Antibody−antigen interaction dynamics revealed by analysis of single-molecule equilibrium fluctuations on individual plasmonic nanoparticle biosensors
Journal article, 2018

Antibody−antigen interactions are complex events central to immune response, in vivo and in vitro diagnostics, and development of therapeutic substances. We developed an ultrastable single-molecule localized surface plasmon resonance (LSPR) sensing platform optimized for studying antibody−antigen interaction kinetics over very long time scales. The setup allowed us to perform equilibrium fluctuations analysis of the PEG/anti-PEG interaction. By time and frequency domain analysis, we demonstrate that reversible adsorption of monovalently bound anti-PEG antibodies is the dominant factor affecting the LSPR fluctuations. The results suggest that equilibrium fluctuation analysis can be an alternative to established methods for determination of interaction rates. In particular, the methodology is suited to analyze molecular systems whose properties change during the initial interaction phases, for example, due to mass transport limitations or, as demonstrated here, because the effective association rate constant varies with surface concentration of adsorbed molecules.




Reaction rate constants


Equilibrium fluctuations


Srdjan Acimovic

Chalmers, Physics, Bionanophotonics

Hana Jungová

Chalmers, Physics, Bionanophotonics

Gustav Emilsson

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Lei Shao

Chalmers, Physics, Bionanophotonics

Andreas Dahlin

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Mikael Käll

Chalmers, Physics

Tomasz Antosiewicz

University of Warsaw

Chalmers, Physics, Bionanophotonics

ACS Nano

1936-0851 (ISSN) 1936-086X (eISSN)

Vol. 12 10 9958-9965

Subject Categories

Physical Chemistry

Analytical Chemistry

Condensed Matter Physics





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4/5/2022 1