One challenge with using Atomic Force Microscopy (AFM) for recognition microscopy on living cells is the fact that the cell is not rigid, and as the force is applied to a receptor site, it is not just the receptor site that is affected. The whole cell deforms under the applied force, and the measured binding force is a convolution of the local, intrinsic binding force of the receptor site and the gross elastic response of the cell. We have developed a model of the elastic deformation of the cell in order to separate the two effects, based on a continuum level analysis of the elastic deformation, including the incompressible interior and the tension and curvature of the membrane. A novel feature of this formalism are the treatment of the Canham-Helfrich curvature strain for finite deformations under load. As a validation, the model has been compared with force-displacement curves coming from AFM nanoindentation experiments on both membrane vesicles and cells. The model allows site-specific mechanical properties to be deconvoluted from the gross cell deformation in recognition microscopy experiments. Eventually, it may be possible to use concurrent multiscale modeling to provide a model of the atomistic interactions at the receptor site too.
Journal: TechConnect Briefs
Volume: 1, Technical Proceedings of the 2003 Nanotechnology Conference and Trade Show, Volume 1
Published: February 23, 2003
Pages: 138 - 141
Industry sectors: Medical & Biotech | Sensors, MEMS, Electronics