Table 1.
Photophysics of ICG in various media.
| Solvent | λmax,abs [nm] | ε [M−1 cm−1] | λmax,em [nm] | ΦF [%] | Brightness[g]×104 [M−1 cm−1] | SWIR emission, α[h] [%] | SWIR brightness[i]×104 [M−1 cm−1] | Photobleaching rate kraw×103 [s−1] | Relative photostability |
|---|---|---|---|---|---|---|---|---|---|
| EtOH | 787 | 223 000 ± 6 000 | 815 | 14 ± 1 | 310 ± 20 | 1.44 | 4.5 ± 0.3 | 0.98 ± 0.09 | 16 ± 1 |
| Water | 779 | 156 000 ± 6 000 | 805 | 2.9 ± 0.2 | 45 ± 4 | 0.71 | 0.32 ± 0.03 | 15.5 ± 0.2 | 1 |
| FBS[a] | 798 | 162 000 ± 3 000 | 811 | 12.0 ± 0.9 | 190 ± 20 | 1.43 | 2.8 ± 0.2 | 3.85 ± 0.05 | 4.03 ± 0.06 |
| Micelles[b] | 796 | 180 000± 8 000[e] | 821 | 5.1 ± 0.3 | 92 ± 7 | 0.99 | 0.91 ± 0.07 | 14.2 ± 0.4 | 1.09 ± 0.03 |
| Whole blood[c] | 788[d] | n.r.[f] | 815 | 13 ± 1 | n.r. | 5.15 | n.r. | 8.4 ± 0.3 | 1.84 ± 0.06 |
[a]
FBS=Fetal bovine serum.
[b]
18:0 PEG2000 PE micelles dispersed in water.
[c]
Defibrillated sheep blood.
[d]
1:1 whole blood:saline was used due to high scattering in whole blood.
[e]
An apparent absorption coefficient is used, as described in the experimental procedures.
[f]
High scattering prevented absorption coefficient measurements in this media.
[g]
Brightness=ɛ×ΦF.
[h]
SWIR emission (α); α=emission between 1,000–1,350 nm/total emission×100.
[i]
SWIR brightness=brightness×(α/100).