The enzyme-linked immunosorbent assay (ELISA) is a commonly used analytical biochemistry assay, first described by Engvall and Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presence of a ligand in a liquid sample using antibodies directed against the protein to be measured. ELISA has been used as a diagnostic tool in medicine, plant pathology, and biotechnology, as well as a quality control check in various industries.
Chemiluminescence is the emission of light (luminescence) as the result of a chemical reaction. There may also be limited emission of heat. Given reactants A and B, with an excited intermediate ◊,
Luciferase is a generic term for the class of oxidative enzymes that produce bioluminescence, and is usually distinguished from a photoprotein. The name was first used by Raphaël Dubois who invented the words luciferin and luciferase, for the substrate and enzyme, respectively. Both words are derived from the Latin word lucifer, meaning "lightbearer", which in turn is derived from the Latin words for "light" (lux) and "to bring or carry" (ferre).
Affymetrix is a brand of DNA microarray products sold by Thermo Fisher Scientific that originated with an American biotechnology research and development and manufacturing company of the same name. The Santa Clara, California-based Affymetrix, Inc. was founded by Stephen Fodor and his group, based on their earlier development of methods to fabricate DNA microarrays using semiconductor manufacturing techniques.
The Bradford protein assay was developed by Marion M. Bradford in 1976. It is a quick and accurate spectroscopic analytical procedure used to measure the concentration of protein in a solution. The reaction is dependent on the amino acid composition of the measured proteins.
RiboGreen is a proprietary fluorescent dye that is used in the detection and quantification of nucleic acids, including both RNA and DNA. It is synthesized and marketed by Molecular Probes/Invitrogen of Eugene, Oregon, United States. In its free form, RiboGreen exhibits little fluorescence and possesses a negligible absorbance signature. When bound to nucleic acids, the dye fluoresces with an intensity that, according to the manufacturer, is several orders of magnitude greater than the unbound form. The fluorescence can be detected by a sensor and the nucleic acid can be quantified. The presence of protein contaminants in the sample of nucleic acids to be tested does not make significant contributions to the absorbance, and thus allows for the addition of deoxyribonucleases to the protocol in order to degrade DNA, in the instances where one is only interested in detecting or quantifying RNA.
Chemical biology is a scientific discipline spanning the fields of chemistry and biology. The discipline involves the application of chemical techniques, analysis, and often small molecules produced through synthetic chemistry, to the study and manipulation of biological systems. In contrast to biochemistry, which involves the study of the chemistry of biomolecules and regulation of biochemical pathways within and between cells, chemical biology deals with chemistry applied to biology.
Fisher Scientific International, Inc. was a laboratory supply and biotechnology company that provided products and services to the global scientific research and clinical laboratory markets until its merger with Thermo Electron in 2006, after which it became Thermo Fisher Scientific. The company offered products and services to over 350,000 customers located in approximately 150 countries including pharmaceutical and biotechnology companies, secondary and higher education institutions, hospitals and medical research institutions, and quality control, process control and research and development laboratories.
Invitrogen is one of several brands under the Thermo Fisher Scientific corporation. The product line includes various subbrands of biotechnology products, such as machines and consumables for polymerase chain reaction, reverse transcription, cloning, culturing, stem cell production, cell therapy, regenerative medicine, immunotherapy, transfection, DNA/RNA purification, diagnostic tests, antibodies, and immunoassays.
The Alexa Fluor family of fluorescent dyes is a series of dyes invented by Molecular Probes, now a part of Thermo Fisher Scientific, and sold under the Invitrogen brand name. Alexa Fluor dyes are frequently used as cell and tissue labels in fluorescence microscopy and cell biology. Alexa Fluor dyes can be conjugated directly to primary antibodies or to secondary antibodies to amplify signal and sensitivity or other biomolecules.
MilliporeSigma is an American chemical, life science and biotechnology company, before 2014 known as Sigma-Aldrich, owned by Merck KGaA.
