting of SU-8 or other photoresists, PDMS, silicon dioxide, Al 2 O 3 , and silicon nitride.
12. The device of claim 11 , wherein said insulation layer is configured to provide about a 50% partial voltage leak in the dark state.
13. A self-locking optical tweezers device comprising:
a first substrate comprising a plurality of ring-shaped phototransistors that can be optically turned on and off, wherein said first substrate is a doped n-type substrate where the center of the ring-shaped phototransistors and the regions outside said ring-shaped phototransistors are p-doped, and wherein said phototransistors and said first substrate are configured to produce a negative dielectrophoretic force (DEP) at the ring-shaped phototransistors on application of a voltage to said device; and that turn off the DEP at a ring-shaped phototransistor when that phototransistor is illuminated with light; and
a surface comprising a second electrode, wherein said surface is disposed to define a chamber or channel between said first substrate and said surface and said chamber or channel is configured to receive and, or to hold a fluid containing cells or particles.
14. The device of claim 13 , wherein said ring-shaped phototransistors are annular, or said ring-shaped phototransistors are bean-shaped.
15. The device of claim 13 , wherein said p-doped regions are coated with a thin film conductor.
16. The device of claim 15 , wherein said thin film conductor comprises one or more materials selected from the group consisting of Au, Ti, Al, Cr, Ni, Ta, Pd, and Pt.
17. The device of claim 13 , wherein the diameter or the major axis of said ring-shaped transistors is about 10 μm to about 20 μm.
18. The device of claim 13 , wherein a top surface of said first substrate is coated with an insulator with openings to the centers of the ring-shaped phototransistors.
19. The device of claim 18 , wherein said insulator comprises a material selected from the group consisting of SU-8 or other photoresists, PDMS, silicon dioxide, Al 2 O 3 , and silicon nitride.
20. The device of claim 19 , wherein said insulation layer is configured to provide about a 50% partial voltage leak in the dark state.
21. A method of trapping cells or particles, said method comprising:
introducing cells or particles into a chamber of a device of claim 13 ; and
applying a voltage between said first electrode and said second electrode to trap said cells or particles at annular transistors comprising said substrate.
22. The method of claim 21 , further comprising illuminating one or more phototransistors to release trapped particles or cells.
23. A self-locking optical tweezers device comprising:
a first substrate comprising a first electrode and a plurality of ring-shaped phototransistors that can be optically turned on and off, wherein a top surface of said first substrate is coated with an insulator with openings to the centers of the ring-shaped phototransistors, and wherein said phototransistors and said first substrate are configured to produce a negative dielectrophoretic force (DEP) at the ring-shaped phototransistors on application of a voltage to said device; and that turn off the DEP at a ring-shaped phototransistor when that phototransistor is illuminated with light; and
a surface comprising a second electrode, wherein said surface is disposed to define a chamber or channel between said first substrate and said surface and said chamber or channel is configured to receive and, or to hold a fluid containing cells or particles.
24. The device of claim 23 , wherein said insulator comprises a material selected from the group consisting of SU-8 or other photoresists, PDMS, silicon dioxide, Al 2 O 3 , and silicon nitride.
25. The device of claim 23 , wherein said insulation layer is configured to provide about a 50% partial voltage leak in the dark state.
26. The device of claim 17 , wherein the diameter or the major axis of said ring-shaped transistors is about 10 μm to about 20 μm.
27. A method of trapping cells or particles, said method comprising:
introducing cells or particles into a chamber of a device of claim 23 ; and
applying a voltage between said first electrode and said second electrode to trap said cells or particles at annular transistors comprising said substrate.
28. The method of claim 27 , further comprising illuminating one or more phototransistors to release trapped particles or cells.
29. A method of trapping cells or particles, said method comprising:
introducing cells or particles into a chamber of a device of claim 1 ; and
applying a voltage between said first electrode and said second electrode to trap said cells or particles at annular transistors comprising said substrate.
30. The method of claim 29 , further comprising illuminating one or more phototransistors to release trapped particles or cells.
31. The method of claim 29 , wherein:
said voltage is an AC voltage that ranges from about 0.5 V to about 100 V pp; and
the frequency of said voltage ranges from about 1 kHz to about 50 MHz.
32. The method of claim 29 , wherein said chamber or channel contains a physiological buffer.
33. The method of claim 29 , wherein said chamber or channel contains particles or particle clusters, or cells or cell clusters.
34. The method of claim 29 , wherein:
said chamber or channel contains cells selected from the group consisting of prokaryotic cells, bacterial cells, eukaryotic cells, insect cells, mammalian cells, and avian cells.