Size exclusion chromatography columns are used to separate molecules by size, molecular weight, and hydrodynamic volume. The technique can be used with proteins, polymers, and other macromolecules. It can also be used for buffer exchange or desalting a sample. The principle behind size exclusion chromatography columns is simple, but the technique only works when the correct resin-bound column is matched to the experimental goal.
From the clinical laboratory ELISA to the home pregnancy test, the conjugated antibody is integral to the function of many diagnostic assays. We know about the specificity of antigen-antibody interactions and their role in mounting the innate immune response to a pathogen. This antigen recognition specificity has been utilized by clever scientists and engineers to create biosensors capable of detecting the presence of antigens in biological samples. Biosensors come in many shapes and sizes, and have varying levels of complexity, but one fundamental concept is the need to covalently attach antibodies to a substrate.
The binding specificity between antibody and antigen drive our immune systems to successfully fight infection. When a viruses or bacteria invade a body they are engulfed by macrophages, which break them down and present their epitopes to the B cells lymphocytes. These B cells read the epitope and create antibodies with an antigen binding site, or paratope, that specifically recognizes the invading pathogen, binds to it, and signals to the rest of the immune system that the pathogen/antigen should be destroyed. This antibody affinity to antigen is similar to the specificity of a key in a lock.
The business value of potentially large production capacities coupled to lower capital expenditures (CapEx) requirements and manufacturing costs may reduce the gap between production volumes and patient needs for potentially life-saving drugs. This is the reason because pharmaceutical companies are continuously seeking for new technologies. An economically efficient alternative to bioreactor-based technologies is the use of living biofactories such as transgenic animals, plants or insects.
A need for rapid, reproducible, small-scale purification
For many recombinant protein applications, such as expression clone screening and for optimizing expression conditions, there is a crucial need for a rapid, reproducible, small-scale purification process. Traditionally, protein purification from E. coli consists of four distinct phases: harvest, bacterial cell lysis, lysate clarification and protein purification. You will find the whole process explained step by step in our protein purification handbook.
The search for alternatives to chromatographic resins is not new. With the continuous increase in expression levels in recombinant protein purification, columns are struggling with crude lysates. The need to clarify suspensions containing high levels of expressed protein for post-purification re-concentration no longer appears to be the most efficient strategy. You will find much more information about this topic in our protein purification handbook.
Nanoparticles incorporating different functions are useful and necessary products for assays, drug delivery, and other life science applications. For example, magnetic nanoparticles can be used as contrast agents for magnetic resonance imaging (MRI), to dissipate energy under an oscillating field to locally raise temperature (hyperthermia), or to improve manufacturing of complex nanoparticles via use of magnetic separation. One or more different antibodies and/or fluorescence, luminescence agents as well as other functionalities such as catalytic or enzymatic groups can be attached to nanoparticles.
In order to ensure the success of a protocol, it is essential to have a clear and unbiased knowledge base and a reliable source of reference material. When trying to decide the best platform or application to use for a process, it is critical to ensure that the information on which the decision will be based is generic and factual, and not propagated as promotional data.
Magnetic beads have several advantages over alternate non-magnetic bead technologies, and are thus finding increasing application in all areas of life-sciences research and development including drug discovery, biomedicine, bioassay development, diagnostics, genomics and proteomics.
It is well known that most recombinant protein purifications are mainly done through different types of chromatography, explained in our protein purification handbook. However, the use of magnetic particles is a very interesting alternative to these techniques, providing great advantages and simplifying the process in many aspects. The necessary equipment for purification with magnetic particles is simple: we need a magnet or any device capable of creating a magnetic field, and the particles themselves.
