Systems and methods for fluorescence detection with a movable detection module

1. A fluorescence detection apparatus for analyzing samples located in a plurality of wells in a thermal cycler, the apparatus comprising:

a support structure attachable to the thermal cycler;

a shuttle movably mounted on the support structure; and

a detection module attached to the shuttle, the detection module including:

a housing having an opening oriented toward the plurality of wells;

an excitation light generator disposed within the housing; and

an emission light detector disposed within the housing,

wherein, when the support structure is attached to the thermal cycler, a heating element is disposed between the detection module and the sample wells and the shuttle is movable to position the detection module in optical communication with different wells of the plurality of wells through a plurality of openings extending through the heating element.

2. The fluorescence detection apparatus of claim 1 wherein an excitation optical path from the excitation light generator to the opening has a fixed length and a detection optical path from the opening to the emission light detector has a fixed length.

3. The fluorescence detection apparatus of claim 1 further comprising:

a calibration element disposed such that the detection module is movable so as to be positioned in optical communication with the calibration element,

wherein the calibration element provides a known fluorescence response.

4. The fluorescence detection apparatus of claim 3 wherein the calibration element is located between two or more of the plurality of wells.

5. The fluorescence detection apparatus of claim 3 wherein the calibration element is located in an area peripheral to the plurality of wells.

6. The fluorescence detection apparatus of claim 1 wherein positioning of the detection module with respect to the wells is controlled by an external computer.

7. The fluorescence detection apparatus of claim 1 wherein operation of the excitation light generator and the emission light detector is controlled by an external computer.

8. The fluorescence detection apparatus of claim 1 wherein the detection module is detachably attached to the shuttle.

9. The fluorescence detection apparatus of claim 1 wherein the excitation light generator comprises a light-emitting diode.

10. The fluorescence detection apparatus of claim 1 further comprising at least two stepper motors mounted on the support structure, the stepper motors being operative to move the shuttle in at least two dimensions.

11. The fluorescence detection apparatus of claim 1 wherein the detection module includes at least two emission light detectors.

12. The fluorescence detection apparatus of claim 1 wherein the detection module includes at least two excitation light generators.

13. A thermal cycler apparatus comprising:

a thermal cycler having an exterior housing and a plurality of sample wells for holding reaction vessels;

a heater to prevent condensation from forming on a surface of the reaction vessels when the reaction vessels are in the sample wells, the heater having a plurality of transparent portions to permit optical communication with each of the plurality sample wells;

a support structure disposed inside the exterior housing on an opposite side of the heater from the sample wells;

a shuttle movably mounted on the support structure; and

a detection module attached to the shuttle, the detection module including:

a module housing having an opening that is oriented toward the plurality of sample wells when the thermal cycler is in an operating state;

an excitation light generator disposed entirely within the module housing; and

an emission light detector disposed entirely within the module housing;

wherein, when the thermal cycler is in the operating state, the shuttle is movable to position the detection module in optical communication with different sample wells of the plurality of sample wells through the transparent portions of the heater.

14. The thermal cycler apparatus of claim 13 wherein the excitation light generator comprises a light-emitting diode.

15. The thermal cycler apparatus of claim 13 further comprising at least two stepper motors mounted on the support structure, the stepper motors being operative to move the shuttle in at least two dimensions.

16. The thermal cycler apparatus of claim 13 further comprising a fitting on an exterior surface of the housing of the detection module, the fitting adapted to attach the detection module to the shuttle, wherein the fitting provides only electrical and mechanical connections.

17. The thermal cycler apparatus of claim 13 wherein the detection module includes at least two emission light detectors.

18. The thermal cycler apparatus of claim 13 wherein the detection module includes at least two excitation light generators.

19. The thermal cycler apparatus of claim 13 wherein movement of the shuttle and operation of the excitation light generator and the emission light detector are controlled by an external computer such that emission light is measured while the shuttle is in motion.

20. The thermal cycler apparatus of claim 13 further comprising:

a plurality of optical components defining an excitation optical path for light of an excitation wavelength from the excitation light generator to the opening of the housing and a detection optical path for light of a detection wavelength from the opening of the housing to the emission light detector,

wherein all of the optical components of the excitation optical path and the detection optical path are disposed within the housing of the detection module.

21. The thermal cycler apparatus of claim 13 wherein the detection module is positioned such that the opening is below the plurality of sample wells.

22. The thermal cycler apparatus of claim 13 wherein the plurality of transparent portions of the heater includes a plurality of holes extending through the heater and aligned with the sample wells.