Microfluidic sensor complex structure

• US 8,337,683 B2
• Filed: 07/24/2008
• Issued: 12/25/2012
• Est. Priority Date: 07/26/2007
• Status: Active Grant

• Current Assignee: Precision Biosensor Inc.
• Original Assignee: i-SENS, Inc., Nano-Ditech Corporation
• Inventors: Choi, Moon Hee, Jung, Seung Hyeun, Kim, Young Hoon, Park, Joo-Heon, Nam, Hakhyun, Cha, Geun Sig
• Primary Examiner(s): Noguerola, Alex
• Assistant Examiner(s): Kaur, Gurpreet
• Application Number:
  US12/670,817
• Publication Number:
  US 20100200428A1
• Time in Patent Office: 1,615 Days
• Field of Search: 20440301-40315, 205/777.5, 205/778, 205/792, 600345-348, 435 4- 4052, 422 681- 98, 436 62- 71, 436500-548
• US Class Current: 204/403.14
• CPC Class Codes: B01L 2200/0621 Control of the sequence of chambers filled or emptied
• CPC Class Codes: B01L 2200/143 Quality control, feedback systems
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/0681 Filter
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2400/0406 capillary forces
• 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: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C

Abstract

Disclosed is a microfluidic sensor complex structure comprising a lower plate, a middle plate and an upper plate. A reference electrode, a working electrode and an electrode connection are formed on the lower plate. The middle plate comprises a microfluidic channel passage therein. The upper plate is overlaid on the middle plate so as to induce a capillary phenomenon on the microfluidic channel passage formed on in the middle plate. The microfluidic sensor complex structure allows the motion of a sample to be driven only by a capillary phenomenon, without additional operation, and allows an immune response, washing, and electrochemical analysis in one round once a sample is introduced thereinto. Hence, it requires only a short time period for measurement, is convenient to handle, and shows sensitivity and selectivity. Also, it can be produced on a mass scale because it can be formed of typical organic polymers using a simple method. Based on analytical electrochemistry, the microfluidic sensor complex structure can be used as a small-size sensor that can be applied to practice sites.

Claims

1. A microfluidic sensor complex structure, comprising:

a lower plate, on which a reference electrode, a working electrode and an electrode connection are formed;

wherein the lower plate is further provided with one or more verifying electrodes configured to minimize the deviation of detected signals, wherein the verifying electrodes are comprised of a first verifying electrode, for measuring a background signal, and a second verifying electrode for detecting a saturation signal of the saturated or partially saturated enzyme conjugate,

a middle plate, overlaid on the lower plate, comprising therein;

a sample inlet channel;

a microfluidic channel passage, which extends from the sample inlet channel and serves as a guide along which a sample flows over the entire middle plate, and which is divided at a position near the sample inlet channel into two branches, on which an enzyme conjugate reservoir and a substrate reservoir are positioned, respectively, said two branches being confluent before a detection channel, at which the reference electrode and the working electrode are exposed;

a mixing channel, positioned before a position of confluence on the microfluidic channel passage extending through the substrate reservoir, comprising an air discharge channel such that a sample flowing through the substrate reservoir reaches the detection channel later than does a sample flowing through the enzyme conjugate reservoir;

an absorbing channel in which the sample fluid flowing out of the detection channel is absorbed;

an air inlet channel provided at an end of the absorbing channel; and

an upper plate, overlaid on the middle plate so as to induce a capillary phenomenon on the microfluidic channel passage formed on in the middle plate.

2. The microfluidic sensor complex structure according to claim 1, wherein the lower plate is provided with a fluidity sensing electrode for detecting arrival of the sample at the end of the absorbing channel of the middle plate.

3. The microfluidic sensor complex structure according to claim 2, wherein the fluidity sensing electrode is configured to indicate a time point at which the substrate is allowed to advance further by detecting the arrival of the sample.

4. The microfluidic sensor complex structure according to claim 1, wherein the middle plate is further provided with a filter pad channel and a filter pad, both of which are adapted to select only an analyte component of the sample.

5. The microfluidic sensor complex structure according to claim 4, wherein the filter pad is designed to introduce only serum to the sample inlet channel.

6. The microfluidic sensor complex structure according to claim 1, wherein the sample flowing out of the enzyme conjugate reservoir reaches the working electrode a predetermined time period earlier than does the sample flowing out of the substrate reservoir.

7. The microfluidic sensor complex structure according to claim 1, wherein an antibody or a molecule-recognizing substance capable of inducing an immune response to an analyte of the sample are immobilized on the working electrode.

8. The microfluidic sensor complex structure according to claim 1, wherein the detection channel is adapted to send the electrochemical signal, generated upon an enzyme-substrate reaction between the enzyme conjugate and the substrate fluid after the immune response of the antibody or molecule-recognizing substance to the analyte, so as to yield quantitative information on the analyte.

9. The microfluidic sensor complex structure according to claim 1, wherein the absorbing channel maintains a capillary phenomenon over the microfluidic channel passage to drive movement of the sample, thereby continuing reactions in the detection channel, and serves to increase a washing effect on an unreacted material to produce highly sensitive detection signals.

10. The microfluidic sensor complex structure according to claim 1, wherein the upper plate is overlaid on the middle plate in such a manner as to expose the sample inlet channel and a terminal region of the absorbing channel, thereby inducing a capillary phenomenon on the microfluidic sensor complex structure.

11. A method for quantitatively analyzing an analyte using the microfluidic sensor complex structure of claim 1.