In bacteria there are two main types of DNA—genomic and plasmid. Plasmid DNA is unique to bacteria. Eukaryotic cells don't typically have plasmid DNA unless it was put there by transfection for experimental purposes. The most important goal when isolating nucleic acids is to obtain the highest purity genetic material possible. When isolating genomic DNA it is important to remove plasmid DNA and RNA from the sample. Similarly, sometimes an experiment calls for the isolation of plasmid DNA, and the selective removal of genomic DNA is necessary. Also, some commercial RNA isolation kits include gDNA eliminator spin columns to remove genomic DNA from the isolate.
Traditional immunoassays such as the enzyme-linked immunosorbent assay (ELISA) are able to measure the presence or absence of only one analyte per reaction. Multiplex immunoassays measure dozens of different analytes in a single reaction. This is particularly beneficial for precious samples, and when only a small volume is collected for analysis. The multiplex immunoassay also saves working time since multiple assays can be completed simultaneously.
The ability to isolate and identify proteins from a biological solution is fundamental to basic research and clinical diagnosis. Proteins are the workhorses of the organism; they send and receive messages, they control the flow of information across the cell membrane, and they enact cascades of action within cells. It is rare that a single protein works alone, so it is imperative to understand how proteins interact with each other if we are to understand the nature of our bodies and to discover and treat disease.
Enzymes are used in the food, agricultural, cosmetic, and pharmaceutical industries to control and speed up reactions in order to quickly and accurately obtain a valuable final product. Enzymes are crucial to making cheese, brewing beer, baking bread, extracting fruit juice, tanning leather, and much more. The industrial uses of enzymes are also increasing since they are being used in the production of biofuels and biopolymers. The enzymes can be harvested from microbial sources or can be made synthetically. Yeast and E. coli are commonly engineered to overexpress an enzyme of interest. This type of enzyme engineering is a powerful way to obtain large amounts of enzyme for biocatalysis in order to replace traditional chemical processes.
Nano gold is another name for gold nanoparticles. These nanoparticles are a fraction of the size of human hair and are less than 100 nm in diameter. Nano gold particles are so small that it they are generally found as a colloidal solution, which means that the gold nanoparticles are suspended in a liquid buffer. Therefore, nano gold, or gold nanoparticles are also called colloidal gold. Also, nano gold is generally found in a colloidal solution because gold nanoparticles are created by citrate synthesis. This process involves mixing solutions together to result in the precipitation of gold nanoparticles into solution.
Magnetic properties of nanoparticles are used for drug delivery, therapeutic treatment, contrast agents for MRI imaging, bioseparation, and in-vitro diagnostics. These nanometer-sized particles are superparamagnetic, a property resulting from their tiny size—only a few nanometers—a fraction of the width of a human hair (nanoparticles are approximately 1/1,000 thinner than human hair). Superparamagnetic nanoparticles are not magnetic when located in a zero magnetic field, but they quickly become magnetized when an external magnetic field is applied. When returned to a zero magnetic field they quickly revert to a non-magnetized state. Superparamagnatism is one of the most important properties of nanoparticles used for biomagnetic separation.
Magnetic beads and separators have grown in popularity as a biotechnological tool over the past few decades. As we gained experience with the technology, we learned that all magnetic separators are not created equal. It turns out that it isn’t just the magnitude of the magnetic force that improves separation time, it is the way it spreads out over the working area that matters the most. A homogeneous magnetic separator is designed to ensure that every point within the working volume experiences the same magnetic force. This is especially important when scaling up a biomagnetic separation process from milliliters to liters.
The collection of tissue is a fundamental procedure for research and clinical biology. Before collection it is important to consider which method will be used to preserve the tissue and prepare it for histology or molecular analysis. There are two options to choose from when collecting and preserving tissue: frozen or formalin-fixed paraffin-embedded (ffpe). Each has its strengths and weaknesses, but these are only apparent when the intended use of the tissue is considered.
Anti human IgG is the most prevalent antibody isotype in human serum. It plays a critical role in the adaptive immune response. When a pathogen invades a human body it is intercepted by a white blood cell called a B-cell. These B-cell lymphocytes have cell surface receptors that bind a wide array of pathogens. Once activated, the B cell divides and produces offspring cells which secrete very specific antibodies capable of identifying that exact invading pathogen. These antibodies recognize a specific antigen binding site.
Protein A beads like ELISA, Immunoprecipitation, antibody purification, and multiplex assays require the attachment of specific antibodies to a solid support such as a column, polystyrene plate, agarose bead, or superparamagnetic nanoparticle. There are a number of ways that antibodies are attached to solid supports. Some of these include:
- covalently bonding the antibody’s primary amines directly to the surface
- biotin-streptavidin affinity linkages
- protein A and G