The bicinchoninic acid assay, also known as the Smith assay, after its inventor, Paul K. Smith at the Pierce Chemical Company, now part of Thermo Fisher Scientific, is a biochemical assay for determining the total concentration of protein in a solution, similar to Lowry protein assay, Bradford protein assay or biuret reagent. The total protein concentration is exhibited by a color change of the sample solution from green to purple in proportion to protein concentration, which can then be measured using colorimetric techniques.
The biurettest, also known as Piotrowski's test, is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper(II) ion forms mauve-colored coordination complexes in an alkaline solution. Several variants on the test have been developed, such as the BCA test and the Modified Lowry test.
The enzyme horseradish peroxidase (HRP), found in the roots of horseradish, is used extensively in biochemistry applications. It is a metalloenzyme with many isoforms, of which the most studied type is C. It catalyzes the oxidation of various organic substrates by hydrogen peroxide.
Thermo Fisher Scientific is an American provisioner of scientific instrumentation, reagents and consumables, and software services. Based in Waltham, Massachusetts, Thermo Fisher was formed through the merger of Thermo Electron and Fisher Scientific in 2006. Thermo Fisher has acquired other reagent, consumable, instrumentation, and service providers, including: Life Technologies Corporation (2013), Alfa Aesar (2015), Affymetrix (2016), FEI Company (2017), & BD (2018).
The DyLight Fluor family of fluorescent dyes are produced by Dyomics in collaboration with Thermo Fisher Scientific. DyLight dyes are typically used in biotechnology and research applications as biomolecule, cell and tissue labels for fluorescence microscopy, cell biology or molecular biology.
Fermentas was a biotechnology company specializing in the discovery and production of molecular biology products for life science research and diagnostics. Since 2010, Fermentas has been part of Thermo Fisher Scientific.
Dharmacon Inc., now known as Dharmacon, was founded in 1995 by Stephen Scaringe as Dharmacon Research to develop and commercialize a new technology for RNA oligonucleotide synthesis. Originally, the company's focus was to develop 2'-ACE RNA technology as the standard for RNA synthesis and to advance RNA oligo-dependent applications and technologies.
Bioreporters are intact, living microbial cells that have been genetically engineered to produce a measurable signal in response to a specific chemical or physical agent in their environment. Bioreporters contain two essential genetic elements, a promoter gene and a reporter gene. The promoter gene is turned on (transcribed) when the target agent is present in the cell’s environment. The promoter gene in a normal bacterial cell is linked to other genes that are then likewise transcribed and then translated into proteins that help the cell in either combating or adapting to the agent to which it has been exposed. In the case of a bioreporter, these genes, or portions thereof, have been removed and replaced with a reporter gene. Consequently, turning on the promoter gene now causes the reporter gene to be turned on. Activation of the reporter gene leads to production of reporter proteins that ultimately generate some type of a detectable signal. Therefore, the presence of a signal indicates that the bioreporter has sensed a particular target agent in its environment.
Virus quantification involves counting the number of viruses in a specific volume to determine the virus concentration. It is utilized in both research and development (R&D) in commercial and academic laboratories as well as production situations where the quantity of virus at various steps is an important variable. For example, the production of viral vaccines, recombinant proteins using viral vectors and viral antigens all require virus quantification to continually adapt and monitor the process in order to optimize production yields and respond to ever changing demands and applications. Examples of specific instances where known viruses need to be quantified include clone screening, multiplicity of infection (MOI) optimization and adaptation of methods to cell culture. This page discusses various techniques currently used to quantify viruses in liquid samples. These methods are separated into two categories, traditional vs. modern methods. Traditional methods are industry-standard methods that have been used for decades but are generally slow and labor-intensive. Modern methods are relatively new commercially available products and kits that greatly reduce quantification time. This is not meant to be an exhaustive review of all potential methods, but rather a representative cross-section of traditional methods and new, commercially available methods. While other published methods may exist for virus quantification, non-commercial methods are not discussed here.
