AVS 45th International Symposium
    Biomaterial Interfaces Group Tuesday Sessions
       Session BI+AS+MM+NS+SS-TuA

Paper BI+AS+MM+NS+SS-TuA7
Nanomechanical Properties of Cellular Components Determined by Interfacial Force Microscopy

Tuesday, November 3, 1998, 4:00 pm, Room 326

Session: Nanoscale to Mesocale Biomaterial Structures
Presenter: P.R. Norton, University of Western Ontario, Canada
Authors: P.R. Norton, University of Western Ontario, Canada
K de Jong, University of Western Ontario, Canada
J.F. Graham, University of Western Ontario, Canada
N.O. Petersen, University of Western Ontario, Canada
Correspondent: Click to Email
The cell membrane is the contact surface between the cell's internal environment and the outside world. Increasingly it is recognized the there is strong active coupling between mechanical properties and cellular functions in properties such as locomotion and adhesion and in cytoskeletal diseases such as muscular dystrophy.@footnote1@ There is therefore an urgent need to understand the mechanical properties of cells and cellular subcomponents at length scales << 1µm. We will describe our initial experiments to achieve this goal. We have used three different imaging techniques in our investigation of the nanomechanical properties of larynx cells. First, immunofluorescent labelling was used to permit visualization of specific cell components in the confocal microscope, for example to determine whether the cell nucleus was removed in a shearing process. The same cell was then imaged in the atomic force microscope (AFM), permitting identification of components involved in motion such as microspikes. The nanomechanical properties of cells were then studied by nanoindentation using the interfacial force microscope (IFM).@footnote2@ While we have not yet succeeded in imaging and measuring the same cell used in the confocal and atomic force microscopies, we have demonstrated the feasibility of our approach and have obtained quantitative force-distance curves on different regions of a single cell fixed in paraformaldehyde, sodium periodate and lysine, which cross-links the proteins. From these data we can derive the elastic modulus, hardness etc of the specific region of the cell. The modulus of such a cell was ~ 3GPa, comparable to a soft polymer. Similar measurements are planned on unfixed cells. @FootnoteText@ @footnote1@Chen, C.S., et al. Science 276, 1425 (1997) @footnote2@Warren, O.L., et al. Physics in Canada 54, 122 (1998)