Cotton thread as a low-cost multi-assay diagnostic platform

• US 8,206,992 B2
• Filed: 03/27/2009
• Issued: 06/26/2012
• Est. Priority Date: 03/27/2008
• Status: Active Grant

• Current Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Reches, Meital, Dickey, Michael D., Butte, Manish J., Whitesides, George M.
• Primary Examiner(s): Gakh, Yelena G
• Assistant Examiner(s): Xu, Robert
• Application Number:
  US12/934,702
• Publication Number:
  US 20110189786A1
• Time in Patent Office: 1,187 Days
• Field of Search: None
• US Class Current: 436/169
• CPC Class Codes: B01L 2200/0605 Metering of fluids
• CPC Class Codes: B01L 2200/10 Integrating sample preparation and analysis in single entity, e.g. lab-on-a-chip concept
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2300/0845 Filaments, strings, fibres, i.e. not hollow
• CPC Class Codes: B01L 2300/087 Multiple sequential chambers
• CPC Class Codes: B01L 2300/12 Specific details about materials
• CPC Class Codes: B01L 2300/161 Control and use of surface tension forces, e.g. hydrophobic, hydrophilic
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 3/5023 with a sample being transported to, and subsequently stored in an absorbent for analysis
• CPC Class Codes: B01L 3/5088 confining liquids at a location by surface tension, e.g. virtual wells on plates, wires B01L3/50857 takes precedence
• CPC Class Codes: G01N 33/54386 Analytical elements

Abstract

Hydrophilic threads as platforms for inexpensive, low volume, portable diagnostic systems, and methods of making the same are described. A diagnostic system includes a hydrophilic loading thread having an inlet zone at a proximal end; a testing zone at a distal end; and an intermediate zone located between the inlet zone and the testing zone, wherein the testing zone does not directly contact the inlet zone. In another aspect, a diagnostic system includes (i) a hydrophilic loading thread that includes an inlet zone at a proximal end and an intermediate zone at a distal end; and (ii) one or more additional hydrophilic threads that contact the intermediate zone of the loading thread. A method of detecting the presence or absence of an analyte in a fluid sample includes applying the sample to an inlet zone of a diagnostic system that includes a hydrophilic loading thread with an inlet zone at a proximal end; an intermediate zone; and a testing zone at a distal end; wherein the testing zone does not directly contact the inlet zone.

Claims

1. A system for performing an assay on a sample comprising one or more hydrophilic testing threads defining a sample inlet zone at a proximal end, an intermediate zone distal to the inlet zone through which fluid sample is carried by capillary action, and a testing zone distal to the intermediate zone and comprising a detection reagent which reacts with a predetermined analyte to produce a detectable signal.

2. The system of claim 1 further comprising a housing for support of the hydrophilic testing thread.

3. The system of claim 1, wherein the signal is detectable by a naked eye or a spectrometer.

4. The system of claim 2 wherein at least a portion of the hydrophilic testing thread is enclosed within the housing to protect the hydrophilic testing thread from contamination and mechanical damage.

5. The system of claim 2 wherein the housing comprises two faces, and the hydrophilic testing thread is sewn into the housing and exposed on each face.

6. The system of claim 2 wherein the testing zone is enclosed within and visible from outside the housing.

7. The system of claim 1 wherein the detection reagent is a colorimetric detection reagent.

8. The system of claim 1 comprising an array of hydrophilic testing threads for performing multiple assays on a biological sample.

9. The system of claim 1 comprising a portion of a bandage or cloth.

10. The system of claim 1 comprising a portion of a woven array of hydrophilic testing threads.

11. The system of claim 2 comprising a portion of a woven array of hydrophilic testing threads.

12. The system of claim 1 wherein a said hydrophilic testing thread comprises multiple testing zones or multiple inlet zones.

13. The system of claim 2 wherein a said hydrophilic testing thread comprises multiple testing zones or multiple inlet zones.

14. The system of claim 1 for performing multiple assays on a sample further comprising

a housing, a hydrophilic loading thread comprising an inlet zone outside the housing, where one or more said hydrophilic testing threads communicate with said loading thread and at least a portion of the testing threads is enclosed within the housing.

15. The system of claim 14 further comprising in a said testing zone a detection reagent which reacts with a predetermined analyte to produce a signal apparent to the naked eye.

16. The system of claim 14 wherein at least two testing zones comprise different detection reagents.

17. A method of detecting an analyte in a fluid sample, the method comprising contacting an inlet zone of a system of claim 1 with a sample to induce sample flow by capillary action to a said testing zone and visually observing a signal at said testing zone.

18. The method of claim 17 comprising visually observing a plurality of signals at multiple detection zones.