Applications

Highly sensitive DNA detection in gel

Using a unique combination of filters, the Dark Reader is at least as sensitive as a UV transilluminator for the detection of many dyes. For example, using SYBR Gold stain it is possible to see, by eye, less than 100 pg of DNA.

Detection of fluorophores in plastic

All our Dark Reader products, including the Hand Lamps, are particularly effective for viewing fluorophors in places where UV light cannot reach – through glass and plastic.

Detect fluorescently-transformed bacterial colonies

Using a Dark Reader transilluminator, the fluorescence from EYFP expression in bacterial colonies is easily detectable. Picking the correct colony has never been easier!

Real-time detection during gel electrophoresis

Adding a fluorescent DNA stain to the agarose before running, allows the DNA migration to be monitored during electrophoresis using a Dark Reader Hand Lamp.

Monitor protein expression in transgenic animals or plants

Our customers have used Dark Reader Hand Held Lamps to visualize fluorescence in fish, mice, sheep, corn, leaves, seedlings and silkworm coccoons!

Very sensitive protein detection in gels/membranes

The Dark Reader technology can detect as low as 2ng of protein with the use of SYPRO Ruby.

The Dark Reader works with almost all of your favorite dyes

Table of dyes according to their compatability with Dark Reader
Table of dyes according to their compatability with Dark Reader

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.
Image of tubes glowing under dark reader lamp

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.

Image of SYBR green vs RFP

If you are still uncertain about your particular application, please send us an email and we will advise on whether a Dark Reader is suitable or even arrange for you to try one of our demo units!