Probing Single Virus Binding Sites on Living Mammalian Cells Using AFM

Area of Science:

• Biophysics
• Cell Biology
• Nanotechnology

Background:

• Atomic force microscopy (AFM) has advanced as a multiparametric tool for probing biological samples.
• Force-distance curve-based AFM (FD-based AFM) allows high-resolution imaging of living cells and characterization of ligand-receptor binding.
• Investigating virus-cell interactions is crucial for understanding infection dynamics.

Purpose of the Study:

• To present a method using FD-based AFM to study virus binding to living mammalian cells.
• To quantify kinetic and thermodynamic parameters of single virus-receptor-mediated binding.
• To analyze the free-energy landscape of these interactions.

Main Methods:

• Utilizing force-distance curve-based AFM (FD-based AFM) for high-resolution imaging.
• Probing specific interactions between a model virus and cells expressing its cognate receptor.
• Measuring binding affinity and characterizing multivalent interactions.

Main Results:

• FD-based AFM successfully investigated virus binding to living mammalian cells.
• The affinity of the virus-receptor interaction was quantified.
• Viruses rapidly established specific multivalent interactions, with each sequential bond strengthening cell attachment.

Conclusions:

• FD-based AFM is a powerful technique for studying virus-cell interactions at the single-molecule level.
• The study quantified the binding parameters and elucidated the role of multivalent interactions in viral adhesion.
• Understanding these interactions provides insights into viral entry mechanisms and host-pathogen dynamics.