A variety of materials can be the solid phase of ELISA kits such as polyethylene, polyacrylamide, agarose, glass and silicone rubber. The ideal Elisa plates ought to have good adsorption performance, low blank value, high transparency. In addition, same size of very hole and identical performance are also the quality standard. The most commonly used substance is polystyrene for it is good at protein adsorption and does not damage the immune activity of a protein. It also have no effect on the immune response and the color reaction in ELISA. What’s more, it is inexpensive and is easy to get.
There are mainly three kinds of carriers in ELISA kits: microtiter plates, beads and small tubes. Microtiter plates are used most widely and the plates used for ELISA are called ELISA plates. The international standard wells of microtiter plates are 8×12. Elisa plates are characterized for that a large number of samples can be detected at same time and can read out the results in a special colorimeter quickly. Now there are a variety of automated instruments for microtiter plate detection of elisa, including loading, washing, insulation, colorimetric and other steps, which is beneficial to standardizing the operation.
Due to different raw materials and production process, there are some gaps between ELISA kits. It is suggested that check the quality before using. The common checking methods: utilize human IgG (10ng/mL) to coat every hole of the ELISA plate, adds anti-human IgG enzyme-labeled antibodies with appropriate dilution into every hole after washing, then washes after incubation, adds substrate.After the termination of the enzyme reaction, measures absorbance of dilution at every well. Controls the reaction conditions so that the absorbance value of each well is about 0.8 . Calculates the average of all readings. The mean difference between individual readings and all readings should be less than 10%.
For the other solid phase carriers, the beads are typically the balls of 0.6cm diameter and the surface increases adsorption area significantly after grinding treatment. The other feature of the beads is easy to wash, which is significant in the experimental procedures. Small tubes also have a larger surface adsorption as the solid phase carrier, thus reaction amount of samples enhance.