Wash Buffer: Definition & Overview

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Definition: Wash Buffer

Lab experiments need to be carefully performed in order to achieve reliable and accurate results. Especially when it comes to high-throughput assays that require quality and expensive reagents such as immunoassay, ELISA, and immunohistochemistry. 

While performing these assays, you need to ensure that there is an efficient antibody-antigen interaction to achieve desired results. This is a sensitive process where even a small mistake in blocking and washing the plate surface can cause the assays to fail.

In addition to being meticulous when performing the blocking and washing steps, high-quality reagents must be used to prepare solutions and buffers. In the blocking step, the blocking buffer is used to block the membrane, while in the washing step, the washing buffer is used.

But what are these buffers? 

A blocking buffer is a mixture of proteins and other compounds that passively bind to the remaining binding surfaces on the assay plate to reduce background interference and produce quality results. 

Wash buffer (or washing buffer) is a high-performing washing solution used in a range of assays performed in life sciences research and industrial labs.

The washing step comes after the incubation step of the assays. It’s done to remove excess and unbound components that could interfere with assay results.

In this article, we will cover detail on wash buffers, including their types, how they are prepared, and their uses in lab applications or assays.

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Wash Buffer Overview

Wash buffers are designed for a range of immunoassays and techniques like ELISA, western blotting, and immunohistochemistry.

They are used in assays to wash enzyme conjugate, antigen/antibody, sample, and standard from the substrate surface. This reduces the background noise and produces efficient clean results.

Wash buffers are prepared differently using different formulations and components based on the technique required for use. For example, there are wash buffers prepared with different bases such as TRIS or PBS and with or without detergents.

The buffer is commonly supplied as 30X concentrate and can remain stable around 2°-8°C for about a month. However, it should be diluted before use and the diluent should be utilized within a week.

Washing Technique

Assays may require different washing techniques. However, here are some common washing steps involved in lab assays:

  • 30X concentrate wash buffers are available in the market but generally, a 1X formulation is used in assays. 
  • Prepare a 1X working solution by diluting 1 mL of TBS Wash Solution (10X Concentrate) in 9 mL of reagent quality water.
  • Equilibrate the working solution at room temperature (25°C) before use.
  • Treat and cover the target surface using a 1X working solution.
  • Discard the solution and again repeat the washing step.

Decide the number of washes, length of wash time, and dilution of wash concentrate based on the assay you wish to perform.

Refer to the manuals or documents that come with the product for the recommended procedure by the product manufacturer.

Wash Buffer Applications

Wash buffers are used in a range of assays, such as immunoblotting, protein chip procedures, ELISA, western blotting, immunohistochemistry, among others. Its primary role is to wash all excess and unbound components from the reaction surface to reduce the interference and non-specific binding.

It’s recommended to look at the certificate of analysis, safety data sheet (SDS), and other manuals that come with the product to refer to the quality of the product and suggested procedures for the particular assay. 

Now, webinars and technical support are also provided by the product manufacturers and suppliers to the customers to address their queries and concerns related to the products.

You can also look to the citations mentioned by the distributors for the validation of the product results claimed by them. Often FAQs mentioned on the product website are also useful to gain insights on the acquired product.

ELISA

Enzyme-linked immunosorbent assay (ELISA) is a commonly used immunological assay to measure proteins, antibodies, antigens, and glycoproteins in different biological samples. 

In an ELISA assay, the excessive and unbound material is washed off using a high-affinity antibody, which makes it an extremely powerful test.

A variety of ELISA wash buffers are commercially available from different commerce platforms. For example, some provide ELISA wash buffers to be used with either direct ELISA or antibody-sandwich ELISA applications. However, some offer TRIS-based wash buffers suiting cytokine and sandwich-ELISA.

Wash buffers can be purchased separately or as part of a complete ELISA kit from a distributor.

Immunohistochemistry

Immunohistochemistry is an immunostaining technique used to visualize the distribution and localization of cellular components within cells by using labeled antibodies with specific antigens in cells.

For the assay, a wash buffer without Tween 20 or other detergents is recommended. The presence of these components interferes with the assay and results in false negatives and false positives.  

Western Blot

Western blot is a widely used technique in life sciences labs to detect specific proteins in a crude sample. 

In the washing step of the assay, a low concentration detergent solution is used after incubating the membrane with highly concentrated antibodies. The most preferred solutions are 0.05% to 0.1% Tween™ 20 in PBS or TBS buffers. 

Chromatography

Chromatography is a commonly used analytical technique used in labs to separate a mixture into its individual components. Here, washing buffers are used to wash off all or any unwanted materials or proteins.

Wash Buffer Industries

Wash buffers are an essential solution used in a range of life science labs and industries to facilitate purification, localization, or distribution assays. It has a huge role in obtaining great results while studying the interactions between the biomolecules. Below are two areas that extensively utilize wash buffers in their assays.

Biochemistry

In biochemistry labs, wash buffers are used in assays such as ELISA and western blotting to study proteins, glycoproteins, and other molecules. 

Biotechnology

In the biotech field, wash buffers assist in the washing step of a variety of assays including immunoassays, immunohistochemistry, ELISA, and chromatin immunoprecipitation (ChIP) assays. These assays are a powerful tool to study the specific antibody-antigen interaction, studying cellular components, and protein purification or detection.

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Wash buffers are one of the essential solutions used in life science labs. Chemically it’s either a tris or PBS buffer with a detergent. However, some assays like immunohistochemistry workflows require a washing buffer without tween or any other detergent.

A washing buffer is used in the washing step of assays, such as ELISA, western blot, and immunoassay. This helps to remove and wash off all the excessive and unbound proteins or compounds from the plate surface. 

It increases the efficient binding between the molecules, such as binding of a specific antibody with an antigen, reduces background noise, and generates quality results. Washer buffers also provide numerous in vitro diagnostic (IVD) uses.

However, to produce reliable and accurate results, you’ll need more than a high-quality wash buffer. You need high-tech instruments that can go along with high-throughput assays.

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The leasing solution protects you from paying expensive upfront costs and allows you to either acquire a piece of equipment or outfit your whole lab. The program is customizable so it can be tailored according to your lab needs. 

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