Table 2.1.
Photophysical properties of various photoswitchable molecules, including whether the fluorophore can be cycled between bright and dark states multiple times, absorption and emission peaks, and molar absorption coefficient, fluorescence quantum yield, photoconversion quantum yield, turn-on ratio, photobleaching quantum yield, and total photons emitted
| Reversible?a |
λabs/λem (nm) |
εmax (M−1 cm−1) |
Φ F | Φ P | Turn-on ratiob | Φ B | Ntot,e | |
|---|---|---|---|---|---|---|---|---|
| DCDHF-V-P-azide (Lord et al., 2008, 2010) |
No | 570/613 | 54,100 | 0.025–0.39c | Good (0.0059) |
Excellent (325–1270)d |
4.1 × 10−6 | 2.3 × 106 |
| DCDHF-V-PF4- azide (Lord et al., 2010; Pavani et al., 2009) |
No | 463/578 | 20,000 | 0.0062+ | Very good (0.017) |
9.2 × 10−6 | ||
| DCM-azide (Lord et al., 2010) |
No | 456/599 | 31,100 | 0.18 | Excellent (0.085) |
6.2 × 10−6 | ||
| Cy3/Cy5 + thiol (Bates et al., 2005; Conley et al., 2008; Huang et al., 2008b; Schmidt et al., 2002)e |
Yes | 647/662 | 200,000 | 0.18 | Very good | Excellent (≤1000)f |
~670,000 | |
| PC-RhBg | Yes | 552/580 | 110,000 | 0.65 | Moderate | ~600,000 | ||
| EYFP (Biteen et al., 2008 ; Tsien, 1998; Dickson et al., 1997 ; Harms et al., 2001 ; Patterson et al., 2001 ; Schmidt et al., 2002 ; Biteen et al., 2009)h,i |
Yes | 514/527 | 83,400 | 0.61 | Moderate (1.6×10−6) |
Moderate | 5.5 × 10−5 | ~140,000 |
| PAGFPj,k | No | 504/517 | 17,400 | 0.79 | Moderate (1.1×10−6) |
Moderate (100) |
~6 × 10−5 | ~140,000 |
| mEosFP (Gunewardene and Hess, 2008 ; Shroff et al., 2007 ; Wiedenmann et al., 2004)i,k |
No | 559/581 | 37,000 | 0.62 | Good (1.6×10−5) |
Very good | 3.0 × 10−5 | 21,000 |
| PAmCherry1 (Subach et al., 2009) |
No | 564/595 | 18,000 | 0.46 | Moderate (identical to PAGFP) |
Excellent (200–4000) |
||
| Dendra2 (Chudakov et al., 2007 ; Kremers et al., 2009 ; Subach et al., 2009)l |
No | 553/573 | 35,000 | 0.55 | Moderate (47) | |||
| Kaede (Ando et al., 2002; Kremers et al., 2009) |
No | 572/582 | 60,000 | 0.33 | Moderate (~10−4)m |
Moderate (28) | ||
| mOrange1/2 (Kremers et al., 2009 ; Shaner et al., 2004)n |
No | 615/640 | Poor (16) | |||||
| Dronpa (Ando et al., 2004 ; Habuchi et al., 2005)o |
Yes | 503/518 | 95,000 | 0.85 | Very good | ~3 × 10−5 |
All values are reported for the photoconverted form except photoconversion quantum yield.
Some fluorophores listed as irreversible may be reversible, but have yet to be reported as such.
Ratio of the fluorescence after and before photoactivation (see definition in text). Some papers report a “contrast ratio” of red to green fluorescence, which is the product of the n-fold increase in red fluorescence and n-fold decrease in the green fluorescence (Kremers et al., 2009); therefore, those reported contrasts are many times higher than the turn-on ratio, which is the relevant parameter for super-resolution imaging. Other papers report “contrast ratios” without definition, so we cannot confidently compare these values directly to turn-on ratio.
DCDHFs become brighter when rigidified (Lord et al., 2009; Willets et al., 2005).
This range corresponds to (Reff – R)
In the SI of reference Huang et al. (2008b) is reported only 0.1% spontaneous turn-on at ideal conditions (e.g., very high thiol and oxygen-scavenger concentrations). This value does not take into account the inherent on–off ratio of a single Cy5, so it is an upper limit.
Value estimated from photoconversion wavelengths, intensities, times, and spectra reported previously (Ando et al., 2002).