Method and apparatus for liquid dispensing

• US 20040072365A1
• Filed: 04/22/2003
• Published: 04/15/2004
• Est. Priority Date: 07/07/1998
• Status: Active Grant

• Current Assignee: BioDot, Inc. (ATS Corp.)
• Original Assignee: BioDot, Inc. (ATS Corp.)
• Inventors: Tisone, Thomas C., Rose, Don
• Granted Patent: US 7,736,591 B2
• Time in Patent Office: Days
• US Class Current: 436/180
• CPC Class Codes: B01J 19/0046 Sequential or parallel reactions, e.g. for the synthesis of polypeptides or polynucleotides; Apparatus and devices for combinatorial chemistry or for making molecular arrays synthesis methods per se C40B50/00
• CPC Class Codes: B01J 2219/00315 Microtiter plates
• CPC Class Codes: B01J 2219/00317 Microwell devices, i.e. having large numbers of wells
• CPC Class Codes: B01J 2219/00367 capillary
• CPC Class Codes: B01J 2219/00369 in multiple or parallel arrangements
• CPC Class Codes: B01J 2219/00378 Piezoelectric or ink jet dispensers
• CPC Class Codes: B01J 2219/00527 Sheets
• CPC Class Codes: B01J 2219/00605 the compounds being directly bound or immobilised to solid supports
• CPC Class Codes: B01J 2219/00608 DNA chips
• CPC Class Codes: B01J 2219/00612 the surface being inorganic
• CPC Class Codes: B01J 2219/00659 Two-dimensional arrays
• CPC Class Codes: B01J 2219/00722 Nucleotides
• CPC Class Codes: B01L 3/0244 using pins
• CPC Class Codes: B01L 3/0265 using valves to interrupt or meter fluid flow, e.g. using solenoids or metering valves
• CPC Class Codes: C40B 40/06 Libraries containing nucleotides or polynucleotides, or derivatives thereof
• 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 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: Y10T 436/2575 Volumetric liquid transfer

Abstract

The present invention relates to a ceramic tip and a random access print head for the transfer of microfluidic quantities of fluid. The print head can randomly collect and deposit fluid samples to transfer the samples from a source plate to a target. The print head can also be programmed to create a direct map of the fluid samples from the source plate on the target or to create any desired pattern or print on the target. The tip and print head can be used for a wide variety of applications such as DNA microarraying and compound reformatting. In one preferred embodiment, the tip is used as a capillary or “gravity” pin to draw or collect source fluid and “spot” or deposit the fluid onto the target via physical contact (touch-off). In another preferred embodiment, the tip is used in conjunction with an aspirate-dispense system to actively aspirate source fluid and deposit the fluid via a contact or non-contact approach. The tip provides improved, accurate and repeatable microfluidic transfer.

Claims

1. An apparatus for aspirating and dispensing predetermined microfluidic quantities of a fluid, comprising:

a ceramic tip including a nozzle with an inner taper to provide improved and generally laminar flow;

a drop-on-demand valve adapted to be opened and closed at a predetermined frequency and/or duty cycle to permit intermittent hydraulic coupling with said tip; and

a positive displacement pump hydraulically coupled with said valve for metering predetermined quantities of fluid to or from said tip.

2. The apparatus of claim 1, wherein at least a portion of said tip comprises a hydrophobic coating.

3. A method for using the apparatus of claim 1 to dispense a fluid from a fluid source onto a desired target substrate, comprising the following steps:

operating said pump in the reverse direction to draw a small quantity of air into said tip and thereby form an air bubble within system fluid present in said tip;

dipping said nozzle in said fluid source;

operating said pump in the reverse direction to create a reduced pressure to thereby allow a quantity of fluid from said fluid source to be aspirated into said tip; and

operating said pump in the forward direction to dispense a predetermined quantity of fluid onto said target substrate.