How does ethidium bromide stain nucleic acids

Sensitivity is the same as Method I, and may require destaining in water or 1mM MgSO 4 to achieve the best sensitivity. In this method, bands become visible from the top and bottom of the gel as the dye diffuses into the matrix. High contrast results can often be achieved without destaining by soaking the gel until the top and bottom of the bands appear, and then leaving the gel to stand out of the staining solution for minutes. During this time the stain will continue to diffuse into the gel, binding to the DNA at the expense of free dye.

The result is a lower background without destaining. Always use plastic wrap under ethidium stained gels to avoid solarization damage to the surface of the transilluminator. All rights reserved. Please read our policies on privacy, shipping and returns. Skip to main content. Log In To My Account.

Ethidium Bromide Staining. Bands in gels stained with Ethidium Bromide fluoresce under ultraviolet light. Add EtBr to 0. Pour gel and allow to set as usual. This solution is stable for months at room temperature in the dark. After the run submerge the gel in the staining solution for minutes depending upon gel thickness.

Place the gel on plastic wrap on a UV light box and observe under nm illumination. Bands will appear bright orange on a pale orange background. While it is an effective tool for genomic research, its hazardous properties require special safe handling and disposal.

EtBr is a potent mutagen can cause genetic damage , and moderately toxic after an acute exposure. EtBr can be absorbed through skin, so it is important to avoid any direct contact with the chemical.

The powder form is considered an irritant to the upper respiratory tract, eyes, and skin. Even though there is no evidence at this time of human carcinogenicity or teratogenicity, this material should be considered a possible carcinogen or teratogen.

Some alternative stains have been found to be less mutagenic and less toxic than EtBr. If the toxicological data is lacking or unclear, the stain should be handled in the same way as EtBr.

Some alternative stains are suspended in dimethyl sulfoxide DMSO , which has health implications of its own, including increased skin absorption of organic compounds. Maintaining overall good laboratory work practices helps reduce the risks of hazardous exposures. Work in a fume hood when handling powders, crystals, or solutions, in order to prevent inhalation exposure. Wear a lab coat, long pants, closed-toe shoes, eye protection Safety Glasses or Goggles , and nitrile or chloroprene gloves when working with EtBr.

Leave lab coats, gloves, and other PPE in the lab, when your work is complete, to prevent the spread of this or other chemicals outside of the lab. Transport in secondary containment and work with small quantities of EtBr to minimize the risk of accidents.

Careful housekeeping is necessary when working with DNA stains. Delineate and restrict the area in which DNA stains may be used. Check other areas with UV light in a darkened room and follow the decontamination procedures below for contaminated surfaces. When an ultraviolet light source is used with EtBr procedures, added caution is required. As a general rule, avoid exposing unprotected skin and eyes to intense UV sources. If the UV light is aimed upwards, wear a UV protective face shield when you are standing near the source.

For prolonged work close to UV light boxes or other intense sources, it may be useful to wrap the end of the lab coat sleeves loosely with masking tape to prevent gaps where the wrist could be exposed.

Ethidium bromide should be stored away from strong oxidizing agents in a cool, dry place, and the container must be kept undamaged and tightly closed. Several alternatives to EtBr exist which manufacturers claim are less toxic than EtBr and may not require UV light sources.

The following represent a few of the available alternatives to EtBr:. MaestroSafe products are non-carcinogenic by the Ames-test.

The results are negative in both the mouse marrow chromophilous erythrocyte micronucleus and mouse spermary spermatocyte chromosomal aberration tests.