The separation matrixes of nucleic acid electrophoresis include agar, agarose, polyacrylamide, and composite agarose-acrylamide gels. Among them, agarose and polyacrylamide are the two most used gels in nucleic acid electrophoresis. Polyacrylamide gels are suitable for separating nucleic acid molecules smaller than 1000 bp. More porous agarose gels can be used to separate mixtures of larger fragments up to 20kb.
The concentration of the gel determines the pore size of the gel which affects the migration of nucleic acids. The resolution of nucleic acids varies with the percentage concentration of the gel. Increasing the agarose concentration of the gel reduces the migration rate and improves the separation of smaller nucleic acid molecules, while decreasing the concentration of the gel allows the separation of larger nucleic acid molecules.
For agarose gel electrophoresis, 0.7% gel shows good separation or resolution for 5-10 kb DNA fragments, while 2% gel shows good resolution for 0.2-1 kb DNA fragments. Up to 3% can be used to separate very tiny fragments, but high concentration gels require longer running time and are tend to bebrittle and may not set uniformly.
Amerigo Scientific offers agarose powders and convenient tablets for size-based separation of nucleic acids in electrophoresis application.
|Agarose Tablets (DNase/RNase free)||0.5g x 110 Tablets|
|Agarose Powder (Molecular Biology Grade)||100 g|
|Agarose Powder (Molecular Biology Grade)||500 g|
To streamline the workflow and save time, convenient agarose tablets are supplied.
Nucleic acid fragment size is usually reported in "nucleotides", "base pairs (bp)" or "kb” depending upon whether single- or double-stranded nucleic acid has been separated. Fragment size is usually determined by comparison with nucleic acid standards that contain fragments of known length.
The easiest way to see the results of a gel electrophoresis experiment is to stain the gel with a nucleic acid stain. Ethidium bromide (EtBr) is a common stain in agarose and polyacrylamide gels. EtBr binds to DNA molecules by intercalating between adjacent base pairs and emits an intense red-orange fluorescence under UV light.