Single molecule force spectroscopy to determine specific receptor densities on live cancer cells under varying conditions*

We have used atomic force microscopy to study the single-molecule interaction between the ligand and receptors in live cancer cells under different conditions. We particularly focused on discoidin domain receptors (DDR), an important player in cancer metastasis. DDRs are receptors that dimerize in response to collagen and initiate a signaling chain within the cell. To mimic the cancer environment, we constructed gel substrates of varying stiffness and collagen concentration. The goal of the research is to determine receptor levels, dynamics and interactions as a function of cell type and environment. Using an improved AFM analysis method, we were able to determine not only binding probability and kinetic parameters, but also ligand densities. We will present preliminary results from this research.