What is label-free interaction analysis and how to benefit from it?

Conventional bioassays, like enzyme-linked bioabsorbant assay (ELISA) or bead-based flow cytometry have relied on enzyme or fluorescent labels to detect target analytes. Unfortunately, these methods are fraught with non-specific binding issues that can skew the measurement results.

Basically, by removing the labels, we enable real-time monitoring without artificial manipulation.

So…what’s the challenge?

Label-based assays can only be used to measure an analyte’s interaction at a predetermined concentration and fixed point in time. This means that kinetic analysis isn’t possible.

In addition, the labels themselves can introduce issues. They are often not inert and can directly alter the molecular structure or function of the analyte, or create an unwanted background signal by interacting, non-specifically, with other bioassay components.

Unwanted interactions are a particular issue when working with complex samples. For example, cell culture supernatants, serum or plasma, where a wide range of, sometimes unknown, additional components may be present. 

Since labeled detection reagents are not required, label-free interaction analysis allows you full kinetic and affinity analysis, and evaluation of binding specificity, which simply isn’t possible with conventional techniques. This is all enabled through dynamic, real-time interaction analysis.

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How does it work?

The label-free ligand immobilization is typically achieved by covalently coupling the ligand to the biosensor using naturally occurring amine, thiol or aldehyde groups attached to the biosensor surface. Using this technique, the ligand is immobilized in its natural form.

Alternatively, the capture approach can be used for protein immobilization, taking advantage of a high-affinity interaction between the ligand and a capturing molecule that has been covalently immobilized on the surface.

Impedance or optics-based biosensors are then used to measure the analyte associating and dissociating with the ligand, giving valuable information about the kinetics and affinity of the binding interaction. Crucially, this is done in real-time, without artificial manipulation of the assay components.

What are the benefits?

Because label-free interaction analysis is a dynamic and real-time technique, it opens a whole new realm of evaluation. You can explore the kinetic and affinity analysis in real-time, alongside evaluation of the binding specificity, providing us more depth to the insight and answering a greater number of scientific questions, such as:

  • What affinity do the molecules have?
  • What is the binding kinetics between the two molecules?
  • What is the biologically active concentration of an analyte in a sample?

Our answer? GCI technology!

We help researchers make discoveries that simply aren’t possible with conventional bioassay methods. High-quality data can be derived from even the most challenging sample types with superior resolution and robustness.

The power behind this system is in the patented Grating-Coupled Interferometry (GCI) technology and non-clog WAVEchip microfluidics systems from Creoptix.

Are you ready for deeper insight?

GCI sensitivity combines with automated analytical control and innovative microfluidic technology. This provides a novel, optic biosensor platform for complete, real-time, label-free binding kinetics, which is called: the WAVEsystem.

Even the most challenging analytes can be quickly and easily analyzed to deliver deep insight into previously undetectable interactions.

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