Thus, as a first line of defence, an innovative structure was used for the gel stain molecule making it extremely difficult to cross cell membranes. In addition, it was recognised that once a DNA dye enters a cell it might be subject to metabolism which could convert the dye into a chemical that could be either more mutagenic as in the case of ethidium bromide or less mutagenic than the unmetabolised original.
Thus, as a second line of defence, chemical bonds were incorporated at strategic positions in the dye molecule so that on enzymatic cleavage the dyes will become very weak DNA-binding molecules.
Using the standard Ames test, as measured in two bacterial strains, both GelRed and GelGreen were confirmed to be substantially safer than ethidium bromide see box. It is believed these unique structural features are at least partially responsible for the observed low mutagenicity and low cytotoxicity of GelRed and GelGreen.
But does improving safety mean compromising on results? Figure 1: Agarose gels precast with GelRed or ethidium bromide Sensitivity: as shown in Figure 1, GelRed is significantly more sensitive than ethidium bromide in precast gels for detection of low-level DNA, especially in the lower molecular weight area. Stability: both GelGreen and, in particular, GelRed are so stable that the 10,x stock solutions of the dyes can be routinely stored at room temperature. The dyes in TBE or a similar electrophoresis buffer can also be heated in the microwave oven, making them compatible with the common procedure used in making precast gels.
Furthermore, precast gels made with the dyes can be produced in bulk and stored for later use. Figure 2. Flexibility: many researchers like the option to choose between precast gel staining and post gel staining. For this reason, biosafety training is offered to anyone involved with activities at the labs that include use, handling, storage or disposal of this compound.
However, more investigations are needed to clear the real carcinogenic, mutagenic and teratogenic potencies of EtBr and its degraded molecules. We recommend that if there is no choice to use better alternatives instead, do not dilute large quantities of old stocks of EtBr and not dispose into the sink [ 8 ]. Charcoal filtration over chemical deactivation is strongly recommended.
Deactivation can be confirmed by use of UV light that detects the fluorescence. There are three recognized methods for deactivation: Armour, Lunn and Sansone, and finally Quillardet and Hoffnung methods [ 12 ]. Finding more efficient treating methods and also better disposal ways are really recommended to the researchers who involved in labs using this compound. Unfortunately, in some cities, some scientific schools and research centers have been established in the city centers where there is no good management of waste material.
Therefore, EtBr waste can enter into underground waters that might be used in garden, agriculture, washing or even drinking purposes.
Therefore, if the way of the waste material is tracked it would not be surprising to find a link with higher rate of some human cancers. However, there are still concerns on the toxicity and safety of the compounds which are used alternative to EtBr. Both authors contributed equally to the paper. Both authors read and approved the final manuscript. National Center for Biotechnology Information , U.
Journal List Daru v. Published online Dec Soodabeh Saeidnia 1, 2 and Mohammad Abdollahi 3. Author information Article notes Copyright and License information Disclaimer.
Corresponding author. Soodabeh Saeidnia: ri. SMUT dammahoM. If swallowed or inhaled: In the case of ingestion obtain medical attention immediately. If EtBr dust is inhaled move to a source of fresh air. Spills: All labs should have a Spill Kit available and anyone who uses it must first be trained. Spills of ethidium bromide solutions should be absorbed and the area decontaminated with soap and water. Avoid raising dust when cleaning up solid spills by mixing with water and then absorbing the solution.
All spill cleanup materials and absorbents should be bagged or placed in a sealed container with a hazardous waste label. Some facilities use a handheld UV lamp to check for residual ethidium bromide contamination following spill cleanup. A reddish-orange fluorescence can be detected under both "long" and "short" UV wavelengths. Users of the handheld lamps should be aware that their ability to detect small spills is not guaranteed. The ease of detection depends upon a variety of factors including the chemical composition of the sample, the wavelength of the UV lamp, and the intensity of the lamp.
Use of a handheld UV lamp to detect traces of ethidium bromide may serve as an occasional check of laboratory practices, but it cannot substitute for good cleanliness and careful contamination control.
Last modified: April 15, Learn how your comment data is processed. Facebook Twitter LinkedIn More. Written by Dr Nick Oswald. Log in to Reply. Ariwa99 on May 16, at pm. Dr Amanda Welch on May 21, at pm.
But the EtBr from my grad school lab was at least a decade old. Sudharsan on June 23, at pm. Leave a Comment Cancel Reply You must be logged in to post a comment.
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