Microfabricated two-pin liquid sample dispensing system

• US 7,041,257 B2
• Filed: 12/21/2001
• Issued: 05/09/2006
• Est. Priority Date: 09/25/2001
• Status: Expired due to Term

• Current Assignee: Cytonome/St, Llc (Cytonome Inc.)
• Original Assignee: Cytonome Inc.
• Inventors: Gilbert, John, Harley, John
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): Gordon, Brian R
• Application Number:
  US10/027,171
• Publication Number:
  US 20030059345A1
• Time in Patent Office: 1,600 Days
• Field of Search: 422 99-100, 422/68.1, 738/644.2, 436/180, 141/255, 294/99.2, 606/210, 222/420, 347 6- 9, 347/19, 347/109
• US Class Current: 422/502
• CPC Class Codes: B01L 2200/143 Quality control, feedback systems
• CPC Class Codes: B01L 2200/147 Employing temperature sensors
• CPC Class Codes: B01L 2400/0439 ultrasonic vibrations, vibrating piezo elements
• CPC Class Codes: B01L 3/0244 using pins
• CPC Class Codes: B01L 3/0248 Prongs, quill pen type dispenser
• CPC Class Codes: G01N 2035/1037 Using surface tension, e.g. pins or wires
• CPC Class Codes: Y10T 436/119163 with aspirator of claimed structure
• CPC Class Codes: Y10T 436/25625 Dilution
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

A two-pin liquid sample dispensing system is provided. The two-pin dispensing system comprises a pair of separately movable pins for holding a droplet of liquid therebetween. Each pin includes a tip spaced predetermined distance from the other pin to define a sample acquisition region. The pins acquire and hold a droplet of the liquid sample in the sample acquisition region formed in the space between the tips and apply the droplet to a selected sample handing system. The distance between the tips is variable to accommodate different liquid samples having varying physical properties and to vary the volume of the acquired droplet.

Claims

1. A liquid sample dispensing system, comprising:

a holder;

a first pin coupled to the holder and having a first tip; and

a second pin coupled to the holder and having a second tip spaced a predetermined separation distance D from the first tip, wherein the first and second pins are movable relative to each other; and

at least one sensor for measuring the physical properties of a liquid sample held between the first tip and the second tip;

wherein said at least one sensor is provided on at least one of said first and second pins.

2. The liquid sample dispensing system of claim 1, further comprising a first actuator for moving the first tip to vary the initial separation distance.

3. The liquid sample dispensing system of claim 1, further comprising a second actuator for moving the second tip to vary the initial separation distance.

4. The liquid sample dispensing system of claim 1, wherein said at least one sensor also senses the separation distance between the first tip and the second tip.

5. The liquid sample dispensing system of claim 1, further comprising an actuator for varying the separation distance in response to the measurement of the physical properties.

6. The liquid sample dispensing system of claim 1, wherein the first pin and the second pin are fabricated from a silicon wafer.

7. The liquid sample dispensing system of claim 1, wherein the first tip and a second tip separated from the first tip by a variable separation distance.

8. The liquid sample dispensing system of claim 1, wherein a sample acquisition region for holding a predetermined volume of liquid sample is formed between the first pin and the second pin.

9. The liquid sample dispensing system of claim 1, further comprising a driver for effecting movement of the second pin with respect to the first pin to adjust the predetermined separation distance.

10. The liquid sample dispensing system of claim 9, wherein the second pin is attached to the holder at a fixed pivot point.

11. The liquid sample dispensing system of claim 10, wherein the driver rotates the second pin about the fixed pivot point to adjust the predetermined separation distance.

12. The liquid sample dispensing system of claim 10, wherein the driver applies one of a predetermined force and a predetermined displacement to the second pin to rotate the second pin a predetermined amount.

13. The liquid sample dispensing system of claim 9, wherein the driver comprises a silicon bar.

14. The liquid sample dispensing system of claim 13, wherein the silicon bar expands a predetermined distance to apply the predetermined force to the second pin.

15. The liquid sample dispensing system of claim 9, wherein the driver comprises a piezoelectric assembly for moving the second pin.

16. The liquid sample dispensing system of claim 9, wherein the driver comprises an electromechanical assembly for moving the second pin.

17. The liquid sample dispensing system of claim 9, wherein the driver comprises a thermoelectric assembly for moving the second pin.

18. The liquid sample dispensing system of claim 11, further comprising a bending sensor for detecting the rotation of the second pin about the fixed pivot point.

19. The liquid sample dispensing system of claim 18, wherein the bending sensor communicates with the driver to form a closed loop control circuit for controlling the amount of rotation of the second pin.

20. The liquid sample dispensing system of claim 13, wherein the silicon bar includes heating resistors for applying a controlled amount of heat to the silicon bar to effect expansion of the silicon bar.

21. The liquid sample dispensing system of claim 13, wherein the silicon bar includes at least one cooling fin for cooling the silicon bar.

22. The liquid sample dispensing system of claim 13, wherein the silicon bar includes a temperature sensor for detecting the temperature of the silicon bar.

23. The liquid sample dispensing system of claim 1, wherein one of the first tip and the second tip includes a chemical coating to enhance control over a liquid sample held in a sample acquisition region formed between the first tip and the second tip.

24. The liquid sample dispensing system of claim 23, wherein the chemical coating comprises a hydrophobic material.

25. The liquid sample dispensing system of claim 23, wherein the chemical coating comprises a hydrophilic material.

26. The liquid sample dispensing system of claim 23, wherein the chemical coating is applied in a predetermined pattern.

27. The liquid sample dispensing system of claim 26, wherein the predetermined pattern is determined by a mask used in applying the chemical coating to the tip.

28. The liquid sample dispensing system of claim 1, wherein the first tip includes a first contact surface and the movable tip includes a second contact surface defining a sample acquisition region for holding a predetermined volume of liquid sample.

29. The liquid sample dispensing system of claim 28, wherein the first contact surface and the second contact surface are tapered.

30. The liquid sample dispensing system of claim 28, wherein the first contact surface and the second contact surface are parallel.

31. The liquid sample dispensing system of claim 28, wherein one of said first contact surface and said second contact surface is curved.

32. The liquid sample dispensing system of claim 1, further comprising a relaxation region for absorbing an impact on at least one of the tips.

33. The liquid sample dispensing system of claim 32, wherein the relaxation region comprises a spring connecting the first tip and the holder.

34. The liquid sample dispensing system of claim 32, wherein the relaxation region comprises a spring connecting the second tip and the holder.

35. The liquid sample dispensing system of claim 32, wherein the relaxation region includes a sensor for measuring the force on the tips.

36. The liquid sample dispensing system of claim 1, wherein one of said first pin and said second pin includes a fulcrum region comprising a fixed pivot point to permit movement of the pin about the fixed pivot point.

37. The liquid sample dispensing system of claim 36, further comprising an actuator for moving the pin that includes the fulcrum region about the fixed pivot point.

38. The liquid sample dispensing system of claim 1, wherein one of said first pin and said second pin further includes a spring portion for absorbing an impact on the tip.

39. The liquid sample dispensing system of claim 1, wherein the holder, first pin and second pin are microfabricated from a substrate comprising a silicon wafer.

40. The liquid sample dispensing system of claim 1, wherein the holder, first pin and second pin are microfabricated from a substrate comprising a glass plate.