METHOD AND APPARATUS FOR DETECTION OF ANALYTES

• US 20100141938A1
• Filed: 12/10/2008
• Published: 06/10/2010
• Est. Priority Date: 12/10/2008
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Rapol, Umakant Damodar, Pietzykowski, Matthew Damian, Maity, Sandip, Banerjee, Ayan
• Application Number:
  US12/331,713
• Publication Number:
  US 20100141938A1
• Time in Patent Office: Days
• US Class Current: 356/246
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 2021/6417 Spectrofluorimetric devices
• CPC Class Codes: G01N 21/03 Cuvette constructions
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 2201/0691 Modulated (not pulsed supply)

Abstract

A microfluidic detection system is provided. The system comprises a device for illuminating a microfluidic sample comprising an analyte, wherein illumination from the illuminating device is modulated on and off at a determined frequency, a gated phase-sensitive detector that detects, one or more wavelengths emitting from the analyte, at a determined frequency, and a control device that coordinates the modulating frequency of the illumination and the detecting frequency of the detector.

Claims

1. A microfluidic detection system, comprising:

a device for illuminating a microfluidic sample comprising an analyte, wherein illumination from the illuminating device is modulated on and off at a determined frequency;

a gated phase-sensitive detector that detects, one or more wavelengths emitting from the analyte, at a determined frequency; and

a control device that coordinates the modulating frequency of the illumination and the detecting frequency of the detector.

2. The microfluidic detection system of claim 1, wherein the illuminating device modulates on and off at a determined frequency.

3. The microfluidic detection system of claim 1, comprising an intermittent illumination device to at least partially interrupt the illumination from the illuminating device.

4. The microfluidic detection system of claim 1, wherein the gated phase-sensitive detector comprises a photodiode or a CCD and a lock-in amplifier.

5. The microfluidic detection system of claim 1, wherein the detection frequency is determined at least in part based on the frequency of modulation of the illuminating device.

6. The microfluidic detection system of claim 5, wherein the detector detects only when the illuminating device is off.

7. The microfluidic detection system of claim 6, wherein the illuminating device illuminates along a direction line and wherein the detector detects, at least in part, along a direction line that is in-line with the illuminating device'"'"'s direction line.

8. The microfluidic detection system of claim 1, wherein the illuminating device comprises a laser, a light emitting diode (LED), a fluorescent lamp, or combinations thereof.

9. The microfluidic detection system of claim 8, wherein the photodiode is an avalanche photodiode.

10. The microfluidic detection system of claim 8, wherein a rise time of the photodiode is in a range from about 2 nanoseconds to about 5 nanoseconds

11. The microfluidic detection system of claim 1, wherein a sensivity of the gated phase-sensitive detector is greater than about 50 nanovolts.

12. The microfluidic detection system of claim 1, wherein the detector is in a direction of excitation of the analyte.

13. A microfluidic detection system for detecting a signal corresponding to an analyte, comprising:

a device for illuminating a microfluidic sample comprising an analyte, wherein illumination from the illuminating device is modulated on and off at a determined frequency;

a gated phase-sensitive detector that detects one or more wavelengths emitting from the analyte at a determined frequency; and

a control device that coordinates the modulating frequency of the illumination and the detecting frequency of the detector.

14. The microfluidic detection system of claim 13, wherein a concentration of analyte is greater than or equal to about 3 nanomolar.

15. The microfluidic detection system of claim 13, wherein a signal to noise ratio is enhanced by a factor in a range from about 3 to about 10.

16. A detection system for detecting a signal corresponding to an analyte, comprising:

a sample support comprising a sample detection zone;

a device for illuminating the sample in the detection zone, wherein the illuminating devices modulates on and off; and

a gated phase-sensitive detector for detecting the signal at a determined frequency when the illuminating device is off.

17. The detection system of claim 16, further comprising a control device that coordinates the modulation of the illuminating device and the detecting frequency of the detector based at least in part on a determined time delay interval between when the illumination source is on and when the detector begins detecting.

18. The detection system of claim 17, wherein the determined time delay interval is about 1 nanosecond to about 2.5 nanoseconds.

19. The detection system of claim 16, further comprising a low-wavelength pass optical filter disposed between the sample detection zone and the detector.

20. The detection system of claim 16, wherein at least one of the analyte is coupled to a phosphor dye.

21. The detection system of claim 16, wherein the sample support comprises a microfluidic device.

22. The detection system of claim 16, wherein the gated phase-sensitive detector comprises a heterodyne lock-in amplifier.

23. A method for signal detection of an analyte in a sample provided on a support, comprising:

illuminating the sample;

ceasing illumination of the sample after a determined time interval; and

after a time delay period, begin detecting a signal emitted from the sample at one or more lock-in detection frequencies.

24. The method of claim 23, further comprising filtering the signal emitted from the sample.

25. The method of claim 23, wherein the sample comprises a fluorescent probe and wherein the determined time interval is greater than or equal to a fluorescence lifetime of the fluorescent probe.