Enzyme Linked Immunosorbent Assay (ELISA)

Enzyme Linked Immunosorbent Assay is to bind a known antigen or antibody to the surface of a solid phase carrier, then uses an enzyme-labeled (conjugated) antibody or antigen to incubate with it, and develops color through a chromogenic material. Its color depth is proportional to the content of the substance to be tested, which can be observed with the naked eye.

ELISA is an immunological assay commonly used to measure antibodies, antigens, proteins and glycoproteins in biological samples. ELISA assays are generally carried out in 96-well plate or 384-well plate to allow multiple samples to be measured in a single experiment.

• Coating
  Immobilize antigens to the surface of polystyrene microplate wells directly or indirectly.
• Blocking
  Add irrelevant protein or other molecule to cover all unsaturated surface-binding sites of the microplate wells.
• Detection
  Incubate with antigen-specific antibodies that affinity bind to the antigens.
• Readout
  Add substrate and measure the signal produced by the enzyme-substrate reaction.

Fig. 1 The basic flow chart for ELISA.

• Direct ELISA
  The antigen is immobilized in the well of an ELISA plate. The antigen is then detected by an antibody directly conjugated to an enzyme such as HRP.
• Indirect ELISA
  The antigen is adsorbed to a well in an ELISA plate. An antigen-specific binding antibody was added and incubated briefly. Add an antibody to detect the first binding antibody which is usually conjugated to an enzyme.
• Sandwich ELISA
  Sandwich ELISA requires the use of matching antibody pairs (capture and detection antibodies). Thus, each antibody is specific for a different and non-overlapping region or epitope of the antigen. The matching antibody pairs are specifically tested in sandwich ELISA to ensure that they detect different epitopes to obtain accurate results.
• Competitive ELISA
  Competitive ELISA relies on the competitive reaction between the sample antigen and antigen bound to the wells of microtiter plate with the primary antibody.

• Give an accurate diagnosis of a particular disease as two antibodies are used.
• Carry out for complex samples since the antigen is not required to get purified to detect.
• Highly responsive because direct and indirect analysis methods can be performed.
• Rapid test and quick results.
• Detection methods range from the quantitative, semi-quantitative, standard curve, qualitative, calibration curve models, etc.
• Easier to perform and simple process as compared to other assays which require the presence of radioactive materials.

• Determine the presence of antibodies and antigens in a sample.
• Detect any food allergens present in the food industry.
• Determine the concentration of serum antibody in a virus test.
• Diagnose diseases, such as Ebola, Pernicious anaemia, AIDS, Rotavirus, Lyme disease, Syphilis, Toxoplasmosis, Zika virus and Carcinoma of the epithelial cells.

Laboratory Centrifuges

A centrifuge is any device that applies a sustained centrifugal force—that is, a force due to rotation. The widest use of centrifuges is for the concentration and purification of materials in suspension or dissolved in fluids. Suspended particles denser than the suspending liquid tend to migrate toward the periphery, while those less dense move toward the centre.

Vortexer

Vortexers, or vortex mixers, have very fast, small orbits (usually between 2 and 4 mm) and they are named for their ability to form a vortex in the liquid that they are mixing. are commonly used in laboratories to mix small liquid volumes for cell disruption or homogenization. Constructed of rugged, corrosion-resistant materials, the instruments will endure heavy everyday usage.

Laboratory Refrigeration

Laboratory refrigerators are designed with special features and options for use in the laboratory, including a range of refrigerator and freezer accessories. The primary function of a laboratory refrigerator is to maintain a defined, internal storage temperature in order to provide secure storage and protection of temperature-sensitive products, samples, specimens, chemicals, drugs, solutions, and other substances.

Microplate Washers

Microplate washers are used to remove reagents from sample wells on microplates and to prepare them for the next step in an assay or procedure. The process involves the dispensation of a wash solution, which, through a series of buffer dispensations and aspiration cycles, removes unbound liquid contents from the wells of the microplate, while allowing bound products to remain. The wash solution is then removed via vacuum suction.

Pipette

Pipette is a small piece of apparatus which typically consists of a narrow tube into which fluid is drawn by suction (as for dispensing or measurement) and retained by closing the upper end. Pipettes are a common laboratory tool and come in a multitude of channels, displacements and construction materials. There are different pipettes for all kinds of uses within the lab.

Laboratory Incubators

An incubator is a device used to grow and maintain microbiological cultures or cell cultures. It is made up of a chamber with a regulated temperature. An incubator maintains optimal temperature, humidity, and other conditions such as the CO₂ and oxygen content of the atmosphere inside. Incubators are essential for much experimental work in cell biology, microbiology, and molecular biology.

Microplate Readers

A microplate reader is a laboratory instrument that is used to measure chemical, biological or physical reactions, properties, and analytes within the well of a microplate. A microplate reader detects light signals produced within a specific wavelength range by samples that have been pipetted into a plate. It is used for the quantification of several biological and chemical assays in a microplate.

STEMart provides you with a variety of ELISA equipment or consumables to meet your various R&D and application needs. If you have any questions or requirements for ELISA, please feel free to contact us.