MICROFLUIDIC SYSTEMS AND METHODS FOR REDUCING THE EXCHANGE OF MOLECULES BETWEEN DROPLETS

• US 20130109575A1
• Filed: 12/22/2010
• Published: 05/02/2013
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Bio-Rad Laboratories Incorporated
• Original Assignee: Raindance Technologies Incorporated (Bio-Rad Laboratories Incorporated)
• Inventors: Griffiths, Andrew David, El Harrak, Abdeslam, Brouzes, Eric, Link, Darren, Kleinschmidt, Felix, Caron, Franois
• Granted Patent: US 10,837,883 B2
• Time in Patent Office: Days
• US Class Current: 506/2
• CPC Class Codes: B01L 2200/0652 Sorting or classification of particles or molecules
• CPC Class Codes: B01L 2200/0673 Handling of plugs of fluid surrounded by immiscible fluid
• 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 2400/0424 Dielectrophoretic forces
• CPC Class Codes: B01L 2400/0469 Buoyancy
• CPC Class Codes: B01L 2400/086 using baffles or other fixed flow obstructions
• 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: B01L 7/52 with provision for submitting samples to a predetermined sequence of different temperatures, e.g. for treating nucleic acid samples amplification or hybridisation processes per se C12Q1/68; controlling sequential reactions for synthesis B01J19/0046
• CPC Class Codes: C12M 25/01 Drops
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• CPC Class Codes: G01N 15/1459 the analysis being performed on a sample stream
• CPC Class Codes: G01N 15/149 specially adapted for sorting particles, e.g. by their size or optical properties
• CPC Class Codes: G01N 2015/1006 for cytology
• CPC Class Codes: G01N 2015/149 Sorting the particles
• CPC Class Codes: G01N 33/5302 Apparatus specially adapted for immunological test procedures

Abstract

The present invention generally relates to systems and methods to create stable emulsions with low rates of exchange of molecules between microdroplets.

Claims

1. A method comprising the steps of:

(a) providing within a carrier fluid a plurality of microdroplets comprising a first microdroplet comprising a first biological or chemical material and a second microdroplet comprising a second biological or chemical material, wherein the carrier fluid is immiscible with the first microdroplet and second microdroplet and comprises a first oil and a first surfactant at a first concentration within the first oil;

(b) changing the carrier fluid, in the presence of the plurality of microdroplets, by changing (i) some or all of the first oil for a second oil, (ii) some or all of the first surfactant for a second surfactant, (iii) the first concentration to a second concentration, or any combination of (i), (ii) and/or (iii).

2. The method of claim 1, further comprising the step (c) of providing a microfluidic device and wherein step (a) further comprises providing the plurality of microdroplets and the carrier fluid in the microfluidic device and/or step (b) further comprises changing the carrier fluid within the microfluidic device.

3. The method of claim 1, wherein the first biological or chemical material and/or the second biological or chemical material comprises a tissue, cell, particle, protein, antibody, amino acid, nucleotide, small molecule, pharmaceutical, and/or label.

4. The method of claim 1, wherein the first concentration is sufficient to stabilize the microdroplets against coalescing with each other in the first carrier fluid.

5. The method of claim 4, wherein the first concentration is determined, at least in part, based on stabilizing the microdroplets over a time frame determined by a reaction and/or detection of the one or more biological and/or chemical materials.

6. The method of claim 1, wherein the second concentration is sufficient to reduce exchange of the first biological or chemical material from the first microdroplet to the second microdroplet, or of the second biological or chemical material from the second microdroplet to the first microdroplet.

7. The method of claim 6, wherein the second concentration is determined, at least in part, based on stabilizing the microdroplets over a time frame determined by generation and/or use of the first microdroplet and the second microdroplet in one or more libraries.

8. The method of claim 6, wherein the changing of step (b) comprises changing the first concentration to the second concentration at least in part by providing the second oil substantially free of the first surfactant.

9. A method comprising the steps of:

(a) generating a plurality of aqueous microdroplets in a continuous phase in a microfluidic device, wherein the first continuous phase comprises a high concentration of a surfactant; and

(b) exchanging the first continuous phase containing the high concentration of surfactant for a second continuous phase containing no surfactant or a reduced concentration of surfactant.

10. The method of claim 9, wherein step (b) is accomplished in the microfluidic device.

11. The method of claim 9, wherein step (b) is accomplished, at least in part, by shifting the microdroplets from the first continuous phase into a stream of the second continuous phase.

12. The method of claim 10, wherein the shifting is accomplished by using obstacles, changing channel depth, by dielectrophoresis, or by buoyancy.