Those who work within the medical sector would have heard of the term ‘coating buffer’ at least once in their lifetime. Especially over the past 2 years, during the COVID-19 pandemic, this term has cropped up in many institutions such as hospitals and laboratories.

Their main use is to absorb and immobilize any antibodies on surfaces such as plastic microtiter plates. They are also used in various other protein binding surfaces.

This measure of control is crucial when working with substances such as proteins and antibodies with certain pH levels. These levels have a significant impact on the efficiency and coating buffers that have a pH of between 7.4 and 9.6 are ideal.

A solution known as the ELISA Plate Coating Solution is commonly used as the saline solution, which contains a blend of dibasic phosphates and monobasic phosphates, and can be used in most systems, which are known as the ELISA systems. The full name of which is ‘enzyme-linked immunosorbent assay,’ and further information about it can be found here

The ELISA (enzyme-linked immunosorbent assay)

ELISA is an assay is a plate-based system intended for use to measure and detect substances within other solutions to pick up on various entities such as hormones, antibodies, peptides and proteins, to name a few. There are also other similar technologies such as the IEA or immunoassay which works similarly.

The technique involves separating the macromolecules inside of a microplate and then an antibody is mixed with it so as to perform the detection. The interaction of the antigen and antibody is key here https://ruo.mbl.co.jp/bio/e/support/method/elisa.html

There are a few different methods of ELISA used namely:

• Competitive
• Sandwich
• Indirect
• Direct

We take a brief look at each of these below.

The Different Types of ELISA

Sandwich Method

In this type of system, the two types of antibodies used are combined with two different types of epitopes on the antigen. This results in the antibody being tied to the bottom of the microplate. This makes it easier to detect, and if not, then a second antibody is added to the solution.

Competitive

A similar antibody to the antigen is added to the wells and if the sample shows a presence of an antigen then it typically binds with the antibody, and anything that is not will be washed away in the samples. With this method, if the antigen presence is higher then its predecessor will be lower.

Direct

In the direct ELISA method, the molecules are also bound at the bottom of the plates. Detection is easier when the antigen attaches itself to a specific enzyme or molecule.

Indirect

Here an antibody that is specific to the molecule is added to the plate, an example would be the elisa coating buffer along with a second one, to detect any substances which are attached to the saline solution.

A Viable Solution to Certain Health Problems

Because the conventional ELISA technique would take a longer time to produce results, including the wash steps and multiple incubations needed, some kits are provided that take half the time and show results in as little as 90 minutes.

This is used in various other industries besides the medical, for instance, food and beverage industries to find any traces of gluten in commercially available drinks such as beer. Gluten is a substance commonly found in pieces of bread and cereals, as well as other food items that contain barley, wheat, and certain types of grains and rye as part of their ingredients.

With a growing number of populations suffering from celiac disease, this plays a significant part in the manufacturing of various beverages. Both food and drinks contain gluten, and those with this disease can suffer from various immunity disorders and chronic digestion problems. If this is not controlled it could lead to your small intestines being damaged.

These items must contain less than 20 ppm or parts per million of gluten to be safe for consumption, and one of the best tests methods is by use of the ELISA and coating buffer. Some people cannot stand any traces of the substance and having a kit can help curb potentially dangerous health problems. Anything from toxic peptides to prolamins from barley or rye, and gliadins which are a part of wheat, can cause an adverse reaction.

Why Buffers Are Essential for Experiments

There are many reasons as to why buffers are used in labs to produce results, however, some of the main ones include helping to increase the stability, and sensitivity of the ELISA. Different ones help to tackle different issues, for example, unwanted proteins, matric interferences and non-specific binding, and as a holistic approach the more it is used, the better researchers can improve on the technology.

Many have heard of the phrase ‘false positive’ results when taking certain tests, and using a buffer can help to reduce this risk.