Fluidic devices

• US 6,318,970 B1
• Filed: 03/12/1998
• Issued: 11/20/2001
• Est. Priority Date: 03/12/1998
• Status: Expired due to Fees

• Current Assignee: Micralyne, Inc. (Teledyne Technologies Incorporated)
• Original Assignee: Micralyne, Inc. (Teledyne Technologies Incorporated)
• Inventors: Backhouse, Chris J.
• Primary Examiner(s): Yuen, Henry C.
• Assistant Examiner(s): GIMIE, MAHMOUD
• Application Number:
  US09/041,865
• Time in Patent Office: 1,349 Days
• Field of Search: 417/50, 417/92, 417/65, 417/48, 417/68, 417/322, 210/222, 210/223
• US Class Current: 417/92
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: H02K 44/02 Electrodynamic pumps

Abstract

A microfluidic device operates as a pump for pumping fluid along a channel in a microchip by moving a drive fluid in the channel under the influence of a force field that is generated externally to the channel. The drive fluid is preferably a ferrofluid, and the force field is preferably a variable magnetic field. Drive fluid, driven by variation of the magnetic field, drives driven fluid through the channel. The drive fluid is recirculated, in one case by rotating the drive fluid within an enlargement in the channel, and in another case by returning the drive fluid along a return channel. A valve is formed by using a ferrofluid plug as a movable barrier for fluids in a channel. The microfluid device may be formed between two plates forming a microchip. The channels may be as small as 1 μm to 100 μm. Methods of pumping fluids by using an in channel drive fluid and exterior drive are also disclosed.

Claims

1. A micropump, comprising:

a microchip having a channel extending through the microchip, the channel having cross-sectional dimensions between 1 μ

m and 100 μ

m;

a drive fluid plug in the channel;

a driven fluid in the channel having an interface with the drive fluid plug in the channel; and

a drive for the drive fluid mounted exterior to the microchip, the drive being configured to form a changing field that in operation may drive driven fluid along the channel by changing the location of the interface between the drive fluid plug and the driven fluid.

2. The micropump of claim 1 in which the drive fluid forming the drive fluid plug is a ferrofluid formed of a suspension of magnetic particles in a carrier liquid, and the drive is a magnetic drive.

3. The micropump of claim 1 in which the drive is configured to rotate drive fluid entirely around a loop formed in the channel.

4. The micropump of claim 2 in which the drive is configured to form cogs of drive fluid disposed around the loop in the channel.

5. The micropump of claim 1 in which the channel is formed in a base plate and covered by a cover plate.

6. A micropump, comprising:

a microchip formed of a base plate and a cover plate, a channel formed in the base plate that extends through the microchip with the cover covering the channel, the channel having cross-sectional dimensions between 1 μ

m and 100 μ

m;

a drive fluid plug in the channel, the drive fluid forming the drive fluid plug being a ferrofluid formed of a suspension of magnetic particles in a carrier liquid;

a driven fluid in the channel having an interface with the drive fluid plug in the channel; and

a magnetic drive for the drive fluid mounted exterior to the microchip, the magnetic drive being configured to form a changing magnetic field that in operation may drive driven fluid along the channel by changing the location of the interface between the drive fluid plug and the driven fluid.