Elastic theory for the deformation of a spherical dielectric biological object under electro-optical trapping

Abstract

The shear modulus of a dielectric spherical particle is investigated using a combination of triangular (or square) electrodes and a single-beam optical tweezer. The electronic response of a spherical dielectric particle is dominated by the local interactions with the trapping beams. Positive dielectrophoresis on a dielectric particle works at high frequencies. By measuring the geometrical parameters of the sphere as a function of the applied voltage, the elasticity of sphere is determined theoretically from the maximum applied voltage when a particle escapes to the electrode from trapping centre. To check the validity and efficiency of the elasticity derived mathematically, similar experimental results obtained by other techniques have been studied. The method is suggested to be a general tool to distinguish healthy and diseased cells.