Ethidium bromide (EB) A trypanocidal agent and possible antiviral agent that is widely used in experimental cell biology and biochemistry. Ethidium has several experimentally useful properties including binding to nucleic acids, noncompetitive inhibition of nicotinic acetylcholine receptors, and fluorescence among others. It is most commonly used as the bromide. Ethidium bromide has a λEx of 300-360 nm and a λEm of 590 nm.

Instructions
1. Solution preparation: Prepare agarose gel of appropriate concentration (usually 0.5% to 2.5%) according to the size of the band to be separated.
2. Operation steps
1. Accurately weigh a certain amount of agarose powder and mix it with a certain amount of 1X TAE/TBE.
2. Heat in a microwave oven for 1-3 minutes until the agarose is completely dissolved.
3. Shake the melted agar solution to mix well, pour it into the electrophoresis tank, and wait for it to solidify;
4. Add Ethidium bromide (EtBr) to a final concentration of about 0.2-0.5 μg/mL (the stock solution is usually 10 mg/mL, and 5 μL of stock solution/100 mL of gel is required);
5. Ethidium bromide binds to DNA, and DNA can be visualized under ultraviolet (UV) light.