Illuminator

What are they and why do we use them? What types are there?

An illuminator is a device that releases light in a specific spectrum or set of spectra. It is used for the Gel Illumination and Photography protocols to fluoresce DNA in an agarose gel at the correct wavelength for the intercalated dye that you’ve chosen. It may be part of an all-in-one device with an imaging enclosure and camera (such as the Chemidoc XRS above) or you can build one separately to give you more control over the imaging device and environment.

I personally find a smartphone camera to be far better than any of the cameras sold in industrial illumination devices. Likewise the proprietary software required to operate them is as prohibitively expensive as it is useless at optimising images. However the all-in-one imagers and enclosures are far safer, UV light is carcinogenic and you need to be able to trust that all UV light is being contained if you’re working with it.

The main variation you’ll find in illuminators is the wavelength of light that is emitted. This needs to match a peak in the adsorption spectrum of your chosen DNA intercalating dye. LEDs will work for visible wavelength light but you will likely need to get special fluorescent bulbs if you wish to image in the UV spectrum.

When do you use?

After agarose electrophoresis you will use this device to illuminate your gel for imaging and analysis.

How do you use?

Caution: Short wavelength UV light is carcinogenic! Design a proper imaging enclosure before using any device that emits UV light. Even if you trust your imager, you should wear long sleeves and plane-polarised sunglasses while operating a UV imager.

Place your gel in the tray, close the imaging enclosure, turn on the light, snap some pics. Turn everything off and observe your pictures. Make adjustments and take more if necessary. Proprietary machinery will likely have fiddly software for the photography, which is why I prefer to use a smartphone camera for photography.