Thermo Scientific™ Immuno Clear Standard Modules

Assay sensitivity depends strongly on efficient removal of non-specific reacting molecules. High background readings and coating instability can be minimized by addition of a blocking step after the first coating. The excess surface is then occupied by indifferent molecules.
We recommend washing three times after each coating step by using a solution of 0.15 M phosphate buffer (pH 7.2) with 0.2 M NaCl and 0.05% Tween 20.
For blocking, we recommend using 0.5% BSA, 1% casein or 1% gelatin in 0.15 M phosphate buffer (pH 8.2) or carbonate buffer (pH 9.6).

The choice of plates or modules will depend on the type of RIA you are planning to perform and specific assay conditions. Nunc provides two different surfaces for immunoassays, PolySorp and MaxiSorp.
- MaxiSorp surface is highly charged and should be used if the assay requires quantitative measurement of proteins (antibodies) or molecules with polar groups.
- PolySorp surface should be used if the assay consists of less polar molecules with hydrophobic characteristics.

The following list offers a brief description of the features of Nunc products and their specific applications:
- Nunc-Immuno Plates, MaxiSorp surface - These plates are designed for solid phase immuno assays and have a polystyrene surface with high affinity for polar groups and hydrophilic molecules. These 96-well plates are available with flat (F), round (U), or (C) bottom-well designs.
- Nunc-Immuno Plates, PolySorp surface - These plates have a polystyrene surface which adsorps less polar molecules compared to the MaxiSorp surface and has a high affinity for hydrophobic groups. These 96-well plates are available with flat (F), round (U), or (C) bottom-well designs.
- Nunc-Immuno Modules - These modules are designed for solid-phase immuno assays. The modules are available in 8-, 12- or 16-well formats with (F), (U), and (C) bottom-well and 8-well BreakApart with (C) bottom-well designs. These different formats allow one to choose the style which is appropriate for their assay design.
BreakApart Modules and LockWell Modules can be used for radioimmunoassays.
- Nunc StarWell Immuno Breakable Modules - The 8-well modules feature eight fins on the inner wall of the (C) bottom wells. This design increases the surface area by 50%. The increase in surface area allows more molecules to be immobilized, increasing assay signal. The fin configuration provides shorter diffusion distance to the surface, reducing incubation times.
- LockWell Immuno Breakable Modules - Each plate consists of 1 x 8 breakable strips. These strips are assembled in a designed frame which locks each well into place by a spring lock. This spring lock design orientates each well at the same horizontal level allowing uniform washing and reading. The LockWell Modules are available with round (U), (C) or StarWell bottom-well designs.
- Plates and Modules with (CovaLink) Covalent Binding Surfaces: These plates can be used to bind proteins, peptides, DNA or carbohydrates. Covalent linkage occurs via secondary amine group. This allows a specific orientation and provides improved stability compared to passive adsorption due to chemical binding between molecules. Binding of molecules on PolySorp and MaxiSorp surfaces is obtained by passive adsorption. CovaLink is a surface grafted with secondary amino groups (<NH) which serves as a bridge for covalent coupling. The covalent binding can immobilize small molecules such as biotin or peptides which may otherwise bind weakly by physical adsorption and facilitate the recognition by detection molecule.
- Nunc FluoroNunc/LumiNunc 96-Well Plates: These plates are optimized for IFMA (Immunofluorometric Assays) or FIA (Fluorometric Immuno Assays). The transparent polystyrene plates give a low background fluorescence and are optimal where a read-through system is used. The white plates/modules provide maximum reflection of fluorescence signal while maintaining low background. The white plates/modules are often used for epifluorescence reading. Black modules reduce background fluorescence and minimize back-scatter light which is often encountered in epifluorescence.

Molecules bind to our PolySorp and MaxiSorp surfaces through passive adsorption.
Using IgG as a reference molecule and knowing that it is a globular molecule, theoretical calculations indicate that the maximum binding for proteins are:
- For the MaxiSorp surface, in monolayer: 650 ng/cm^2
- For the PolySorp surface: 220 ng/cm^2.

MaxiSorp, PolySorp and MiniSorp surfaces were developed for immunology assays:
- The MaxiSorp surface is a modified, highly charged polystyrene surface with high affinity for molecules with polar or hydrophilic groups. The surface has a high binding capacity for proteins, including globular antibodies in proper orientation. Thus, it offers very high sensitivity in double antibody "sandwich" tests.
- The PolySorp surface is more hydrophobic than the MaxiSorp surface. It has high affinity to molecules of a more hydrophobic character. This surface is particularly suited to non-protein antigens including virus antigens.
- The MiniSorp surface is a polyethylene surface with very low affinity to molecules of any type. This type of surface is ideal for the liquid phase immuno techniques.
- The MiniSorp surface is only available in a tube format, while the MaxiSorp and PolySorp surfaces are offered in both 96-well plate and module formats.

Our passive immunodiagnostic surfaces are based on a series of treatments that modify the polystyrene surface to different final levels of hydrophilicity. Selection of one of these surfaces for ELISA development should be based on the characteristics of the biomolecule you seek to immobilize. PolySorp is fairly hydrophobic and should be used for biomolecules that have hydrophobic domains, e.g., lipids, lipoproteins, and large proteins. MediSorp is slightly hydrophilic and can be used for biomolecules with hydrophilic and hydrophobic properties, e.g., medium-to-large proteins such as albumin, or amphiphilic biomolecules such as LPS. MaxiSorp is quite hydrophilic, optimized for binding of IgG (and any other molecule with similar characteristics) and thus is a popular choice for sandwich ELISA and similar protocols. MultiSorp is very hydrophilic, and in turn will immobilize very hydrophilic biomolecules such as glycoproteins. Some optimization will always be necessary, and in many cases screening for binding optimization may involve a few surface types.

There is no difference in the manufacturing process. Certified plates are performance tested (using an antibody binding protocol) during quality control, whereas uncertified plates are not. This test is expensive for us to perform, so we offer the uncertified version at cost savings customers for whom antibody binding testing results are not critical.