Stability of magnetic bead IVD kits over time is important and should reflect the environment that is typically encountered by their reagents. For example, if the reagents will be frozen and thawed, stability should be addressed in these conditions. Magnetic beads, such as streptavidin beads, may behave heterogeneusly in different conditions, so these should be preserved when performing stability studies.
Although there are many choices you can make when determining bead surfaces, there are five predominant types of magnetic beads currently used most often by Chemiluminescent Immunoassay (CLIA) companies.
Chemiluminescent immunoassays (CLIAs) are excellent assays for high-throughput, low analyte concentration and time sensitive testing and isolation. Using coated magnetic beads, such as streptavidin beads, as the reagent in a CLIA is an easy and established technique favored among many clinical scientists.
Depending on your antibody and your assay, you have a number of ways to couple your protein or antibody to the surface of your magnetic beads. Once again, forethought is important in choosing which bead surface to use. Plain surfaces, modified surfaces or pre-activated surfaces in streptavidin beads are examples of these possible choices.
When determining which magnetic microsphere to use for your CLIA, it is important to take into consideration a variety of different variables. Magnetic streptavidin beads are a well-known example of these magnetic microspheres, but there are many alternatives we must take into account.
In Chemiluminescent immunoassays, antibodies are bound to the used magnetic beads (such as streptavidin beads) in order to detect a certain analyte. However, there are different types of antibodies that behave in different ways and recognize a variety of epitopes.
When developing and using a CLIA, it is important to follow eight basic steps in order to ensure that your assay will be the most efficient and accurate that it can be. Whether we are using magnetic streptavidin beads or another type of beads, these are the steps we must follow.
Well-established classical detection methods that are packed in kit form include Radioimmunoassays (RIAs) or Enzyme Linked Immunoassays (ELISAs). These two detection methods were highly sensitive and used for a variety of biological and chemical testing. Even though RIAs are very sensitive assays, by their very nature, they are comprised of highly hazardous, radioactive reagents. The handling and disposal of RIA refuse can be difficult to regulate in the lab environment as well as expensive.
Retrieving analytes from their original sources (especially when working on proteins) can be tricky and difficult. In addition, various methods of analyte recovery are highly concentration dependent. For example, analytes can be extracted from very concentrated samples, e.g. greater than or equal to 1 mg/ml, with methods such as nephelometry or turbidmetry. Lower concentrations such as 1 ug/ml require the use of an ELISA or Immunofluorescence assays to isolate the desired analyte.