Quantification of Multivalent Interactions by Tracking Single Biological Nanoparticle Mobility on a Lipid Membrane

• DOI: 10.1021/acs.nanolett.6b01511
• Publication Date: 2016-05-31T09:10:25Z
• Authors: Stephan Block; Vladimir P. Zhdanov; Fredrik Höök
• Keywords: Cholesterol; Cell Membrane; Lipid Bilayers; Virion; Nanoparticles; DNA

Macromolecular association commonly occurs via dynamic engagement of multiple weak bonds referred to as multivalent interactions. The distribution the number bonds, combined with their strong influence on residence time, makes it very demanding quantify this type interaction. To address challenge in context virology, we mimicked virion a cell membrane by attaching lipid vesicles (100 nm diameter) supported bilayer multiple, identical cholesterol-based DNA linker molecules, each mimicking an individual virion-receptor link. Using total internal reflection microscopy track single attached novel filtering approach, show that histograms vesicle diffusion coefficient D exhibit spectrum distinct peaks, which are associated differing number, n, linking tethers. These peaks only observed if transient changes n excluded from analysis. is found be proportional 1/n, excellent agreement free draining model, allowing level and extract transition rates between states. Necessary imaging conditions extend analysis interactions general also reported.