Pipetter

• US 6,374,683 B1
• Filed: 01/29/2000
• Issued: 04/23/2002
• Est. Priority Date: 01/29/1999
• Status: Expired due to Fees

• Current Assignee: Digilab, Inc.
• Original Assignee: Genomic Instrumentation Services, Inc. (Digilab, Inc.)
• Inventors: Hunicke-Smith, Scott P., Medeiros, Omar
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US09/493,429
• Time in Patent Office: 815 Days
• Field of Search: 738/641.7, 738/633.2
• US Class Current: 73/864.17
• CPC Class Codes: B01J 2219/00691 using robots
• CPC Class Codes: B01L 2400/0409 centrifugal forces
• CPC Class Codes: B01L 3/0217 of the plunger pump type medical syringes A61M
• CPC Class Codes: B01L 3/5085 for multiple samples, e.g. microtitration plates
• CPC Class Codes: B04B 2011/046 Loading, unloading, manipulating sample containers
• CPC Class Codes: B04B 5/0407 for liquids contained in receptacles B04B5/0442 takes precedence
• CPC Class Codes: B04B 5/10 Centrifuges combined with other apparatus, e.g. electrostatic separators; Sets or systems of several centrifuges B04B5/12 takes precedence; magnetic or electrostatic separators B03C; amassing particles by electric fields, e.g. by agglomeration B03C3/0175
• CPC Class Codes: B04B 9/00 Drives specially designed for centrifuges; Arrangement or disposition of transmission gearing; Suspending or balancing rotary bowls
• CPC Class Codes: G01N 2035/00495 Centrifuges
• CPC Class Codes: G01N 2035/1069 by adjusting the spacing between multiple probes of a single transferring head
• CPC Class Codes: G01N 35/0099 comprising robots or similar manipulators robots per se B25J
• CPC Class Codes: G01N 35/028 having reaction cells in the form of microtitration plates
• CPC Class Codes: G01N 35/1065 Multiple transfer devices
• CPC Class Codes: G01N 35/1067 for transfer to or from containers having different spacing
• CPC Class Codes: G01N 35/1074 arranged in a two-dimensional array

Abstract

A micropipetter a plurality of hollow needles to deliver fluid, the needles being anchored in a sample block; a needle guide assembly with a plurality of needle guide shafts and compression springs attached at one end to the sample block and at the other end to a needle guide plate, each spring surrounding a needle guide shaft, and the needle guide plate controlling the spacing of the needles; a sample block having a plurality of hollow, tapered spaces, each of which connect with the hollow needle; a displacement volume block having a plurality of hollow spaces, each being occupied by a piston pin, each piston pin being sealed with a stationary seal assembly; a stationary sheet seal located between the sample block and the displacement volume block, the sheet seal having a plurality of holes corresponding to and separating the spaces in the sample block and the displacement volume block, such that precise volume displacement is provided; a seal constraint plate located above the displacement volume block, the seal constraint plate positioned to hold in place an airtight, low-friction seal assembly around each of the piston pins; the piston pins being attached to a piston pin plate; and a motive means for moving the pistons vertically and thereby alternately aspirating fluid into the needles and dispensing fluid from the needles. The seal assembly has at least one sleeve and one O-ring. The motive means is at least one motor having at least one lead-screw drive which goes through the core of the motor, the lead-screw drive being attached to an armature, such that actuating the motor causes the lead-screw drive to pull up or lower the rest of the micropipetter. Optionally, the micropipetter has at least one set of crossbars, each crossbar being attached to the constraint plate and the piston pin plate to increase stability and precise movement. The micropipetter needles can number 1, 8, 16,24, 96, 384 or 1536. Optionally, the micropipetter has a counter-balance to aid in hand-held use.

Claims

1. A micropipetter comprising

a. a plurality of hollow needles to deliver fluid, said needles being anchored in a sample block;

b. a needle guide assembly comprising a plurality of needle guide shafts and compression springs, each attached at one end to the sample block and at the other end to a needle guide plate, each spring surrounding a needle guide shaft, and the needle guide plate guiding the spacing of the needles;

c. a sample block having a plurality of hollow spaces, each of which connect with the hollow needle;

d. a displacement volume block having a plurality of hollow spaces, each being occupied by a piston pin, each piston pin being sealed with a stationary seal assembly;

e. a stationary sheet seal located between the sample block and the displacement volume block, the sheet seal having a plurality of holes corresponding to and separating the spaces in the sample block and the displacement volume block, such that precise volume displacement is provided;

f. a seal constraint plate located above the displacement volume block, the seal constraint plate being positioned to hold in place an airtight, low-friction seal assembly around each of the piston pins;

g. the piston pins being attached to a piston pin plate; and

h. motive means for moving the pistons vertically and thereby alternately aspirating fluid into the needles and dispensing fluid from the needles.

2. The micropipetter of claim 1, wherein the seal assembly comprises an upper sleeve which is in contact with the piston pin, an upper O-ring which is positioned between the upper sleeve and a compression-adjust spacer, a lower sleeve and a lower O-ring which is positioned between the lower sleeve and the compression-adjust spacer.

3. The micropipetter of claim 2, wherein the upper and lower sleeves are Teflon.

4. The micropipetter of claim 1, wherein the seal assembly comprises upper and lower sleeves and two intervening O-rings.

5. The micropipetter of claim 1, wherein the seal assembly comprises one sleeve and one O-ring.

6. The micropipetter of claim 1, wherein the motive means comprises at least one motor having at least one lead-screw drive which goes through the core of the motor, the lead-screw drive being attached to an armature, such that actuating the motor causes the lead-screw drive to pull up or lower the rest of the micropipetter.

7. The micropipetter of claim 1, further comprising at least one set of crossbars, each crossbar being attached to the constraint plate and the piston pin plate, thereby increasing stability of the micropipetter and aiding in precise movement.

8. The micropipetter of claim 1, wherein the plurality of hollow needles numbers 1, 8, 16, 24, 96, 384, or 1536.

9. The micropipetter of claim 1, further comprising a counter-balance to aid in hand-held use.

10. The micropipetter of claim 1, incorporated into a robotic workstation.

11. The micropipetter of claim 1, wherein the motive means is controlled by an on-board microprocessor.