Table 2. Fluorescence emission parameters for different blood cells and blood plasma.
| Cell type | Intensity (ex/em), a.u. |
Lifetime, ns | Notes | |||
|---|---|---|---|---|---|---|
| 405/450 | 405/525 | 488/610 | 488/690 | |||
| Neutrophils | 2.1 ± 0.5 | 1.4 ± 0.3 | 1.5 ± 0.4 | 2.9 ± 1.4 | 1.25 ± 0.15 | Biexponential decay at 402 nm excitation caused by enzyme-bound flavins |
| Monocytes | 1.4 ± 0.4 | 1.0 ± 0.3 | 1.1 ± 0.3 | 1.5 ± 0.7 | – | |
| Lymphocytes | 0.7 ± 0.2 | 0.6 ± 0.2 | 0.6 ± 0.2 | 0.5 ± 0.4 | – | |
| Eosinophils | 12 | 7.1 | 19.8 | 34 | 0.9 ± 0.1 | Highly fluorescent cells with red shifted emission |
| EryPC | 1.2 ± 0.4 | 0.8 ± 0.3 | 3.5 ± 2.6 | 21 | 0.7 ± 0.1 | High fluorescence in the red region of spectrum with a fast fluorescence decay caused by hemoglobin degradation products |
| RBC | 0.5 ± 0.2 | 0.4 ± 0.1 | 0.6 ± 0.2 | 1.1 ± 0.9 | ∼IRF | Weak ultrafast fluorescence emission caused by the formation of hemoglobin photoproduct |
| Blood plasma | - | - | - | - | 1.1 ± 0.2 | Background signal comparable to that of WBCs at 405 and 488 nm excitation |