What is chelex® 100?
Introduced in 1991 to the forensic DNA community, Chelex® 100 (Bio-Rad Laboratories, Hercules, CA) is an ion-exchange resin that is added as a suspension to the samples (Walsh et al. 1991).
What is Chelex chelating ion exchange resin?
Chelex chelating ion exchange resin has unusuallyhigh preference for copper, iron, and other heavy met-als over monovalent cations such as sodium andpotassium. Its selectivity for divalent over monovalentions is approximately 5,000 to 1, and it has a verystrong attraction for transition metals, even in highlyconcentrated salt solution.
What is the best way to make a Chelex solution?
The most effective way to do this is to take a 50 ml sterile falcon tube, place in on a scale inside a small beaker and zero the scale. Then add 5 grams of Chelex and fill to 50ml mark with water.
What are the advantages of Chelex extraction over PCR extraction?
However, Chelex extraction is an advantage for PCR-based typing methods because it removes inhibitors of PCR and uses only a single tube for the DNA extraction, which reduces the potential for laboratory-induced contamination.
How does Chelex DNA extraction work?
Principle: Chelex resin works by preventing DNA degradation from degradative enzymes (DNases) and from potential contaminants that might inhibit downstream analyses. In general, the Chelex resin will trap such contaminants, leaving DNA in solution.
How does Chelex protect DNA during DNA extraction?
Resin beads bind to the cellular components, while DNA (and RNA) remains dissolved in the aqueous solution. Chelex resin also inhibits DNA degradation by chelating metal ions. This method is particularly beneficial for forensic applications, but it is not appropriate for large-scale DNA extraction.
What is Chelex and why is it used?
Chelex 100 Resin is a styrene divinylbenzene copolymer containing paired iminodiacetate ions, which act as chelating groups in binding polyvalent metal ions. It can be used for fast and easy DNA and RNA preparations.
What does Chelex do in the protocol?
The Chelex method has been used with amplification and typing at the HLA DQα locus to obtain the DQα genotypes of many different types of samples, including whole blood, bloodstains, seminal stains, buccal swabs, hair and post-coital samples.
Does Chelex lyse cells?
Chelex is a chelating ion-exchange resin that binds polar components of cells leading to cell lysis.
Does Chelex inhibit PCR?
Further, we have demonstrated that extracting DNA from blood samples using the older Chelex-based protocol is inconsistent and occasionally inhibits the PCR reaction.
What is Chelex made of?
Chelex 100 Resin is made of a styrene divinylbenzene copolymer containing paired iminodiacetate ions, which act as chelating groups in binding polyvalent metal ions.
How do you make a 5% Chelex?
Prepare a 5-10% by weight slurry of Chelex100 Resin (Biorad part 143- 3832,100-200 mesh Chelex, sodium form) and UV sterilized HPLC water. The most effective way to do this is to take a 50 ml sterile falcon tube, place in on a scale inside a small beaker and zero the scale.
How do you extract DNA from an FTA paper?
The basic premise of purifying DNA using FTA® paper is simple: biological samples are applied to the FTA® paper and air-dried. A small disc of the FTA® paper is then removed, and washed to remove any non-DNA material (the DNA remains entangled within the paper).
Can you autoclave Chelex?
Autoclave. Store at 2° to 8°C.
What is Chelex made of?
Chelex 100 Resin is made of a styrene divinylbenzene copolymer containing paired iminodiacetate ions, which act as chelating groups in binding polyvalent metal ions.
Why is heat used in DNA extraction?
Heating helps to denature proteins, extract DNA from spots, increase speed of chemical reactions, inactivate enzymatical reactions inhibitors etc. Heating is not an alternative method of DNA precipitation. Heating will always eliminate nucleases and increase DNA yield .
How do you extract DNA from an FTA paper?
The basic premise of purifying DNA using FTA® paper is simple: biological samples are applied to the FTA® paper and air-dried. A small disc of the FTA® paper is then removed, and washed to remove any non-DNA material (the DNA remains entangled within the paper).
How is DNA extracted from dried blood?
Place punches in 1 ml 0.5% saponin.Incubate at 4°C overnight.Remove saponin and add 1 ml PBS.Incubate at 4°C for 30 min.Remove PBS and place punches in 100 µl 5% Chelex-100.Incubate at 100°C for 8 min.Centrifuge at 10 600 g for 2 min.Carefully remove and store supernatant at −20°C if the extract is not used promptly.
What is Chelex 100 used for?
Chelex 100 resin has found many uses. Theseinclude analysis of trace metals in natural waters,reagents, biochemical, and physiological fluids;removal of trace metals from reagents, biochemicals,physiological fluids, culture media, soils, and enzymesystems; recovery of metals from process streams; andchromatography of closely related metals.
How long is chelex resin stable?
Chelex resin is stable for at least 2 years whenstored sealed in the original container at 22 °C. It shouldbe stored in a salt form such as sodium or ammonium. Ifleft in the hydrogen form for more than a few hours, theresin has a tendency to lose chelating capacity. Shouldsuch a loss occur, the resin can be regenerated by heat-ing it at 60 °C in 30-50% alkali for 24 hours. Free imin-odiacetic acid produced upon long standing (detected byits odor) may be extracted by methanol or by heating to
What is the selectivity of chelating ion exchange resin?
Its selectivity for divalent over monovalentions is approximately 5,000 to 1, and it has a verystrong attraction for transition metals, even in highlyconcentrated salt solution.
Can you remove metals from chelating resin?
Metals can be removed with Chelex chelatingresin using either the batch or the column technique ,though the column technique is generally more effi-cient. The most effective agents to elute the metalsfrom the resin are acids. Concentrated salt solutionsare often useful for selective elution, but are generallyinefficient in removing strongly absorbed metals.
