Real-time detection during gel electrophoresis
Adding Viridi stain to the agarose before running allows the DNA migration to be monitored during electrophoresis using a Dark Reader Hand Lamp.
The Dark Reader works with almost all of your favorite dyes
Dark Reader Technology can be used to detect many different fluorophors. In general, the ideal spectral characteristics for a `Dark Reader dye` are an excitation maximum between 420 – 500 nm and an emission maximum above about 520 nm.
The Dark Reader can also be effectively used to detect dyes that have maxima outside the above ranges. The only criterion is that at least a portion of the fluorescence excitation and emission fall within these ranges. Stated another way, the Dark Reader can be used to detect almost any dye excited in the visible range that does emit exclusively in the blue.
Choose Your Specific Application
Which dyes are best?
It is a commonly held misconception that for a fluorophor to work with the Dark Reader it must have an excitation maximum between 420 – 500 nm and an emission maximum above ~ 520 nm.
While these are useful guidelines, it should be emphasized that the DR can also be effectively used to detect fluorophors that have maxima well outside outside these ranges.
The more general criteria for visualizing a fluorophor with a Dark Reader transilluminator or hand lamp are:
- a PORTION of the excitation spectrum (ex) is between about 420 – 500 nm and
- a PORTION of the emission spectrum (em) is above about 520 nm.
More dyes than you'd think are compatible!
For example, consider the ex/em maxima of SYBR Green (494/521 nm) and RFP (558/583 nm) as shown in the image.
From the ex/em information alone, one would predict SYBR Green to work well (correct!), but RFP to be feeble (incorrect!).
In fact, RFP works very well – see the transgenic fish movie! The reason is evident from a more detailed consideration of the RFP excitation spectrum which reveals substantial excitation between 400 – 500 nm.