Nature doesn’t need labels.
Neither do we.
Many conventional bioassays use an immobilized ligand to capture a target analyte from solution, before employing specialized detection reagents to analyze the interaction between the two molecules.
However, a main drawback of traditional techniques is that they often require individual bioassay components to be labeled, such that detection is possible using reagents incorporating enzymes or fluorescent dyes to provide a measurable readout. Not only can labeling alter ligand structure and/or function to skew experimental results, but the labels themselves can bind non-specifically to other bioassay components to produce unwanted background signal. Non-specific binding can especially be problematic when working with complex samples like cell culture supernatants, serum, or plasma.
Real-time monitoring without artificial manipulation
What is label-free technology?
Bioassay techniques such as enzyme-linked immunosorbent assay (ELISA) or bead-based flow cytometry use labeled reagents to detect and monitor biomolecular interactions, typically providing results that are representative of a fixed point in time. Label-free technology (also label-free detection or label-free sensing) instead uses impedance- or optics-based biosensors to measure the changes that occur upon analyte binding to a ligand immobilized on a biosensor surface. This approach enables the interaction to be monitored in real-time without artificial manipulation of the individual assay components.
A defining feature of label-free technology is the method used for ligand immobilization. Unlike conventional bioassay techniques that use labels to promote ligand attachment to the surface of a bead or a microplate well, label-free technology allows native ligand to be immobilized on a biosensor surface. Label-free ligand immobilization is typically achieved by covalently coupling the ligand to the biosensor via naturally-occurring amine (-NH2), thiol (-SH2) or aldehyde (-COOH) groups, or through ligand attachment to an antibody that has itself been covalently attached to the biosensor surface.
Get an overview of how label-free technology differs from traditional bioassay techniques below.
More physiologically relevant insights
Benefits of label-free technology and why to use it in Drug Discovery
A major advantage of label-free technology is that it allows the ligand to retain its native conformation and biological activity. This provides more physiologically relevant insights into the underlying biology than using a ligand that has been synthetically modified.
Additionally, by avoiding the need for labeled detection reagents such as enzyme-conjugated antibodies or fluorescently-labeled proteins, label-free technology eliminates the risk of unwanted background signal that can arise when labels bind non-specifically to other bioassay components. This is especially beneficial when working with complex sample material that contains numerous components besides the analyte of interest.
Importantly, label-free technology allows researchers to carry out analyses that are simply not possible using conventional methods that provide only end-point results. These include kinetic and affinity analysis, and evaluation of binding specificity, which are enabled by the dynamic, real-time interaction analysis afforded by label-free monitoring.
Listen to Dr. Tatiana Tiago, Product Manager at Creoptix, and find out more about the benefits of label-free technology.
Creoptix Label-Free Solutions
The Creoptix® WAVEsystem enables researchers to perform label-free molecular interaction analysis both intuitively and cost-effectively and can be used to provide answers to a broad range of scientific questions. These include determining whether two molecules are interacting, how specific the interaction is, and what affinity the molecules have for one another, as well as confirming the biologically active concentration of a specific analyte in a sample.
It is also possible using the Creoptix WAVEsystems to establish critical reaction parameters such as the association rate constant (ka), dissociation rate constant (kd), and the equilibrium dissociation constant (kD), all of which inform analyte-ligand binding in real-time.
By combining the propitiatory Grating-Coupled Interferometry (GCI) technology with no-clog microfluidics, the Creoptix® WAVEsystems deliver high quality data from even the most challenging sample types and achieve superior resolution in signal and time compared to other forms of label-free detection.
And to streamline data generation and analysis, the integrated, user-friendly WAVEcontrol software offers expert guidance through experimental set up, kinetic evaluation and report generation to ensure results you can trust.
Find out how GCI label-free technology is accelerating Drug Discovery
1) Poster with focus on GCI Technology
Get this poster and learn how the proprietary GCI label-free technology from Creoptix delivers superior sensitivity compared to traditional label-free technologies: everything summarized on one page.
2) Technote with focus on Small Molecules
In this benchmarking technote we demonstrate the power of GCI label-free technology (in combination with waveRAPID) in streamlining the kinetic characterization of large numbers of drug hit compounds, with results comparable to SPR.
3) Technote with focus on Biologics
In this technote we show how the WAVEsystem with its underlying GCI label-free technology can be used for the characterization of binding affinity and kinetics of antibodies raised against SARSCoV-2 in clinical human blood plasma samples.
Want to know more?
Reach out to one of our experts to learn more about label-free detection and GCI technology.