Apparatus and method for living cell manipulation
The present invention provides a method and system for using eye-safe infrared energy from a Class I laser to manipulate cells in culture. The laser energy produces one or more phase boundary propulsion events, which generate hydrodynamic forces sufficient to manipulate cells at the focal point.
1. A method of repositioning one or more of a plurality of cells suspended in an aqueous medium by inducing phase boundary propulsion (PBP) at a focal point in the aqueous medium, comprising providing infrared energy having a wavelength greater than 1400 nm and an energy less than 1.6 mJ per pulse from a laser through an objective lens to the aqueous medium, superheating the aqueous medium and inducing a phase transition at a temperature insufficient to produce significant ionization, moving the focal point through the medium, and repeating said step of providing the infrared energy, to produce a series of adjacent PBP bubbles.
2. The method of claim 1 , wherein said step of providing comprises providing repeated pulses at 100 to 1000 Hz.
3. The method of claim 2 , wherein said step of providing comprises providing the repeated pulses at about 100 to 200 Hz.
4. The method of claim 1 , wherein said step of providing comprises providing the infrared energy in at least two sequential pulses having different wavelengths, producing separate superheating and phase transition events.
5. The method of claim 1 , wherein said step of providing comprises providing the infrared energy in one or more pulses of duration less than 4 ms.
6. The method of claim 1 , wherein said step of providing comprises providing the infrared energy in one or more pulses of duration between 50 and 500 μs.
7. The method of claim 1 , wherein said step of providing comprises providing the infrared energy in one or more pulses of duration of about 150 μs.
8. The method of claim 1 , wherein said step of providing comprises providing the laser energy in repeated pulses having a mean power of less than 90 mW.
9. The method of claim 4 , wherein said sequential pulses are provided from separate lasers.
10. The method of claim 4 , wherein said sequential pulses comprise a first pulse having a wavelength between 1450 and 1490 nm and a second pulse having a wavelength between 1.9 and 2.1 μm, or between 1410 and 1430 nm.
11. The method of claim 10 , wherein the first pulse has a wavelength of about 1450 nm.
12. The method of claim 10 , wherein the second pulse has a wavelength of about 1.9 μm.
13. The method of claim 10 , wherein the second pulse has a wavelength of about 1420 nm.
14. The method of claim 1 , wherein said moving the focal point comprises moving a dish containing the plurality of cells suspended in the aqueous medium on a computerized microscope stage programmed to follow a specified pattern.