Droplet actuator devices and methods employing magnetic beads

• US 10,379,112 B2
• Filed: 05/22/2015
• Issued: 08/13/2019
• Est. Priority Date: 02/09/2007
• Status: Active Grant

• Current Assignee: Duke University, Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Original Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Inventors: Sista, Ramakrishna, Pamula, Vamsee K., Pollack, Michael G., Srinivasan, Vijay, Eckhardt, Allen E., Fair, Richard B.
• Primary Examiner(s): Fritchman, Rebecca M
• Application Number:
  US14/719,731
• Publication Number:
  US 20150314293A1
• Time in Patent Office: 1,544 Days
• Field of Search: 435 79, 436 2, 422 67, 422 63, 422400
• CPC Class Codes: B01L 2200/025 Align devices or objects to ensure defined positions relative to each other
• CPC Class Codes: B01L 2200/028 Modular arrangements
• CPC Class Codes: B01L 2200/0647 Handling flowable solids, e.g. microscopic beads, cells, particles
• CPC Class Codes: B01L 2200/0673 Handling of plugs of fluid surrounded by immiscible fluid
• CPC Class Codes: B01L 2200/141 Preventing contamination, tampering
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2400/0427 Electrowetting
• CPC Class Codes: B01L 2400/043 magnetic forces
• CPC Class Codes: B01L 3/502715 characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
• CPC Class Codes: B01L 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: B01L 3/502761 specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules investigating characteristics of particles G01N15/00
• CPC Class Codes: B01L 3/502784 specially adapted for droplet or plug flow, e.g. digital microfluidics automatic analysis using a stream of discrete samples in a tube system G01N35/08
• CPC Class Codes: C12M 25/01 Drops
• CPC Class Codes: C12M 25/16 Particles; Beads; Granular material; Encapsulation chemical or physical processes conducted in the presence of fluids and solid particles B01J8/00
• CPC Class Codes: G01N 2035/1046 Levitated, suspended drops
• CPC Class Codes: G01N 27/44717 Arrangements for investigating the separated zones, e.g. localising zones
• CPC Class Codes: G01N 27/44786 of the magneto-electrophoresis type
• CPC Class Codes: G01N 33/54326 Magnetic particles
• CPC Class Codes: G01N 33/54386 : Analytical elements
• CPC Class Codes: G01N 35/0098 : involving analyte bound to insoluble magnetic carrier, e.g. using magnetic separation magnetic particles used in immunoassays G01N33/54326; magnetic separation in general B03C

Abstract

A method of providing a droplet in contact with a magnetically responsive bead and having a reduced quantity of a substance. The method generally includes the steps of (a) providing a droplet actuator comprising: (i) a substrate comprising electrodes arranged for conducting droplet operations on a surface; (ii) a starting droplet comprising: (1) one or more magnetically responsive beads; (2) a starting quantity of the substance; and (3) a starting volume; (b) magnetically immobilizing the one or more magnetically responsive beads at a location which is at a distance from a target droplet splitting zone; (c) conducting one or more droplet operations comprising droplet dividing operations selected to divide the combined droplet to yield a set of droplets comprising: (i) a droplet comprising substantially all of the one or more magnetically responsive beads and having a decreased quantity of the substance relative to the starting concentration; and (ii) a droplet substantially lacking the magnetically responsive beads.

Claims

1. A modular droplet actuator assembly, comprising:

a. a first module comprising a droplet actuator comprising a first droplet actuator substrate, the first droplet actuator substrate having an arrangement of electrodes thereon and the arrangement of electrodes configured to conduct one or more droplet operations;

b. a second module comprising one or more magnets and a magnet assembly comprising a first magnet assembly substrate that is not a top plate of the droplet actuator, wherein the first magnet assembly substrate has one or more magnets mounted thereon to form a populated magnet assembly; and

c. a third module comprising a mount configured for mounting the magnet assembly and droplet actuator thereto, the mount having first and second recessed trays to receive the magnet assembly and droplet actuator, wherein the first recessed tray is positioned below the second recessed tray, such that when the populated magnet assembly and the droplet actuator are mounted in the mount, the one or more magnets of the populated magnet assembly are aligned with one or more predetermined positions on the arrangement of electrodes to magnetically effect droplet operations utilizing magnetically responsive beads at the predetermined positions.

2. The modular droplet actuator assembly of claim 1 wherein magnet assembly and droplet actuator are mounted to the mount such that the magnet assembly is substantially aligned with certain electrodes of the arrangement of electrodes of the droplet actuator.

3. The modular droplet actuator assembly of claim 1 wherein the electrodes comprise electrowetting electrodes.

4. The modular droplet actuator assembly of claim 1 wherein the droplet actuator further comprises a second droplet actuator substrate spaced apart from the first droplet actuator substrate to form a gap therebetween.

5. The modular droplet actuator assembly of claim 1 wherein the one or more magnets are at least one of permanently and removably mounted to the first magnet assembly substrate.

6. The modular droplet actuator assembly of claim 5 wherein the one or more magnets are grouped in one or more sets of magnets based on certain magnetic properties.

7. The modular droplet actuator assembly of claim 6 wherein the magnetic properties comprise one or more of magnetic field orientation and magnetic strength.

8. The modular droplet actuator assembly of claim 6 wherein a user selects a set of the one or more sets of magnets based on desired magnet properties.

9. The modular droplet actuator assembly of claim 5 wherein the one or more magnets are shaped such that they can be mounted to the magnet assembly only in a predefined orientation.

10. The modular droplet actuator assembly of claim 5 wherein the one or more magnets are mounted to the magnet assembly in one of a row and grid arrangement.

11. The modular droplet actuator assembly of claim 5 wherein the one or more magnets and/or magnet assemblies are marked or coded based on their magnetic properties.

12. The modular droplet actuator assembly of claim 1 wherein the magnet assembly and droplet actuator are mounted into the mount via one or more fittings.

13. The modular droplet actuator assembly of claim 12 wherein the one or more fittings comprise one or more slots and/or openings.

14. The modular droplet actuator assembly of claim 12 wherein the one or more fittings comprise one or more of posts, screws, threaded posts, nuts, spring loaded mechanisms, and complimentary fittings.

15. The modular droplet actuator assembly of claim 12 wherein the one or more fittings are configured such that the magnet assembly and/or droplet actuator can be mounted in multiple positions onto the mount.

16. The modular droplet actuator assembly of claim 12 wherein the one or more fittings are configured such that multiple magnet assemblies and/or multiple droplet actuators can be mounted onto the mount.

17. The modular droplet actuator assembly of claim 12 wherein the one or more fittings are configured such that the magnet assembly can be mounted one or more of above, below, and/or beside the droplet actuator.

18. The modular droplet actuator assembly of claim 1 wherein at least one of the one or more magnets is a neodymium permanent magnet.