Microplate Selection For Optimization Of Assays
By Liisa Vexler
Many different kinds of microplates are available nowadays, and these are suitable for different types of research and diagnostic modalities, and it is important that a correct microplate be optimized to get accurate results as the optimization of reagents to be used in the assay. These microplates can be customized to get maximum optimization for parameters as chemical resistance, cell adhesion and compatibility with optic measurements. The appropriate selection of the plate is made upon the type of reader’s absorbance sensitivity for fluorescence or chemiluminescence for different diagnostic tools like ELISA and simple 96-well microplates and the sensitivity of the substances being measured as hormones, antibodies and viral proteins.
To get accurate results that are reproducible, several things need to be considered while selecting the plate. For instance, the type of molecule being measured, storage capacity of the plate, the interaction between molecules and plate surface material as in the case of ELISA, where the molecular sample needs to be immobilized on the plate, which can be a very laborious process, and accuracy of the result depends on this molecular and plate material interaction. One of the challenging examples is creating a lipid bilayer membrane on the plate surface to measure ionic exchange, and it requires precision in every aspect as knowledge of surface chemistry. There are three major types of surfaces used for the biomolecule attachment namely passive adsorption surface, covalent binding surface and affinity capture surface. Passive adsorption plate has a very wide range of capacity to bind different kinds of molecules and make very stable bonds with the molecules. It can be further classified very hydrophilic plates, standard hydrophilic plates, slightly hydrophilic plates and hydrophobic plates. All these have different applications for different assay types and molecular types. Covalent binding plates are used for larger molecules like peptides, and it binds the molecule with single covalent bond with its functional group. The affinity capture surface plate uses receptor molecules immobilized on its surface to bind the specific molecules using molecular-receptor affinity.
In summary, choosing the right type of microplate with specific surface type and characteristic is imperative in assay optimization to get precise and accurate results and reproducibility of the assay at diagnostic and research level.