Droplet Actuator Devices and Methods for Immunoassays and Washing

• US 20090263834A1
• Filed: 02/26/2009
• Published: 10/22/2009
• Est. Priority Date: 04/18/2006
• 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., Srinivasan, Vijay, Pollack, Michael G.
• Granted Patent: US 8,685,754 B2
• Time in Patent Office: Days
• US Class Current: 435/7.900
• CPC Class Codes: G01N 33/54333 Modification of conditions of immunological binding reaction, e.g. use of more than one type of particle, use of chemical agents to improve binding, choice of incubation time or application of magnetic field during binding reaction

Abstract

Droplet actuator devices and methods for immunoassays and washing are provided. According to one embodiment, a method of providing a droplet in contact with a surface of a super paramagnetic bead with a reduced concentration of a substance is provided and includes: (a) providing a super paramagnetic bead in contact with a droplet comprising a starting concentration and starting quantity of the substance and having a starting volume; (b) conducting one or more droplet operations to merge a wash droplet with the droplet provided in step (a) to yield a combined droplet; and (c) conducting one or more droplet operations to divide the combined droplet to yield a set of droplets. The set of droplets includes: (i) a droplet in contact with the super paramagnetic bead having a decreased concentration of the substance relative to the starting concentration; and (ii) a droplet which is separated from the super paramagnetic bead.

Claims

1. A method of providing a droplet in contact with a surface of a super paramagnetic bead with a reduced concentration of a substance, the method comprising:

(a) providing a super paramagnetic bead in contact with a droplet comprising a starting concentration and starting quantity of the substance and having a starting volume;

(b) conducting one or more droplet operations to merge a wash droplet with the droplet provided in step (a) to yield a combined droplet; and

(c) conducting one or more droplet operations to divide the combined droplet to yield a set of droplets comprising;

(i) a droplet in contact with the super paramagnetic bead having a decreased concentration of the substance relative to the starting concentration; and

(ii) a droplet which is separated from the super paramagnetic bead.

2. The method of claim 1 wherein step 1(c) yields a droplet in contact with the surface having a decreased quantity of the substance relative to the starting quantity.

3. The method of claim 1 wherein step 1(c) yields a droplet in contact with the surface having a substantially decreased quantity of the substance relative to the starting quantity.

4. The method of claim 1 wherein step 1(c) yields a droplet in contact with the surface having a substantially decreased concentration of the substance relative to the starting concentration.

5. The method of claim 1 wherein step 1(c) yields a droplet in contact with the surface having a volume which is approximately the same as the starting volume.

6. A method of detecting insulin in a sample, the method comprising:

(a) executing droplet operations to combine affinity-based assay reagents on a droplet microactuator with a sample potentially comprising the insulin to generate a signal indicative of the presence, absence and/or quantity of insulin; and

(b) detecting the signal, wherein the signal corresponds to the presence, absence and/or quantity of the insulin in the sample.

7. The method of claim 6 wherein the sample comprises serum.

8. The method of claim 6 wherein the droplet operations are conducted in a silicone oil.

9. A method of detecting IL-6 in a sample, the method comprising:

(a) executing droplet operations to combine affinity-based assay reagents on a droplet microactuator with a sample potentially comprising the IL-6 to generate a signal indicative of the presence, absence and/or quantity of IL-6; and

(b) detecting the signal, wherein the signal corresponds to the presence, absence and/or quantity of the IL-6 in the sample.

10. The method of claim 9 wherein the sample comprises serum.

11. The method of claim 9 wherein the droplet operations are conducted in a silicone oil.