Membrane strip biosensor system for point-of-care testing

• US 20040214253A1
• Filed: 04/20/2004
• Published: 10/28/2004
• Est. Priority Date: 04/25/2003
• Status: Active Grant

• Current Assignee: Biodigit Laboratories Corporation
• Original Assignee: Biodigit Laboratories Corporation
• Inventors: Cho, Jung Hwan, Paek, Se Hwan, Kim, Ser Ka
• Granted Patent: US 7,300,802 B2
• Time in Patent Office: Days
• US Class Current: 435/7.92
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: G01N 33/54388 based on lateral flow
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: Y10S 436/808 Automated or kit
• CPC Class Codes: Y10S 436/81 Tube, bottle, or dipstick
• CPC Class Codes: Y10S 436/823 Immunogenic carrier or carrier per se

Abstract

The present invention relates to a biosensor for point-of-care testing (POCT) whose detection sensitivity was remarkably improved by introducing to membrane strip chromatographic assay system a successive cross-flow procedure for immune reaction and enzymatic reaction. The present invention relates to a membrane strip biosensor system that comprises

(a) a membrane pad (10) for sample application,

(b) a membrane pad (20) for release of detection binding component, wherein the membrane pad (20) contains label-linked binding component for detection in a dry state,

(c) a signal generation membrane pad (30) with immobilized binding component for capture,

(d) a membrane pad (40) for absorption of vertical flow medium,

(e) a membrane pad (50) for the supply of substrate solution for enzyme,

(f) a membrane pad (60) for absorption of horizontal flow medium and

(g) substrate solution,

wherein the system has a cross-arrangement of two groups of the membrane pads,

(I) one group of vertically arranged pads, wherein the pad (10) is partially superimposed and fixed in length at the end of the pad (20), and the pad (20) and the pad (40) are partially superimposed and fixed in length at the both ends of the signal generating membrane pad (30), respectively; and

(II) the other group of horizontally arranged pads, wherein the pad (50) and pad (60) are, at the time of signal generation, partially superimposed and fixed at the both lateral sides of the signal generation membrane pad (30), respectively.

Claims

1. A membrane strip biosensor system characterized to comprise

(a) a membrane pad (10) for sample application,

(b) a membrane pad (20) for release of detection binding component, wherein the membrane pad (20) contains label-linked binding component for detection in a dry state,

(c) a signal generation membrane pad (30) with immobilized binding component for capture,

(d) a membrane pad (40) for absorption of vertical flow medium,

(e) a membrane pad (50) for the supply of substrate solution for enzyme,

(f) a membrane pad (60) for absorption of horizontal flow medium and

(g) substrate solution,

wherein the system has a cross-arrangement of two groups of the membrane pads,

(I) one group of vertically arranged pads, wherein the pad (10) is partially superimposed and fixed in length at the end of the pad (20), and the pad (20) and the pad (40) are partially superimposed and fixed in length at the both ends of the signal generating membrane pad (30), respectively;

and

(II) the other group of horizontally arranged pads, wherein the pad (50) and pad (60) are, at the time of signal generation, partially superimposed and fixed at the both lateral sides of the signal generation membrane pad (30), respectively.

2. The membrane strip biosensor system in claim 1, wherein the horizontal arrangement pads (50) and (60) are either

(i) fixed at the both lateral sides of the signal generation membrane pad (30) belong to the vertical arrangement pads, or

(ii) remained in a separated state at first and then fixed to the signal generation pad after the completion of the vertical flow reaction.

3. The membrane strip biosensor system in claim 1, wherein the vertical arrangement pads are prepared separately from the horizontal arrangement pads, and the two groups fixed on separate plates are combined in a cross-position by transferring any one plate over the other to be a cruciform.

4. The membrane strip biosensor system in claim 1, wherein for an electrochemical determination, an electrode is either directly established on the signal generation membrane pad (30) or separately fabricated and combined with the pad at the time of signal detection.

5. The membrane strip biosensor system in claim 1, wherein the substrate solution is prepared either in a container placed at a predetermined site above the membrane pad (50) for facilitating its supply at the time of enzyme reaction or in a separate container from the analytical system.

6. The membrane strip biosensor system in claim 1, wherein the membrane pad (10) for sample application, the membrane pad (20) for release of detection binding component, and the membrane pad (50) for the supply of substrate solution are a glass fiber membrane, the signal generation membrane pad (30) is a nitrocellulose membrane, and the embrane pads (40) and (60) for absorption are a cellulose membrane.

7. The membrane strip biosensor system in claim 1, wherein the label-linked binding component for detection comprises either

i) the conjugate of a label with a binding component for detection, or

ii) a binding component for detection and the conjugate of a label with a secondary binding component specific to the binding component for detection.

8. The membrane strip biosensor system in claim 7, wherein the binding component for detection is antibody, enzyme, receptor, or DNA that reacts specifically with an analyte.

9. The membrane strip biosensor system in claim 7, wherein the tracer is horseradish peroxidase, alkaline phosphatase, β

-galactosidase, or arthromyces ramosus peroxidase and the substrate solution comprises a chromogenic substrate component specific to an enzyme, and, at the time of signal generation, color change detectable with naked eyes is shown as signal by enzyme-substrate reaction.

10. The membrane strip biosensor system in claim 7, wherein the tracer is gold colloids and the substrate solution comprises a silver compound, and, at the time of signal generation, color change detectable with naked eyes is shown as signal by chemical catalytic reaction.

11. The membrane strip biosensor system in claim 7, wherein the tracer is horseradish peroxidase or arthromyces ramosus peroxidase and the substrate solution comprises luminol or other luminescent substrate components specific to an enzyme, and at the time of signal generation, a light signal is measured as signal by enzyme-substrate reaction.

12. The membrane strip biosensor system in claim 7, wherein the tracer is Co²⁺, Cu²⁺, Mg²⁺, Fe²⁺ or their compounds and the substrate solution comprises luminol or other luminescent substrate component, and at the time of signal generation, a light signal is measured as signal by chemical catalytic reaction.

13. The membrane strip biosensor system in claim 7, wherein the tracer is glucose oxidase, urease, penicillin oxidase, or cholesterol oxidase and the substrate solution comprises an electrochemical signal-generating component specific to an enzyme, and, at the time of signal generation, conductivity change, current change, or voltage change is measured as signal by enzyme-substrate reaction.

14. The membrane strip biosensor system in claim 1, wherein the binding component for capture is antibody, enzyme, receptor, or DNA which reacts specifically with an analyte or with a counter part present on the complex formed between the binding component and an analyte.

15. The membrane strip biosensor system in claim 1, wherein the system is constructed in such an arrangement that the vertical arrangement pads (10), (20), (30) and (40) are fixed inside the bottom part (72) of the holder of the system which has a signal detection window (78) and a substrate solution container-perforating needle (75), the horizontal arrangement pads (50) and (60) are fixed on the horizontal arrangement pad-fixing frame (74) existing inside the top part (71) of the holder with a sample addition hole, wherein the frame (74) is connected with the flow transfer button (73) present outside the top part (71), and the substrate solution container (76) containing the substrate solution is placed on the membrane pad (50) for the supply of the substrate solution.

16. The membrane strip biosensor system in claim 15, wherein when the horizontal arrangement pads are fixed on to the vertical arrangement pads in a cross-position via automatic or manual handling of the flow transfer button (73) after the completion of a vertical flow reaction, the substrate solution container (76) is immediately broken by the substrate solution container-perforating needle (75) established in the bottom part (72) of the holder, thereby horizontal flow reaction is automatically conducted.