High Photostability of IRDye® 700DX
Photostability was tested by exposure to many sequential rounds of laser imaging.
Remains fluorescent after extended laser exposure
More photostable than other 700 nm dyes, including Alexa Fluor® 680li>
Substantially more photostable than tetramethylrhodamine (TMR), one of the most photostable fluorescent dyes.1
Figure 1. Equimolar amounts of each dye (25 fmol) were spotted onto nitrocellulose membrane. The membrane was scanned repeatedly with the Odyssey® Infrared Imaging System, and signal intensity was normalized to maximum intensity at time = 0.
Table 1. Photostability of IRDye 700DX, compared to other near-IR fluorescent dyes, and the very photostable TMR dye
|Dye||Irradiation intensity (W/cm2)||Intensity Gain factor at surface (Gi)||Absorption cross section σ01 (λ) (cm2)||Excitation rate constant k01 (λ) (excitation /sec)||Measured fluorescence decay rate kz (bleached dye/sec)||Mean number of survived excitation cycles µ|
|IRDye 700DX||24.711||2.823||6.200E-16 (680 nm)||1.479E+05 (680 nm)||0.024||>6.161E+6|
|Alexa Fluor 680||4.961||2.823||5.355E-16 (680 nm)||2.564E+04 (680 nm)||0.535||4.79E+04|
|Cy5.5||8.790||2.823||7.270E-16 (680 nm)||6.168E+04 (680 nm)||>0.454||1.36E+05|
|Cy7||27.449||2.823||3.440E-16 (780 nm)||1.045E+05 (780 nm)||0.794||1.317E+05|
|IRDye 800CW||17.475||2.823||9.180E-16 (780nm)||1.776E+05 (780 nm)||1.730||1.027E+05|
|TMR||25.073||2.823||2.340E-16 (531 nm)||4.422E+04 (531 nm)||0.191||2.32E+05|
1. X. Peng, D.R. Draney, W.M. Volcheck, G.R. Bashford, D.T. Lamb, D.L. Grone, Y.Zhang, C.M. Johnson, Phthalocyanine dye as an extremely photostable and highly fluorescent near-infrared labeling reagent., Proceedings of SPIE 6097, 2006.