LEDs have an emission wavelegth > 400 nm and are therefore not suitable for ethidium bromide (excitation wavelength 300 nm). They will be OK for SybrSafe, provided that the camera is fitted with the adequate filter (blocking light < 500 nm). See excitation/emission spectra of the dyes you are planning to use (easy to find on the Internet using Google).

There are 4 main aspects that need consideration.

Safety, Price, Sensitivity and usage.

My feeling is that ETBR is safe. It is used in gramme quantities treating cows with trypanosomes and nobody has reported tumours in the cows, calves or in people eating the meat so the safety aspect for me is the UV light.Modern systems are enclosed so this is not much of a problem unless you are spending a lot of time cutting bands out of agarose gels. UV light does have the additional problem of photobleaching where your signal disappears if illuminated too long due to degradation of the dna and chromophore. If you are doing large amounts of sensitive cloning then damage caused by uv light compared with blue light may be an issue for you.

Both ETBR and SYBR safe will pick up amounts of dna between 1 and 5 ng of DNA but gel red should be capable of seeing 0.25ng. The cost of using the dyes is approximately etbr 0.001 £ per 100ml,

Sybr safe is about 0.9 £ per 100ml and gel red about 1.9 £ per 100ml so the cost of dyes over a year is very much higher with newer dyes.

All of the dyes intercalate so will be weaker with shorter pcr fragments awhich also diffuse with heat and distance run in the gel so running gels a short distance atlow voltage and cool temperature will give better results fo 25-50 mers products.

Another aspect of cost is the replacement cost of uv bulbs but the initial cost of equipment and spares depends on the discount that you get for your university so I cannot comment.

As Pierre mentions, it all depends upon the excitation wavelength of the dye that you intend to use. You need a light source that emits at that wavelength and does not emit (or is filtered out) at the emission wavelength of the dye so that you can detect the emission.

Hi Aref!

Did you change your transilluminator UV for LED one? Could you please let me know your opions? I'm looking to buy a new one and I thinking about this possibility.

Thanks in advance

Cyan LED´s are suitable for ethidium bromide, because it has 2 absorption peaks. Just look at the spectra. The second one is much smaller though... But this is no problem at all, if you use a lot! of LED power.

We are very happy with our new cyan one. Every dye works :)

Michel Seiwert can you please explain better? I've tried looking at the emission spectrum of cyan LED's and do not see any significant emission in the UV range below 350nm that one would use for ethidium bromide/DNA excitation.

Look at the spectra from wiki

https://de.wikipedia.org/wiki/Ethidiumbromid#/media/Datei:Ethidium-bromide-abs_DE.svg )

there is a small absorption peak around 480 nm (kinda small compared to the peak at 300 nm).

We are using this transilluminator > https://www.nippongenetics.eu/de/produkt/blaugruen-led-transilluminator/

Works perfect. And if you are a little bit into electronics and led lightning, you can easily build it by yourself.

But you will need a lot (30-60W) raw LED power (because of the small peak)