Method of determining the viability of at least one cell

1. A method of determining the viability of a plurality of living human primary cells obtained from a single human donor for subsequent implantation into the single human donor via quantification of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H), flavin adenine dinucleotide (FAD), and/or collagen, said method comprising the steps of:

A. providing multi-layered tissue-engineered constructs with each construct including a surface layer, a middle layer containing the plurality of living human primary cells obtained from the single human donor, and a base layer;

B. contacting the plurality of living human primary cells of each construct with light having a wavelength of from 700 to 900 nm, using two photon excitation, or from 335 to 400 nm, using one photon excitation, to induce an optical response from the NAD(P)H, FAD, and/or collagen;

C. measuring the optical response;

D. quantifying one or more of an amount, spatial localization, and/or time-dependent response of the NAD(P)H, FAD, and/or collagen utilizing the optical response to identify viable cells of the plurality of living human primary cells; and

E. implanting one of the multi-layered tissue-engineered constructs containing the viable cells into the single human donor.

2. The method as set forth in claim 1 wherein the optical response is further defined as fluorescence.

3. The method as set forth in claim 1 wherein the optical response is further defined as second harmonic generation.

4. The method as set forth in claim 1 wherein the step of quantifying is further defined as quantifying an amount of NAD(P)H via measurement of fluorescence.

5. The method as set forth in claim 4 wherein second harmonic generation and FAD measurements are utilized to identify collagen and keratin background regions.

6. The method as set forth in claim 1 wherein the step of quantifying is further defined as quantifying an amount of FAD via measurement of fluorescence.

7. The method as set forth in claim 6 wherein second harmonic generation and FAD measurements are utilized to identify collagen and keratin background regions.

8. The method as set forth in claim 1 wherein the step of quantifying is further defined as ratiometrically analyzing a fluorescence intensity from NAD(P)H and FAD.

9. The method as set forth in claim 8 wherein second harmonic generation and FAD measurements are utilized to identify collagen and keratin background regions.

10. The method as set forth in claim 9 wherein the step of ratiometrically analyzing a fluorescence intensity is performed with a pair of measurements by calculating FAD/(NAD(P)H+FAD) at each pixel after excluding the collagen and keratin background regions.

11. The method as set forth in claim 1 wherein the step of quantifying is further defined as calculating a redox ratio of NAD(P)H and FAD.

12. The method as set forth in claim 1 wherein the step of quantifying is further defined as generating an en-face non-linear optical microscopy spatial image from a NAD(P)H fluorescence image.

13. The method as set forth in claim 12 wherein the step of generating an en-face spatial image is further defined as applying an image processing algorithm.

14. The method as set forth in claim 13 wherein the image processing algorithm is chosen from image denoising/enhancement, background removal, fractal analysis, and combinations thereof.

15. The method as set forth in claim 12 further comprising the step of applying a bi-exponential decay fitting algorithm and/or a phasor analysis algorithm to the en-face non-linear optical microscopy spatial image to determine a fluorescence lifetime image.

16. The method as set forth in claim 1 wherein the step of quantifying is further defined as resolving fluorescence decay measurements to quantify bound-NAD(P)H contributions to fluorescence lifetime.

17. The method as set forth in claim 16 wherein the step of resolving comprises selecting two collagen-free regions of NAD(P)H fluorescence that are void of collagen fluorescence and that have at least 100 photon counts in a peak channel.

18. The method as set forth in claim 17 further comprising the step of applying a least-squares iterative fit with a double exponential model to extract individual and average lifetimes and total contribution of a slow lifetime component.

19. The method as set forth in claim 18 wherein the total contribution is further defined as a contribution from bound-NAD(P)H and has a lifetime of from 1 to 4 nanoseconds.

20. The method as set forth in claim 1 wherein the step of quantifying is further defined as resolving fluorescence decay measurements to quantify average fluorescence lifetimes.

21. The method as set forth in claim 20 wherein the step of resolving comprises selecting two collagen-free regions of NAD(P)H fluorescence that are void of collagen fluorescence and that have at least 100 photon counts in a peak channel.

22. The method as set forth in claim 21 further comprising the step of applying a least-squares iterative fit with a double exponential model to extract individual and average lifetimes and total contribution of a slow lifetime component.

23. The method as set forth in claim 22 wherein the total contribution is further defined as a contribution from bound-NAD(P)H and has a lifetime of from 1 to 4 nanoseconds.

24. A method of determining the viability of a plurality of living human primary cells obtained from a single human donor for subsequent implantation into the single human donor via quantification of nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and/or flavin adenine dinucleotide (FAD), said method comprising the steps of:

A. providing multi-layered tissue-engineered constructs with each construct including a surface layer, a middle layer containing the plurality of living human primary cells obtained from a single human donor, and a base layer;

B. exciting the plurality of living human primary cells of each construct with light having a wavelength of from 700 to 900 nm, using two photon excitation, or from 335 to 400 nm, using one photon excitation, to induce fluorescence from the NAD(P)H and/or FAD;

C. measuring the fluorescence;

D. quantifying the presence of NAD(P)H and/or FAD utilizing the fluorescence to identify viable cells of the plurality of living human primary cells; and

E. implanting one of the multi-layered tissue-engineered constructs containing the viable cells into the single human donor.