Session: Advances in Spectroscopy:

Quantification of binding kinetics between drug and cell membrane protein is an essential step in drug evaluation. Current methods for measuring binding kinetics involve extracting the membrane protein and labeling, and both have issues. In our previous study, we have studied the in-situ quantification of molecular interaction on cell surface with surface plasmon resonance imaging (SPRi) and mechanical amplification detection. However, both of the methods mainly worked with fixed cells, as the live cell show big fluctuation noises. Here we present an optical imaging method to measure the molecular interaction with live red blood cells (RBC) by tracking the nanometer cellular membrane fluctuations. Red blood cells are fundamental for the nearly all basic physiologic dynamics and are able to interact with proteins, endothelial cells (ECs), platelets, macrophages, and bacteria. The mechanisms of molecule interaction of RBC are critical in both in health and disease study. By tracking the RBC membrane fluctuations during glycoprotein interaction, we measured the membrane fluctuation dynamics for binding kinetics quantification, analyzed the data with a hydrodynamic model, and determined the mechanical properties of the cells, including bending modulus and surface tension. Control experiment using fixatives reveals reduced membrane fluctuations, demonstrating the effect of cell fixations on the cell mechanical properties. We anticipate that the method will contribute to the understanding of the mechanisms of RBC interaction, and applications, such as mechanical assessment of cancer or other diseases at the single-cell level.

Molecular interaction detection with membrane fluctuations tracking. A. Schematic illustration of red blood cell membrane deformation before and after glycoprotein binding. B. Optical imaging system for real time molecular interaction detection. C. The glycoprotein binding curves and kinetics obtained from the red blood cell membrane fluctuations. D. The binding curve of cells fixed with different concentrations of fixatives

Molecular interaction detection with membrane fluctuations tracking. A. Schematic illustration of red blood cell membrane deformation before and after glycoprotein binding. B. Optical imaging system for real time molecular interaction detection. C. The glycoprotein binding curves and kinetics obtained from the red blood cell membrane fluctuations. D. The binding curve of cells fixed with different concentrations of fixatives

Fenni Zhang

Appearances