PHOTO-ACOUSTIC DETECTION DEVICE AND METHOD

• US 20090170149A1
• Filed: 12/31/2008
• Published: 07/02/2009
• Est. Priority Date: 07/11/2006
• Status: Active Grant

• Current Assignee: Curators of the University of Missouri (University of Missouri)
• Original Assignee: Curators of the University of Missouri (University of Missouri)
• Inventors: Weight, Ryan M., Sutovsky, Peter, Viator, John A., Dale, Paul S.
• Granted Patent: US 8,501,099 B2
• Time in Patent Office: Days
• US Class Current: 435/29
• CPC Class Codes: G01N 21/1702 with opto-acoustic detection, e.g. for gases or analysing solids

Abstract

An example system for detecting an analyte in a sample of a bodily fluid comprises a test chamber having at least one sidewall and configured to contain at least a portion of a bodily fluid sample, an excitation electromagnetic energy source configured to direct an energy source into the test chamber through the at least one sidewall and to induce a thermoelastic expansion in the one or more analytes, and a sensor configured to detect said thermoelastic expansion in the bodily fluid sample in the test chamber, the sensor configured to measure changes in optical reflectance that result from the thermoelastic expansion.

Claims

1. A system for detecting one or more analytes in a bodily fluid comprising:

a test chamber having at least one sidewall and configured to contain at least a portion of a bodily fluid sample;

an excitation electromagnetic energy source configured to direct an energy source into the test chamber through the at least one sidewall and to induce a thermoelastic expansion in the one or more analytes; and

,

a sensor configured to detect said thermoelastic expansion in the bodily fluid sample in the test chamber, the sensor configured to measure changes in optical reflectance that result from the thermoelastic expansion.

2. A system as defined by claim 1 wherein the sensor comprises a light source for directing a light beam at a reflecting interface and a receiver for receiving the reflected light beam and determining that a disruption to the beam has occurred.

4. A system as defined by claim 2 wherein the detector further comprises one or more lenses for focusing the light beam, the one or more lenses arranged between the light source and the receiver.

5. A system as defined by claim 2 and further comprising a transparent liquid layer adjacent to the test chamber and a transparent solid interfacing with the transparent liquid layer, wherein the photoacoustic event causes the index of refraction at the interface between the liquid layer and solid to change.

6. A system as defined by claim 5 wherein the transparent solid comprises a glass prism, the transparent water layer on a first side of the prism, the detector light source directing the light beam into a second side of the prism towards the prism first side, and the reflected light beam passing through a third sidewall of the prism and to the sensor.

7. A system as defined by claim 1 wherein the sensor further comprises a detection laser beam source, and further comprising a water layer adjacent to the test chamber and a glass layer interfacing with the water layer, the glass layer reflecting the laser beam from the laser beam source.

8. A system as defined by claim 1 wherein the sensor further comprises a source for directing a light beam towards the flow chamber, a liquid layer adjacent to the flow chamber, and a detector for receiving the detector light beam after reflection at a surface of the liquid layer.

9. A system as defined by claim 8 wherein the sensor light source is arranged to cause the light beam to be incident on the liquid layer at an angle close to the critical angle of total reflection.

10. A system as defined by claim 9 wherein the sensor light source is arranged to cause the light beam to be incident on the liquid layer at an angle that is close to the critical angle of total reflection.

11. A method for detecting an analyte as defined by claim 1 wherein the step of detecting said photoacoustic signal comprises detecting a thin film deflection through detecting a change in a light beam reflection.

12. A system as defined by claim 1 and further including a computer having a memory with linear regression data stored on the memory, the computer communicating with the sensor, the computer configured to receive a detection signal from the sensor and use the data on the memory to calculate a concentration level of material in the bodily fluid sample and to communicate that concentration level to one or more of a display for displaying and to a memory for storing.

13. A system as defined by claim 1 wherein the bodily fluid sample is flowing through the test chamber, and wherein the electromagnetic energy source is a beam directed through the test chamber and having a diameter that extends across the entire width of the test chamber wherein no portion of the flowing fluid sample escapes illumination by the beam.

14. A system as defined by claim 1 wherein:

the excitation electromagnetic energy source comprises a laser pulsing at a frequency faster than a millisecond; and

,

the bodily fluid sample has a residence time in the test chamber of sufficient to all for at least 10 pulses of the laser.

15. A system as defined by claim 1 and further comprising:

a reservoir, a conduit, and a pump, the reservoir communicating with the test chamber via the conduit, the pump arranged along the conduit to urge the sample from the reservoir to the test chamber and configured to cause the analyte to flow at a first flow rate and cause a first residence time of analyte in the test chamber; and

,

wherein the excitation energy source comprises a pulsed laser operating at a frequency that is faster than the first residency time.

16. A system as defined by claim 15 wherein the frequency is at least four times greater than the residence time.

17. A system as defined by claim 1 wherein the excitation energy source comprises a beam having a diameter that extends across all of the diameter of the sample in the test chamber so that no portion of the sample escapes illumination by the beam.

18. A system as defined by claim 1 wherein the system is configured to test a sample as it flows through the test chamber, the system further comprising:

a downstream conduit for carrying analyte fluid from the test chamber to a reservoir;

a bypass provided along the conduit for bypassing a portion of the analyte fluid that contains a pathogen to a collection cell; and

,

a controller for causing only a portion of the analyte that contains the pathogen to be directed through the bypass to the collection cell.

19. A system as defined by claim 18 wherein the controller comprises a computer with executable instructions that determine the period of time it will take for the analyte to the bypass and is configured to cause the bypass to remain open to collect a small portion of the analyte that contains the pathogen.

20. An in vitro flow system for detecting one or more circulating cancer cells comprising:

a test chamber in communication with a conduit;

a pump urging a bodily fluid sample to flow through the conduit and through the test chamber,

a pulsing excitation laser source that directs a laser beam into the test chamber and illuminates an entire cross section of the flowing bodily fluid sample as it flows through the test chamber and operating a frequency that is greater than the residence time of the bodily fluid sample in the test chamber;

a sensor comprising;

a transparent solid sandwiching a thin water layer between it and the test chamber;

a detection laser source directing a laser beam into the transparent solid and reflecting from the interface of the solid and thin water layer; and

,

a receiver that receives the laser beam reflected from the transparent solid and water interface and that measures a disturbance in the reflected laser beam when a change in the refractive index of reflection occurs when a wave travels through the thin water layer.