Single-molecule imaging of protein dynamics in living cells for signal transduction study: e.g. monitoring the protein diffusions to study their activation, internalization and recycling; measuring the intensities to study their stoichiometry. Results from monitoring the dynamic changes provide valuable information to enhance our understanding of cellular process and mechanism of drug effect.  

With the immobilization of AFM tip with a specific molecule, AFM based single molecule force spectroscopy (SMFS) enables real-time measurements of specific interaction forces of individual ligand-receptor pairs in living cells, offering a new approach to investigate the formation of cell signaling complex, and understand the molecular mechanism of signal transduction inhibitor and therapeutic drugs. Without specific molecule immobilization on AFM tip, the force curves are obtained to study cell elasticity.