Friction Measurements on Living Hela Cells

Abstract

<p> This thesis is a study of the adhesive behaviour of HeLa cells using a novel instrument designed for measuring both the shearing and compression force applied to the cells. For these experiments a micropipette forged as a double cantilever is used to grasp and manoeuvre a cell onto a silicon or Poly-L-Lysine (PLL) coated substrate. The substrate is then moved perpendicularly with respect to the micropipette tip thereby sliding and shearing the cell across the surface. The perpendicular and parallel deflection of the cantilever enables us to directly measure the friction and normal force. A new approach for calibrating both sections of the cantilever has been developped and will also be presented in this work. As a proof of concept, the experiment is also performed with a polystyrene bead. The polystyrene bead, a simpler system, manifests some of the typical results expected from friction experiments. </p>