Apparatus and method for a highly parallel pipetter

• US 5,540,889 A
• Filed: 05/11/1994
• Issued: 07/30/1996
• Est. Priority Date: 05/11/1994
• Status: Expired due to Fees

• Current Assignee: Whitehead Institute for Biomedical Research
• Original Assignee: Whitehead Institute for Biomedical Research
• Inventors: Gordon, Steven J., Christopher, Anthony J.
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): CARRILLO, BIBI SHARIDAN
• Application Number:
  US08/240,848
• Time in Patent Office: 811 Days
• Field of Search: 422/100, 73/863.32, 73/864.14, 73/864.13
• US Class Current: 422/509
• CPC Class Codes: B01L 3/0217 of the plunger pump type medical syringes A61M
• CPC Class Codes: B01L 9/54 Supports specially adapted for pipettes and burettes automated pipetting stations G01N35/10
• CPC Class Codes: G01N 35/1065 Multiple transfer devices

Abstract

An actuator operates an upper plate assembly which holds a plurality of metal rods, such that all the rods are moved together along parallel longitudinal axes into respective tubes. The plurality of tubes is held by a lower plate assembly, a different tube for each rod. Liquid (sample fluid) is drawn into the individual tubes by the actuator raising the upper plate assembly with respect to the lower plate assembly and hence causing the rods to simultaneously traverse the length of the respective tubes from the distal ends of the tubes to the proximal ends of the tubes. The collected liquid is dispensed by the actuator lowering the upper plate assembly such that the metal rods are simultaneously lowered into the corresponding tubes. The rods are lowered very rapidly and stopped abruptly. This imparts sufficient velocity to the collected sample fluid within the tubes such that the samples under inertia separate from and cleanly exit the distal ends of the tubes. As such, low volume (microvolume) dispenses are enabled in a manner free of sample contact with the target (receiving) tray.

Claims

1. A pipetter system for pipetting in parallel through a plurality of pipettes comprising:

an actuator for operation along a longitudinal axis;

an upper plate assembly holding a plurality of rods, the upper plate assembly coupled to the actuator for movement by the actuator through a series of planes that are perpendicular to the longitudinal axis, such that the upper plate assembly lies in a plane perpendicular to the longitudinal axis, each rod having a working end spaced from and facing away from the upper plate assembly; and

a lower plate assembly (i) lying in a plane spaced apart from and parallel to the plane of the upper plate assembly, and (ii) holding a plurality of tubes for receiving the rods, working end first, of the upper plate assembly, there being a different rod for each tube and each rod being axially aligned with its respective tube, each tube having a proximal end through which the respective rod is received and a distal end opposite the proximal end,

upon the actuator moving the upper plate assembly with respect to the lower plate assembly the rods simultaneously traverse the length of the respective tubes, the rods traversing the length of the respective tubes from the distal ends to the proximal ends of the tubes collecting sample fluid in each tube, and the rods traversing the length of the respective tubes from the proximal end to the distal end dispensing collected sample fluid, the working end of each rod being in direct contact with the collected sample fluid of the respective tube, wherein the actuator moves the upper plate assembly in a manner such that when the rods traverse the length of the respective tubes from the proximal ends to the distal ends of the tubes sufficient velocity is imparted to the collected sample fluid to enable collected sample fluid to cleanly exit the distal ends of the tubes and wherein the actuator abruptly stops movement of the upper plate assembly such that the rods are abruptly stopped at the distal ends of the respective tubes and the collected sample fluid under inertia exits the respective tubes and wherein each rod has an outer diameter on the order of 1000th of an inch smaller than the inner diameter of the respective tube such that when the rods traverse the length of the respective tubes, each rod has a sufficiently small gap between the rod along its length and inner walls of the respective tube that, with the fluid, forms a seal and maintains the working end of the rod in contact with the sample fluid, enabling each tube to be free of mechanical seals.

2. A pipetter system as claimed in claim 1 wherein for each tube, the lower plate assembly has a chamfered opening for holding the tube such that sample fluid is funneled into the proximal end of the tube.

3. A pipetter system as claimed in claim 1 wherein the actuator is of pneumatic, manual or motorized operation.

4. A pipetter system as claimed in claim 1 further comprising:

a spring mechanism for enabling the actuator to move the upper plate assembly such that the rods traverse the length of the respective tubes from the distal ends to the proximal ends of the tubes for collecting sample fluid in each tube; and

an adjustable stop positioned adjacent the actuator for stopping upward movement of the upper plate assembly and hence stopping movement of the rods along the length of the respective tubes from the distal ends to the proximal ends of the respective tubes, such that a certain amount of sample fluid is collected in each tube, the position of the stop (i) determining amount of sample fluid able to be collected in each tube and (ii) being predetermined by a user such that a desired amount of sample fluid is collected in each tube.

5. A pipetter system as claimed in claim 4 wherein the adjustable stop includes a screw formed of a shaft and a head, the screw shaft having markings for indicating certain increments of sample fluid which will be collected when the screw is turned to that marking, and the screw head providing indications of fractions of the shaft increments such that position of the screw provides an indication of the amount of sample fluid to be obtained with the screw at that position.

6. A pipetter system as claimed in claim 1 wherein the lower plate assembly further includes alignment pins extending therefrom, and

the pipetter system further comprises a holder having (i) a vertical recessed area for holding a subject tray, the tray having a plurality of predefined work areas, and (ii) a plurality of holes outside the vertical recessed area for receiving the alignment pins of the lower plate assembly to align the distal ends of the tubes and respective rods with the work areas of the subject tray.

7. A pipetter system as claimed in claim 6 wherein a subset of the holes of the holder receive the alignment pins of the lower plate assembly for aligning the distal ends of the tubes and respective rods with a subset of the work areas of the subject tray, and a different subset of the holes of the holder receive the alignment pins of the lower plate assembly for aligning the distal ends of the tubes and respective rods with a different subset of the work areas of the subject tray.

8. A pipetter system has claimed in claim 6 further comprising vertical elevation means in the vertical recessed area of the holder, the elevation means for positioning the working areas of the subject tray closer to the distal ends of the tubes and respective rods.

9. A pipetter system as claimed in claim 1 wherein the upper plate assembly further includes brackets for removably coupling the upper plate assembly to the actuator.

10. A pipetter system as claimed in claim 1 further comprising a housing for enclosing the actuator, upper plate assembly and lower plate assembly, the housing providing a handle for hand held use of the pipetter system.