Method for aspirating sample liquid into a dispenser tip and thereafter ejecting droplets therethrough

• US 6,079,283 A
• Filed: 01/22/1998
• Issued: 06/27/2000
• Est. Priority Date: 05/31/1996
• Status: Expired due to Term

• Current Assignee: Packard Instrument Co., Inc. (Revvity, Inc.)
• Original Assignee: Packard Instruments Company
• Inventors: Papen, Roeland F., Meyer, Wilhelm, Chibucos, Nicholas S., Pelc, Richard E.
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US09/012,174
• Time in Patent Office: 887 Days
• Field of Search: 436/180, 422/100, 422/930, 73/864.01, 73/864.22, 73/864.11, 73/864.12, 73/1, 73/74, 222/36, 222/37, 222/38, 222/55, 222/57, 222/63, 222/64, 222/66, 222/148, 222/333, 901/16, 901/41, 901/43, 901/46
• US Class Current: 73/864.11
• CPC Class Codes: B01J 2219/00378 Piezoelectric or ink jet dispensers
• CPC Class Codes: B01L 3/0268 using pulse dispensing or spraying, eg. inkjet type, piezo actuated ejection of droplets from capillaries
• CPC Class Codes: C40B 60/14 for creating libraries
• CPC Class Codes: G01N 2035/00237 Handling microquantities of analyte, e.g. microvalves, capillary networks
• CPC Class Codes: G01N 2035/1039 Micropipettes, e.g. microcapillary tubes
• CPC Class Codes: G01N 2035/1041 Ink-jet like dispensers
• CPC Class Codes: G01N 35/10 Devices for transferring samples or any liquids to, in, or from, the analysis apparatus, e.g. suction devices, injection devices G01N35/0099 takes precedence
• CPC Class Codes: G01N 35/1065 Multiple transfer devices
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

A low volume liquid handling system is described which includes a microdispenser employing a piezoelectric transducer attached to a glass capillary, a positive displacement pump for priming and aspirating liquid into the microdispenser, controlling the pressure of the liquid system, and washing the microdispenser between liquid transfers, and a pressure sensor to measure the liquid system pressure and produce a corresponding electrical signal. The pressure signal is used to verify and quantify the microvolume dispensed and is used to perform automated calibration and diagnostics on the microdispenser.

Claims

1. A method for aspirating at least one sample liquid through a tip opening of a dispenser into the dispenser passage and ejecting droplets of said sample liquid from said passage through the tip opening, said method comprising:

(a) providing a system liquid into a closed container communicating with said dispenser passage;

(b) filling the dispenser passage with said system liquid;

(c) contacting the tip opening of said dispenser passage with a first sample liquid;

(d) moving said system liquid in said dispenser passage away from said tip opening so as to aspirate said first sample liquid into said passage;

(e) removing said tip opening from contact with first sample liquid;

(f) constricting the volume of said passage so as to produce and eject a droplet of said first sample liquid;

(g) allowing the volume to return to its pre-constricted volume;

(h) repeating steps (f) and (g) until a desired volume of the first sample liquid is ejected.

2. The method of claim 1 further comprising the steps of

discharging the first sample liquid remaining in said passage after step (h);

and,

discharging a sufficient volume of said system liquid through said tip opening to wash said passage.

3. The method of claim 2 further comprising the step of aspirating a second sample liquid into said passage and conducting steps (c) through (h) with respect to said second sample liquid.

4. The method of claim 1 wherein the constricting step is effected using a piezoeletric transducer.

5. The method of claim 4 wherein the filling step is effected by a positive displacement pump.

6. The method of claim 5 wherein the moving step is effected by a positive displacement pump.

7. The method of claim 6 wherein the volume of the sample liquid in step (h) is in the range from 9 nanoliters to 500 nanoliters.

8. The method of claim 1 wherein the system liquid is deionized water.

9. The method of claim 1 wherein each droplet is in the range from about 0.45 nanoliters to 5 picoliters.

10. The method of claim 9 wherein the sample liquid contains one or more biologically active substances.

11. The method of claim 1 wherein the sample liquid contains one or more chemically active substances.

12. The method of claim 1 wherein the sample liquid and the system liquid are the same.