Precautions for laboratory elisa plate
According to different classification standards, ELISA plates have different classifications.
1. According to the number of wells, it can be divided into 96 wells and 48 wells, of which 96 wells are the most commonly used now, because the elisa microplate is used with the microplate reader. The elisa 96 well plate is also required when purchasing, and the manufacturer basically made a 96-well plate in order to adapt to the market.
2. According to the difference of the bottom, it is divided into flat bottom, U-shaped bottom and V-shaped bottom. The refractive index of the flat bottom is low, which is suitable for detection in the microplate reader; the refractive index of the microplate plate with the U-shaped bottom is higher, which is convenient for operations such as adding, aspirating, and mixing. Observe the color changes to determine whether there is a corresponding immune response. The V-bottomed microtiter plate can accurately aspirate samples.
1) High binding force
After the surface of this ELISA plate is treated, its protein binding ability is greatly enhanced, reaching 300~400ng IgG/cm2, and the molecular weight of the main binding protein is more than 10kD. The use of this type of ELISA plate can improve the sensitivity, and can relatively reduce the concentration and dosage of the coated protein, but the disadvantage is that it is easy to produce non-specific reactions. After antigen or antibody coating, non-ionic detergents cannot effectively block unbound protein sites, so protein should be used as a blocking agent.
2) Medium binding force
This type of ELISA plate is passively bound to proteins through surface hydrophobic bonds, and is suitable as a solid-phase carrier for macromolecular proteins with a molecular weight of >20kD, and its protein binding capacity is 200~300ng IgG/cm2. Due to the characteristics of this type of ELISA plate that only binds to macromolecules, it is suitable for use as a solid-phase carrier for unpurified antibodies or antigens, which can reduce potential non-specific cross-reactions. These plates can be blocked with inert proteins or non-ionic detergents.
3) Amination
This ELISA plate has positively charged amino groups after surface modification, and its hydrophobic bonds are replaced by hydrophilic bonds. This type of ELISA plate is suitable as a solid-phase carrier for small molecular proteins. Using the appropriate buffer and pH, its surface can bind negatively charged small molecules via ionic bonds. Due to the hydrophilic nature of its surface and its ability to be covalently bound by other cross-linking agents, it can be used to immobilize protein molecules dissolved in detergents such as Triton-100 and Tween 20. The disadvantage of this type of plate is that some protein molecules cannot bind due to the reduced hydrophobicity; in addition, the surface needs to be effectively blocked. Due to the hydrophilic and covalent surface properties, the blocking solution used must be able to interact with non-reactive amino groups and any functional groups in the chosen crosslinker.
Fourth, according to the color is divided into transparent, black, white.
Transparent is the most commonly used and used for the most general ELISA experiments. Compared with the transparent board, there are also opaque boards for luminescence detection, generally black and white. The black ELISA plate itself will absorb light, so its signal is much lower than that of the white plate, so it is generally used to detect strong light, such as fluorescence detection. The white ELISA plate is used for weak light detection and is often used for general chemiluminescence. In addition, the black microtiter plate can also reduce the problems caused by non-specific reactions. Some customers will ask whether it is possible to perform luminescence detection with a general ELISA plate, and the answer is no, because the light emitted from the chemiluminescence reaction is generally isotropic, that is to say, it is emitted equally in all directions. . If a transparent board is used, the light will radiate not only from the vertical direction, but also from the horizontal direction. It is easy to pass through the gaps between the various holes and the hole walls. In this case, when the light is strong, the influence between adjacent wells will be great, so the chemiluminescence experiment cannot be performed with a transparent ELISA plate.
5. Most of the elisa strip well plates that everyone sees now can be disassembled, that is, a single strip can be disassembled, and there are also fixed plates. A single detachable plate can actually save a lot of money, because then when you want to use a new ELISA plate, you can remove the ELISA strip and buy some ELISA strips, just consider To match the same model can be. In addition, detachable 96 well elisa strip plates can be used for in vitro testing, which is easy to remove.
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