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Disadvantages of plasma donation

1. If the plasma donor has mild coagulopathy, he may induce bleeding symptoms after plasma donation. Symptoms include bleeding spots, bruises on the skin and mucous membranes, bleeding from the nose and gums, and even blood in the urine. Therefore, people with coagulation disorders cannot donate plasma. 2. After plasma donation, the immune function of the human body may be slightly decreased, and it may be susceptible to infection or other diseases. Therefore, people with weakened immunity should not donate plasma. In short, donating plasma will have a slight impact on the body's immune and coagulation function.

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Specific classification of ELISA plate

   According to different classification standards, the microplate has different classifications.

   1. According to the number of wells, it can be divided into 96 wells and 48 wells, among which 96 wells are the most commonly used now, because the microplate reader is used with microplate readers, and the most common microplate readers made by current microplate readers are 96 wells. So customers also want 96-well plates when they buy, and manufacturers basically make 96-well plates in order to adapt to the market.

   2. According to the different bottoms, it is divided into flat bottom, U-shaped bottom and V-shaped bottom. The flat bottom has a low refractive index and is suitable for detection in the microplate reader; the U-shaped bottom microplate has a higher refractive index, which is convenient for operations such as sample addition, aspiration, and mixing. It can be directly visualized without being placed on the microplate reader. Observe the color change to determine whether there is a corresponding immune response. The ELISA plate at the bottom of V can absorb samples.

   3. According to the different binding ability of the ELISA plate with proteins and other molecules, it is divided into high binding capacity, medium binding capacity and aminated ones.

   1) High binding force

   After the surface of this kind of ELISA plate is treated, its protein binding capacity is greatly enhanced, reaching 300~400ng IgG/cm2, and the main binding protein molecular weight is> 10kD. The use of this type of microtiter plate can improve the sensitivity, and can relatively reduce the concentration and dosage of the coating protein. The disadvantage is that it is easier to produce non-specific reactions. After the antigen or antibody is coated, non-ionic detergents cannot effectively seal the unbound protein sites, and protein should be used as a sealant.

   2) Middle binding power

   This type of ELISA plate passively binds to proteins via hydrophobic bonds on the surface, 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. Because this type of microtiter plate has the characteristic of only binding to macromolecules, it is suitable as a solid-phase carrier for unpurified antibodies or antigens, and can reduce potential non-specific cross-reactions. This type of plate can be used as a blocking solution with inert protein or non-ionic detergent.

   3) Aminated

   After surface modification treatment, this kind of ELISA plate possesses positively charged amino groups, and its hydrophobic bond is replaced by hydrophilic bond. This type of ELISA plate is suitable as a solid-phase carrier for small molecule proteins. Using a suitable buffer and pH value, the surface can bind to small negatively charged molecules through ionic bonds. Due to the hydrophilic properties of the surface and the ability to covalently bind through other cross-linking agents, it can be used to immobilize protein molecules soluble in detergents such as Triton-100 and Tween 20. The disadvantage of this type of board is that due to the reduced hydrophobicity, some protein molecules cannot be combined; in addition, its surface needs to be effectively sealed. Due to the hydrophilic and covalent surface characteristics, the sealing fluid used must be able to interact with the non-reactive amino groups and any functional groups in the selected crosslinking agent.

   4. In addition, it is divided into transparent, black and white according to the color.

   The transparent one is the most commonly used, used for the most common enzyme-linked immunoassay. Compared with transparent boards, there are opaque boards used for luminescence detection, generally black and white. The black microtiter plate itself absorbs light, so its signal is much lower than that of the white plate, so it is generally used to detect stronger 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 ELISA plate can also reduce the problems caused by non-specific reactions. Some customers may ask whether luminescence detection is possible with a general ELISA plate. The answer is no, because generally the light emitted from the chemiluminescence reaction is isotropic, which means that it is emitted equally in all directions . If you use a transparent board, the light will not only diverge from the vertical direction, but also from the horizontal direction. It will easily pass through the gaps between the holes and the hole walls. In this case, the influence between adjacent wells will be great when the light is strong, so it is not possible to use a transparent ELISA plate for chemiluminescence experiments.

   Most of the enzyme-labeled plates you see now are detachable, that is, a single strip can be removed, and there are also fixed plates. A single detachable board can actually save a lot of money, because in this way, when you want to use a new microplate, you can remove the microplate strips and buy some microplate strips. Just consider The same model is required. In addition, the detachable ELISA plate can be used for in vitro testing, which is convenient for disassembly.