Competent cells are cells capable of taking up and integrating foreign DNA from its surrounding environment. This process of genetic uptake is called transformation. In eukaryotic cells, horizontal gene transfer is more difficult than in prokaryotic cells because the genetic material must pass through the cell membrane and the nuclear membrane. Although a cell may be considered naturally competent, this competent state is not necessarily constant. The DNA taken up by a naturally competent cell does not always integrate into the cell's genome.
Artificially induced competent cells can be produced through electrical (electroporation) or chemical treatments. Competent cells have become an important tool in cloning research because they provide a method for introducing new genetic material into cells. Whether in electroporation or chemical treatment method, competent cells are produced by creating temporary pores on the cell membrane so that DNA can pass through. Chemically competent cells are prepared by salt treatment and heat shock procedures. The method for preparing electroporation competent cells involves using an electric pulse to disrupt the cell membrane, causing a slight rearrangement of the lipid bilayer, thereby allowing exogenous gene to enter the cell.
Chemically competent cells are a popular choice for many standard molecular biology applications, because both the cost of preparing chemically competent cells in the laboratory and commercially available options are lower than that of electroporation competent cells. Preparing chemically competent cells does not require special equipment, and the method is robust and has low sensitivity. Chemically competent cells are suitable for routine cloning, such as standard plasmid cloning and subcloning. However, compared to electrocompetent cells, the transformation efficiency of chemically competent cells is lower, typically ranging from 10⁶ to 10⁸ colony-forming units (CFU) per microgram of DNA. Electrocompetent cells can achieve extremely high transformation efficiencies of 10⁹ to 10¹⁰ CFU per microgram of DNA and are ideal for challenging applications, such as constructing DNA libraries (cDNA or genomic), cloning rare DNA fragments, and transforming very large plasmids or bacterial artificial chromosomes (BACs). Due to their high efficiency, transformation can be achieved even with a very small amount of DNA. In addition, the electroporation method can be used to transform a wide range of bacteria, including those that are difficult to chemically transform.
Amerigo Scientific offers high-quality and cost-effective chemically competent cells for routine molecular cloning and subcloning. We also provide electrocompetent cells with high transformation efficiencies, which are suitable for challenging cloning applications. The selection of competent cells should be based on considerations of efficiency, cost, and the specific demands of the research.
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