DNA Purification

At the heart of molecular biology is the genetic starting material. DNA purification is therefore a critical procedure that can define the outcome and success of downstream molecular experiments. In most cases, before any researcher can begin a PCR reaction, clone a gene, or construct a sequencing library, DNA must first be extracted from the relevant sample and purified. In addition, the purification step should ideally be efficient and effective. The desired result is a high yield of DNA that is also free of contaminating particles, such as debris, protein, and RNA. Traditional DNA extraction methods, such as phenol-chloroform extraction, can be time-consuming and subject to user variability. In contrast, DNA purification kits contain quality-controlled components along with a standardized protocol to help ensure high-quality and reproducible yields. In this catalog, we present a comprehensive catalog of DNA purification tools.

What are the DNA types that can be purified?

DNA can be categorized based on physical characteristics, cellular location, or source of extraction. Here are some examples of common DNA types that are purified for downstream use:

• Genomic DNA - Genomic DNA, or gDNA, is the entire chromosomal genetic material of a given cell, tissue, or organism. gDNA isolation is an important initial step for collecting material for many molecular biology applications such as library construction and sequencing.
• Plasmid DNA - Plasmid DNA, stored and propagated in competent bacterial strains, are essential in molecular cloning and gene expression. Many plasmid purification methods take advantage of their small and circular physical characteristics.
• Tissue DNA - In contrast to bacterial cells, eukaryotic cells and tissues are structurally more complex. Some tissue samples, like blood and fixed tissue, can pose technical challenges for DNA extraction.
• Mitochondrial DNA - The isolation of mitochondrial DNA (mtDNA or mDNA) is an important first step for molecular investigations into the mitochondrial genome and its gene expression.
• Cell-free DNA - Cell-free DNA (cfDNA) are fragments of extracellular DNA that freely circulate in the bloodstream. The isolation and identification of cfDNA is important in biomarker discovery and cancer research.
• PCR products - DNA fragments resulting from PCR amplification are known as PCR products. Prior to downstream applications, these DNA can be purified from the PCR reaction mixtures or agarose gels after electrophoresis.

How do DNA purification kits work?

Generally, DNA extraction kits are designed to be straightforward, ready-to-use, and accommodating of multiple samples. Thus, kits will contain prepared liquid reagents such as lysis and elution buffers, stabilization reagents, and resin suspensions, as well as any disposable plasticware. A detailed protocol will instruct the user with step-by-step instructions, with mention of any required instrumentation. Some kits offer varying options in terms of purification scale. For example, miniprep kits can accommodate smaller amounts of starting material and DNA yields, while maxi and gigaprep kits, which may contain larger reagent volumes or container vessels, are ideal for larger-scale extractions. Many kits use chemical-based cellular lysis and separation, followed by binding of DNA to solid supports like membranes and resins. Elution is facilitated using gravity or centrifugal spin columns. Magnetic bead-based purification kits are also available, and are ideal for higher-throughput worfklows.

Biocompare lists a comprehensive catalog of DNA purification kits and reagents from many trusted suppliers. Explore the product categories that are relevant to your research needs and discover new kits to aid in your DNA extraction procedures.