Apparatus for acoustic ejection of circumscribed volumes from a fluid

1. An apparatus for separating, from a carrier fluid containing a plurality of circumscribed volumes each having a different acoustic impedance than the carrier fluid, one or more of the circumscribed volumes, the apparatus comprising:

(a) a container housing the fluid and having a fluidic channel with an upper opening, said fluidic channel having dimensions permitting the carrier fluid containing said plurality of circumscribed volumes to flow freely through said channel;

(b) a substrate above said opening having a surface substantially parallel to a plane that contains the opening; and

(c) an acoustic ejector for acoustically ejecting from said carrier fluid onto a location on the substrate surface a circumscribed volume having a different acoustic impedance than said carrier fluid.

2. The apparatus of claim 1 , further comprising a mechanism for positioning the acoustic ejector relative to the fluid in the container.

3. The apparatus of claim 1 , wherein each of the plurality of circumscribed volumes comprises a cell.

4. The apparatus of claim 3 , wherein the width of the channel is just wider than a cell contained in one of the plurality of circumscribed volumes.

5. The apparatus of claim 1 , further comprising cooling means for lowering the temperature of the substrate surface.

6. The apparatus of claim 1 , further comprising a fluid column fluidically connected to the fluid channel.

7. The apparatus of claim 1 , further comprising a device which positions the substrate relative to the fluid channel.

8. The apparatus of claim 1 , wherein the substrate is porous.

9. The apparatus of claim 1 , further comprising a device for driving cells closer to a surface of the fluid within the fluidic channel.

10. The apparatus of claim 9 , wherein the device for driving cells operates by generating a photon field.

11. The apparatus of claim 9 , wherein the device for driving cells operates by generating focused acoustic energy.