Biophysical Studies of Molecular and Cellular Systems Using AFM

When: Friday, October 28, 2011 at 12:30 pm
Where: DA 114
Speaker: Dr. Gina-Mirela Mustata
Organization: Northewestern University, Evanston, IL
Sponsor: Physics Seminar

Atomic force Microscopy (AFM) is a very powerful tool in the study of biological questions at levels where other methods fail. Fluid AFM made possible the study of cellular and sub-cellular processes in biological significant conditions. While at its invention, the AFM was presented as an instrument capable of mapping the topological features of the samples, in more recent years, the development of various modes of operation has made possible the investigation of processes and events happening below the surface.

Combining AFM and single particle tracking in a Total Internal Reflection Fluorescence set-up it is possible to visualize the cytoskeletal organization of different cells with different functions. The cytoskeleton re-organization is one of the most important features of certain diseases which leads not only to changes in cell morphology, but also to variations in mechanical properties of the affected cells. Using AFM we have been able to probe the changes in micro-mechanical properties of the human pulmonary arterial endothelial cells when undergoing highly distressing physiological events in Acute Lung Injury/Acute Respiratory Distress Syndrome.

Another field where AFM provides a wealth of information is the investigation of the mechanism by which certain peptides, called amyloids, disrupt the cellular function in a multitude of diseases called amyloidosis. It is speculated that these peptides incorporate themselves into cell membranes. We have studied and characterized the behavior of these peptides from their self-assembly into long and dynamic fibrils to their interaction with supported lipid bilayers and cell membranes.

From the detection and characterization of single molecules to the visualization and mechanical probing of more complex systems such cells and tissues, scanning probe microscopy has proved to be a versatile technique when it comes to biophysics and opened the way to non-invasive investigation of real time dynamic processes at scales inaccessible to other techniques.