Binding increases the amount of material at the sensor surface, changing the local refractive index. The instrument records this change as a shift in the surface plasmon signal while the analyte flows across the immobilized antibody, antigen, or other binding partner. Because the response occurs during the interaction, researchers can follow binding in real time.
The association curve describes signal changes as the analyte binds, whereas the dissociation curve follows the interaction after binding conditions change and the complex separates. Examining both phases allows researchers to evaluate binding kinetics, including how rapidly an interaction develops and how long it persists. These measurements also support affinity assessment.
A measurable signal shows that material accumulated at the sensor surface, but interpretation also depends on whether the interaction reflects the intended molecular recognition event. Comparing the binding behavior of selected immune or infection-related partners helps assess specificity. This distinction is important when characterizing antibody-antigen recognition, host-pathogen interactions, or candidate therapeutic binding.
Because the assay does not require a detection label, the recorded response comes from the binding-related refractive-index change at the sensor surface rather than from a separate signal-generating tag. This supports direct, real-time observation of the interaction. Researchers can therefore focus on kinetic behavior, affinity, and specificity for the molecular pair being studied.
The assay begins with immobilization of one interaction partner on a sensor surface, followed by passage of the analyte across that surface. The instrument monitors the resulting plasmon-signal shift as binding occurs and as the interaction dissociates. Researchers then analyze the association and dissociation curves to extract kinetic, affinity, and specificity information.
In immunology, the method can characterize how antibodies recognize antigens and can compare the resulting interaction behavior through binding kinetics, affinity, and specificity. These measurements support studies of immune recognition and can inform biomarker development, vaccine research, and diagnostic assay design. The real-time format is especially useful when researchers need interaction data rather than only endpoint detection.
Researchers can apply the assay to host-pathogen interactions and to the evaluation of candidate therapeutics. By measuring how interaction signals develop and decline, they can determine whether relevant molecular partners bind and assess the strength and persistence of those interactions. These results can contribute to understanding infection-related recognition and to selecting candidates for further investigation.