Colorimetric ELISA (Enzyme-linked Immunosorbent Assay) kits are essential tools for rapidly and accurately detecting the presence of specific antigens or antibodies in biological samples. These kits employ a straightforward, visual readout: a color change indicates the presence of the target molecule. They are highly popular in research environments for their ease of use, reliability, and compatibility with standard laboratory equipment, eliminating the need for specialized detection instruments. Our colorimetric SimpleStep ELISA kits are available for a broad range of analytes, sample types and species as sandwich or competitive assays.

Principle of colorimetric detection

Colorimetric ELISA kits use enzyme-substrate reactions that produce a visible color change. Typically, enzymes such as horseradish peroxidase (HRP) or alkaline phosphatase (AP) are conjugated to detection antibodies. Upon addition of a substrate, such as TMB (Tetramethylbenzidine) for HRP or BCIP/NBT (5-Bromo-4-Chloro-3'-Indolyphosphate p-Nitroblue Tetrazolium Chloride) for AP, the enzyme catalyzes a reaction that yields a colored product.

Benefits of using colorimetric ELISA

Ease of use

Simple procedure and visible readout that does not necessitate complex instruments.

Quantitative or semi-quantitative

Provides quantitative results based on the intensity of the color developed, which can be easily read by a standard plate reader.

Broad applicability

Suitable for a wide range of research applications in fields such as immunology, pathology, and biochemistry.

Colorimetric SimpleStep ELISAs

Our colorimetric SimpleStep ELISA are sandwich or competitive ELISAs with the same simple mix-wash-read workflow delivering results in 90 minutes.

^{Figure 1. SimpleStep ELISA technology allows the formation of the antibody-antigen complex in one single step, reducing assay time to 90 minutes.}

A conventional sandwich ELISA uses a pair of antibodies that bind to at least two distinct sites on the target protein. The capture antibody is pre-coated onto the well of a microplate and selectively binds to the target protein. After a wash step, the detector antibody is added and binds to a second site on the target protein to form a sandwich complex.

SimpleStep ELISA kits streamline this process using our CaptSure™ system, a one-wash system that forms the antibody-analyte sandwich complex in solution in a single step. In just one incubation and wash step, the complete sandwich complex forms in the well and is anchored to the plate with an immunoaffinity tag (figure 1).

Colorimetric competitive SimpleStep ELISA

Our competitive SimpleStep ELISA® kits deliver the same speed and simplicity as our sandwich format, with a 90-minute protocol. Designed for detecting small molecules and hormones with only one epitope, these kits use an affinity tag recognized by the plate’s monoclonal antibody, enabling single-step antibody–analyte complex formation and saving time at the bench. In the antigen-down (Figure 2) format, the labeled antigen and the unlabeled antigen from your sample compete to bind to the HRP-tagged capture antibody. In the antibody-down format (Figure 3), the HRP-tagged antigen and the unlabeled antigen from your sample compete to bind to the capture antibody. The component labeled with the CaptSure™ affinity tag, either antigen or antibody, binds to the SimpleStep ELISA® plate. A decrease in signal indicates the presence of antigen in the sample when compared to wells containing only the labeled antigen.

^{Figure 2. Competitive SimpleStep ELISA – Antigen down format.}

^{Figure 3. Competitive SimpleStep ELISA- Antibody down format.}

Benefits of our colorimetric SimpleStep ELISA kits

FAQ

What is the sensitivity of Colorimetric SimpleStep ELISA kits?

The sensitivity can vary depending on the specific kit and target. Our Simplestep ELISA kits rely on recombinant rabbit monoclonal antibodies for optimised sensitivity and specificity.

Can the colorimetric SimpleStep ELISA be used for all types of samples?

Yes, our kits are versatile and can be used with a variety of biological samples, including serum, plasma, cell culture supernatants, and tissue extracts.

What equipment do I need to use a Colorimetric SimpleStep ELISA kit?

A standard microplate reader capable of measuring absorbance in the visible range is required to quantify the intensity of color developed. Our kits are typically read at 450 nm.