Charles Eggleton and Ihab Sraj, Department of Mechanical Engineering

The mechanical deformation of biological cells is an efficient
experimental method to study the cellular properties and identify diseased
cells. Optical forces have been successfully used to induce small and even
large scale deformations that do not alter the cellular properties, mainly
due to minimal direct contact, compared to other experimental techniques
(micro-pipette aspiration, atomic force microscopy). A review on the recent
advances in the area of optical cell deformation shows that a variety of
deforming conditions can be imposed using different methods (optical
tweezers and optical stretcher) to simulate the different biological
conditions. Computational simulations, on the other hand, can be used to
guide and explain the experimental observations. In this work, we will
present a new numerical simulation of cell optical deformability using the
immersed boundary method. Cells are considered as 3D elastic capsules
immersed in a fluid. Optical forces are calculated using the ray optics
technique and applied on the capsule membrane that inducing transient Stokes
flow. The current study is primarily focused on the deformation of spherical
cells as well as biconcave discoid representing red blood cells. The
deformation pattern and relaxation time will be reported over a range of
forces.