Non-Specific Binding

Non-specific binding in an immunoassay may be a significant issue, especially those utilizing complex biological samples.

As part of our mission to improve the detection and treatment of disease, Surmodics™ IVD develops immunoassay reagents such as diluentsblockers, and more to reduce non-specific binding (NSB) while maintaining the intended assay signal. In the following overview, you will learn more about non-specific binding and more specifically, how best to overcome non-specific binding in your immunoassay.

What Is Non-Specific Binding?

Non-Specific binding (NSB) refers to an occurrence of an antibody binding to unintended proteins, receptors, or transporters. This binding of assay antibodies is not correlated with the specificity of the antibodies.

How Non-Specific Binding Most Frequently Occurs

Attraction of a primary or secondary antibody to Fc receptors (FcRs) is considered the leading contributor to unwanted binding events. In general, when an antibody binds to unintended proteins with considerably similar epitopes, non-specificity occurs.

Non-specific binding can result in a false positive and in turn, can negatively impact the proper diagnosis and treatment of disease. For immunodiagnostic assays, a false positive or false negative result can lead to a misdiagnosis of a disease or condition and improper treatment decisions. Clinicians and patients depend on the in vitro diagnostics (IVD) industry to develop high quality assays that deliver accurate results consistently.

With the increased use of antibody therapy, and animal-derived products being used to treat patients, the prevalence of heterophilic antibodies, human anti-mouse antibodies (HAMA), human anti-animal antibodies (HAAA), and rheumatoid factors, is becoming an increasing problem for assay developers. With immunoassays pursuing lower detection limits, multiplexing analytes, and higher sample through-put, the negative effects of heterophilic antibodies, HAMA and other matrix effects needs to be addressed. Surmodics IVD’s sample/assay diluents allow for the dramatic reduction of false positives in both in-house and commercially available kits, without having to sacrifice assay sensitivity.

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How to Overcome Non-Specific Binding

Surmodics’ Protein Stabilizers, Blockers & Diluents help to cut back non-specific binding while maintaining and even increasing signal-to-noise ratios. Review the following list of Surmodics’ immunoassay reagents designed to tackle non-specific binding in immunoassays.

Dried Protein Stabilizers & Blockers:

Surmodics’ IVD’s dried protein stabilizers and blockers, StabilCoat™, StabilGuard™ and StabilBlock™ offer assay developers unmatched stabilization of dried proteins and blocking efficacy in a one-step process. These immunoassay reagents are designed to preserve the conformation and activity of dried proteins coated on a wide range of surfaces, keeping antibodies and antigens at peak performance for long durations. At the same time, the blocking mechanisms in these reagents reduce non-specific binding of interfering proteins to maximize assay sensitivity. Our dried protein stabilizers and blockers are the industry gold standard for stability and blocking efficacy. The result is immediate improvement of assay performance in a one-step process for streamlined manufacturing.

Assay developers need numerous blocking mechanisms while selecting the antibody titration during assay optimization. Surmodics’ dried protein stabilizers and blockers provide alternative blocking mechanisms to achieve the best signal-to-noise ratios for each assay. With the introduction of StabilBlock, Surmodics now offers the best available reagent for reducing non-specific binding to boost immunoassay signal-to-noise ratios.

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Sample/Assay Diluents:

Due to the variability within patient samples, different blocking strategies are needed to dilute samples to achieve maximum assay performance. Both MatrixGuard™ and Surmodics™ Assay Diluent (Protein-Free) provide the gold standard in reducing false positives in your assay.

MatrixGuard (protein-containing) and Assay Diluent (protein-free) formulations provide two options to use when different methods are needed to block matrix interferences, while maintaining the clinical utility of the assay.

For IVD kit manufacturers requiring a strong, consistent blocking diluent across a variety of assays, Surmodics’ MatrixGuard Diluent provides unsurpassed blocking whereby matrix interferences are effectively blocked while the intended assay signal is maintained.

Unlike other diluents that either are marginally effective at blocking matrix interferences or alternatively block out true assay signal, MatrixGuard Diluent achieves the goal of maximum blockade of matrix interferences while simultaneously allowing signal to be maintained.

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Frequently Asked Questions

How Does Non-Specific Binding Work?

Non-Specific Binding (NSB) happens when a primary or secondary antibody binds to unplanned or unintended proteins.

Additionally, interference in an immunoassay, whether enzyme-linked immunosorbent assay (ELISA), radioimmunoassay, bead-based assays, or immuno PCR assays, has been a problem that continues to grow throughout the industry. Understanding how to overcome non-specific binding and immunoassay interferences is critical when building accurate and reliable immunoassays.

How Do You Prevent Non-Specific Binding?

Using optimal reagents in your immunoassay will help reduce the risk for non-specific binding and in turn, the risk for false positives and false negatives. Surmodics’ dried protein stabilizers/blockers and sample/assay diluents are specifically designed to reduce non-specific binding in immunoassays while maintaining and even increasing the intended assay signal.

Connect directly with one of our R&D Team members today to learn more about how to tackle non-specific binding in your immunoassay.

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