Preparation of tissue sections using fluorescence-based detection

1. A method of determining the location of a tissue in an embedded sample, the method comprising:

irradiating an embedded sample with light having a wavelength of from about 200 nm to about 600 nm, wherein the embedded sample comprises a tissue and an embedding medium;

detecting fluorescence emission of the embedded sample; and

determining the location of at least a portion of the tissue in the embedded sample based on the fluorescence emission.

2. The method of claim 1 , wherein the embedding medium is a paraffin.

3. The method of claim 1 , wherein the embedded sample is a formalin-fixed paraffin-embedded (FFPE) tissue block.

4. The method of claim 1 , wherein the fluorescence emission is detected using an imaging device comprising a camera.

5. The method of claim 4 , wherein a digital image of the fluorescence emission is used to determine the location of the tissue in the embedded sample.

6. The method of claim 5 , wherein pixel intensity of the digital image is used to determine the location of the tissue in the embedded sample.

7. The method of claim 1 , wherein the method is used to determine the location of a tissue surface.

8. The method of claim 7 , further comprising slicing or trimming a section from the embedded sample after determining the location of the tissue surface.

9. The method of claim 8 , wherein the method comprises staining the tissue section with at least one stain.

10. The method of claim 1 , wherein the light has a wavelength of from about 250 nm to about 450 nm.

11. The method of claim 1 , wherein the fluorescence emission is generated by autofluorescence of a component of the tissue.

12. The method of claim 11 , wherein the component is elastin or collagen.

13. A method of determining the location of a tissue in an embedded sample, the method comprising:

irradiating an embedded sample comprising a tissue and an embedding medium with at least one light source to produce a first fluorescence emission and a second fluorescence emission;

detecting the first fluorescence emission and the second fluorescence emission; and

determining the location of at least a portion of the tissue in the embedded sample based on the first fluorescence emission and the second fluorescence emission.

14. The method of claim 13 , wherein the embedded sample is irradiated by at least two light sources.

15. The method of claim 13 , wherein the embedded sample is a formalin-fixed paraffin-embedded (FFPE) tissue block and the first fluorescence emission occurs via fluorescence of paraffin.

16. The method of claim 13 , wherein the method comprises front illuminating the embedded sample transversely.

17. The method of claim 13 , wherein the embedded sample is front-illuminated at an oblique angle of from about 10 degrees to about 20 degrees from a plane of a face of the embedded sample.

18. An apparatus for slicing a tissue section from an embedded sample, the apparatus comprising:

a microtome comprising a sample holder adapted for linear motion, a knife holder and a knife held by the knife holder opposite the sample holder, such that when the sample holder is moved linearly, a sample held by the sample holder is sliced by the knife to form a tissue section;

at least one light source directed at the sample holder;

an optical system positioned to capture emitted light from a sample held by the sample holder; and

a processor in communication with the optical system and configured to provide a signal based on a fluorescence emission from the sample, wherein a location of the tissue section of the embedded sample is determined based on the fluorescence emission.

19. The apparatus of claim 18 , wherein the optical system comprises a camera.

20. The apparatus of claim 18 , wherein said light source provides light having a wavelength of from about 200 nm to about 600 nm.