Diagnostic detection device and method
View Patent ↗The invention provides an improved test cell for detecting the presence of an analyte in a liquid sample. The device has an elongate casing defining a liquid sample inlet, a reservoir volume, a test volume, and a window through the casing at the test volume. Disposed within the cell is a sample absorbent, a novel biphasic substrate and a reservoir, together capable of transporting an aqueous solution within the casing along a flow path extending from the sample inlet through the test volume and into the reservoir volume. The invention further comprises a method for detecting the presence of an analyte in a liquid sample using the device and a biphasic chromatographic material for carrying out the method.
1. A device for determining the presence in a liquid sample of an analyte wherein liquid sample deposited on a proximal end of the device travels downstream along a liquid path to a distal end of the device, the device comprising:
a biphasic substrate comprising (1) a release medium of a first material and, in fluid communication and downstream thereof, (2) a capture medium of a microporous, second, different material,
wherein located at the release medium of the biphasic substrate for release therefrom is
(i) a labeled conjugate comprising a binding member reactive with a first epitope of the analyte labeled with a detectable marker, and
(ii) a capturable component reactive with a second epitope of the analyte, such that if the analyte is present in the sample, the analyte produces a complex comprising the labeled conjugate, the analyte and the capturable component, and
located at the capture medium of the biphasic substrate is
a capture site for capturing the complex, the capture site having immobilized thereon a capture component having a binding affinity for the capturable component.
2. The device of claim 1 further comprising a control site located downstream of the capture site, the control site having immobilized thereon an agent having a binding affinity for the labeled conjugate.
3. The device of claim 1 wherein the capture medium is laminated to or cast on a transparent polymeric material.
4. The device of claim 1 comprising a sample absorbent located upstream of the biphasic substrate at the proximal end of the device.
5. The device of claim 1 further comprising a residual absorbent located downstream of the biphasic substrate at the distal end of the device.
6. The device of claim 1 wherein the binding member of the labeled conjugate is an antibody.
7. The device of claim 1 wherein the capturable component is a biotinylated antibody.
8. The device of claim 7 wherein the immobilized capture component comprises avidin, streptavidin or an antibiotin antibody.
9. The device of claim 1 wherein the immobilized capture component comprises avidin, streptavidin, or an antibiotin antibody.
10. The device of claim 1 wherein the second material of the biphasic substrate is nitrocellulose or nylon.
11. The device of claim 1 wherein the first material of the biphasic substrate is absorbent paper.
12. The device of claim 1 wherein the release medium and the capture medium of the biphasic substrate are both immobilized on a single backing support.
13. A device for determining the presence in a liquid sample of an analyte wherein liquid sample deposited on a proximal end of the device travels downstream along a liquid path to a distal end of the device, the device comprising:
a biphasic substrate comprising (1) a release medium of a first material and in fluid communication and downstream thereof, (2) a capture medium of a second, different material of nylon or nitrocellulose, wherein the release medium and the capture medium are both immobilized on a single backing support,
wherein located at the release medium of the biphasic substrate for release therefrom is
(i) a labeled conjugate comprising a first antibody that binds a first epitope of the analyte labeled with a detectable marker, and
(ii) a capturable component comprising a biotinylated second antibody that binds a second, different epitope of the analyte, such that if the analyte is present in the sample, the analyte produces a complex comprising the labeled conjugate, the analyte and the capturable component, and
located at the capture medium of the biphasic substrate is
a capture site for capturing the complex, the capture site having a capture component immobilized thereon for biding the capturable component.
14. The device of claim 13 further comprising a control site located downstream of the capture site, the control site having immobilized thereon an agent having binding affinity for the labeled conjugate.
15. The device of claim 13 , wherein the capture medium is laminated to or cast on a transparent polymeric material.
16. The device of claim 13 further comprising a sample absorbent located upstream of the biphasic substrate at the proximal end of the device.
17. The device of claim 13 further comprising a residual absorbent located downstream of the biphasic substrate at the distal end of the device.
18. The device of claim 13 , wherein the first material of the biphasic substrate is absorbent paper.
19. The device of claim 13 , wherein the capture component is avidin or streptavidin.