Capacitance detection in a droplet actuator

• US 9,321,049 B2
• Filed: 07/23/2014
• Issued: 04/26/2016
• Est. Priority Date: 02/15/2007
• Status: Active Grant

• Current Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Original Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Inventors: Sturmer, Ryan A., Pollack, Michael G., Pamula, Vamsee K., Srinivasan, Vijay, Paik, Philip Y.
• Primary Examiner(s): Baldridge, Benjamin M
• Assistant Examiner(s): HOQUE, FARHANA AKHTER
• Application Number:
  US14/338,889
• Publication Number:
  US 20140332380A1
• Time in Patent Office: 643 Days
• Field of Search: 324658-690, 436/150
• US Class Current: 1/1
• CPC Class Codes: B01L 2200/0605 Metering of fluids
• CPC Class Codes: B01L 2300/0627 Sensor or part of a sensor is integrated
• CPC Class Codes: B01L 2300/0636 Integrated biosensor, microarrays
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/0809 rectangular shaped
• CPC Class Codes: B01L 2400/0427 Electrowetting
• 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 3/502784 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 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension
• CPC Class Codes: G01N 2203/00 Investigating strength properties of solid materials by application of mechanical stress
• CPC Class Codes: G01N 27/22 by investigating capacitance
• CPC Class Codes: G01N 27/223 for determining moisture content, e.g. humidity rain detectors on vehicle windows B60S1/0825
• CPC Class Codes: G01N 27/227 Sensors changing capacitance upon adsorption or absorption of fluid components, e.g. electrolyte-insulator-semiconductor sensors, MOS capacitors G01N27/225 takes precedence
• CPC Class Codes: G01V 3/02 operating with propagation of electric current

Abstract

A method, circuit and apparatus for detecting capacitance on a droplet actuator, inter alia, for determining the presence, partial presence or absence of a droplet at an electrode on a droplet actuator by: (a) providing a droplet actuator comprising: (i) a substrate comprising electrodes arranged on the substrate for conducting droplet operations on a surface of the substrate; (ii) a capacitance detection circuit for detecting capacitance at the droplet operations surface at one or more of the electrodes; (b) detecting capacitance at the droplet operations surface at one or more of the electrodes; and (c) determining from the capacitance the presence, partial presence or absence of a droplet at the droplet operations surface at the electrode.

Claims

1. A method of determining whether a droplet comprises one or more beads, the method comprising:

(a) providing a droplet on an electrode on a droplet actuator;

(b) determining capacitance at the electrode;

(c) comparing the capacitance with an expected capacitance in the presence of one or more beads;

(d) determining whether one or more beads is present; and

wherein the determination;

(i) follows a droplet splitting operation in a bead washing protocol; and

(ii) identifies whether bead loss has occurred during the splitting operation.

2. The method of claim 1 wherein the step of providing a droplet on an electrode on a droplet actuator is mediated by a means comprising electrowetting.

3. The method of claim 1 wherein the step of providing a droplet on an electrode on a droplet actuator is not mediated by a means comprising dielectrophoresis.