Pipette tip handling devices and methods

1. A pipette tip dispensing device, comprising:

(a) a housing configured to engage an outside perimeter of a loading block;

(b) a distal barrier plate in connection with the housing; and

(c) an array of nested pipette tip units, each of which nested pipette tip units is aligned with a channel in the distal barrier plate; whereby a one-layer pipette tip array is in the channels;

which distal barrier plate comprises, a plurality of channels, each channels having a diameter larger than the widest portion of a pipette tip; two (2) or more different subsets of channels; a substantially flat top surface; and a substantially flat bottom surface comprising a plurality of tails around the channels; wherein:

the tails around any one subset of channels are the same length;

tails around a subset of channels have a length different than tails around another subset of channels;

the of tails around each channel are configured to contact and deflect outwards against the proximal portion of a pipette tip when a pipette tip is dispensed and passes by the tails, thereby imparting a frictional force on the pipette tip when it is dispensed; and

the plurality of tails around one subset of channels is configured to eject pipette tips through the one subset of channels at a time different than pipette tips are ejected through another subset of channels.

2. The device of claim 1 , wherein the array comprises 96, 384 or more pipette tip units.

3. The device of claim 1 , wherein each nested pipette tip unit comprises two (2) or more nested pipette tips.

4. The device of claim 1 , wherein the plurality of tails around each channel comprises four (4) or more tails.

5. The device of claim 1 , wherein the plurality of tails extend about 90 degrees from the flat bottom surface of the distal barrier plate.

6. The device of claim 5 , wherein the plurality of tails are at an internal angle of about 89° to about 80° from the bottom surface of the distal barrier plate.

7. The device of claim 1 , wherein the plurality of tails around each channel are not in the channel.

8. The device of claim 1 , wherein the housing comprises a polymer.

9. The device of claim 8 , wherein the polymer comprises molded polypropylene.

10. The device of claim 8 , wherein the polymer comprises a thickness of about 0.005 inches to about 0.05 inches.

11. The device of claim 1 , wherein the tails are about 0.01 micrometers to about 2.0 millimeters in length.

12. The device of claim 1 , comprising an actuator plate disposed above the distal barrier plate, wherein:

(i) the distal barrier plate is disposed at a top portion of the housing;

(ii) the actuator plate comprises a plurality of proximal alignment members configured to releasably engage and restrict lateral displacement of the pipette tip units; and

(iii) the proximal alignment members are disposed substantially in a plane and in an array.

13. The device of claim 12 , comprising an actuator housing that comprises a top portion, four sides, an inner surface, and a plurality of spaced detent members disposed on at least one side of the actuator housing.

14. The device of claim 13 , wherein the actuator housing comprises a polymer.

15. The device of claim 13 , wherein the inner surface of the top portion of the actuator housing comprises the actuator plate.