Three Dimensional Computational Modeling And Simulation Of Biological Cells And Capsules

Three-dimensional computational modeling and simulation are presented on the flow-induced motion of highly deformable particles which are representative of biological cells, such as red blood cells. We focus on the dynamics of capsules, that is, liquid drops surrounded by hyperelastic membranes. Unlike liquid drops where the fluid-fluid interface is characterized by isotropic surface tension, that for a capsule is governed by more complex constitutive laws. The numerical method is based on a front-tracking/immersed boundary method forcapsule deformation, and a finite-difference/fourier-transform method for the flow solver. The methodology is able to consider large deformation of capsules, capsule-capsule interaction, semi-dense suspension, and inertial effect. Using the simulation tool, we address a sequence of problems: (a) Capsule motion in wall-bounded pressure-driven flows: The motion of a capsule in a channel flow is investigated in absence of inertia and under large deformation. It is shown that a deformable capsule slowly drifts lateral to the flow and away from the wall while moving axially with the flow. Based on the theory of small deformation, and the present numerical results, an approximate expression for migration velocity under large deformation is developed. (b) Binary interaction in wall-bounded pressure-driven flows: Hydrodynamic interaction between two capsules in a channel flow is investigated in absence of inertia. Effect of wall proximity on the shear-induced diffusion process, in which one capsule rolls over the other, is studied for spherical and ellipsoidal resting shapes. (c) Effect of inertia on binary collision: Hydrodynamic interaction between two capsules in a linear shear flow is investigated in presence of inertia. The shear-induced diffusion process is shown to be absent. Instead, a new interaction mode is found in which the capsules engage in spiraling motion. (d) Simulation of semi-dense suspension: We then consider direct numerical simulations (DNS) of suspension of multiple capsules of spherical and biconcave resting shapes. Detailed analysis of the numerical results and their relevance to in vitro blood flow are presented. It is shown that the two-phase model of blood in microvessels underpredicts the DNS flow rate. We proceed to develop a three-layer model based on the microrheology extracted from the DNS, and show that it accurately predicts the DNS velocity.

In the past three decades, considerable progress has been made in the mathematical analysis, modelling, and simulation of the fluid dynamics of liquid capsules and biological cells, and interest in this area is now at an all-time high. This book features a collection of chapters contributed by acknowledged leaders in the field who explore topics re

In the past three decades, considerable progress has been made in the mathematical analysis, modelling, and simulation of the fluid dynamics of liquid capsules and biological cells, and interest in this area is now at an all-time high. This book features a collection of chapters contributed by acknowledged leaders in the field who explore topics related to the modeling and numerical simulation of capsule fluid dynamics and cell biomechanics. While providing an outstanding overview of the state of the art in selected areas of the subject, the authors also present the results of their own original research. A companion Web site holds useful links and additional information related to the topics discussed.

Spanning biological, mathematical, computational, and engineering sciences, computational biofluiddynamics addresses a diverse family of problems involving fluid flow inside and around living organisms, organs, tissue, biological cells, and other biological materials. Computational Hydrodynamics of Capsules and Biological Cells provides a comprehen

Computational modeling is emerging as a powerful new approach to study and manipulate biological systems. Multiple methods have been developed to model, visualize, and rationally alter systems at various length scales, starting from molecular modeling and design at atomic resolution to cellular pathways modeling and analysis. Higher time and length scale processes, such as molecular evolution, have also greatly benefited from new breeds of computational approaches. This book provides an overview of the established computational methods used for modeling biologically and medically relevant systems.

This textbook provides an introduction to dynamic modeling in molecular cell biology, taking a computational and intuitive approach. Detailed illustrations, examples, and exercises are included throughout the text. Appendices containing mathematical and computational techniques are provided as a reference tool.

This unique text explores the use of innovative modeling techniques in effecting a better understanding of complex diseases such as AIDS and cancer. From a way of representing the computational properties of protein-folding problems to computer simulation of bimodal neurons and networks, Computer Modeling and Simulations of Complex Biological Systems examines several modeling methodologies and integrates them across a variety of disciplines. This interdisciplinary approach suggests new ways to solve complex problems pertaining to biological systems. Written in clear and simple terms appropriate for both the novice and the experienced researcher, the book presents a step-by-step approach to the subject and includes numerous examples that explain the concepts presented in the text.

Three-dimensional computational modeling and simulations are presented on the rolling motion of a deformable cell on an adhesive surface in shear flow. The problem is motivated primarily by the adhesive rolling motion of white blood cells or leukocytes in response to inflammation in the body. The methodology is based on an immersed boundary method to predict cell deformation, and a Monte Carlo simulation to model the random formation and breakage of the adhesion bonds formed between a ligand-bearing cell and a receptor-coated surface. The multiscale and multiphysics modeling developed in this study allows us to resolve the complex coupling between the hydrodynamics, the deformation dynamics of the cell, and the biophysics of the adhesion bonds. In the thesis, we address the sequence of events that are encountered in the multistep process of cell rolling, namely, the initial arrest of the cell, followed by its deformation and spreading on the substrate, and the subsequent quasi-steady rolling motion. We provide phase diagrams for cell adhesion/escape, and showed that the hydrodynamic lift, that exists on a deformable cell in the wall-bounded motion, plays a major role in the process. The experimentally observed 'stop-and-go' motion of the cells is predicted in our simulations. After providing results on the general adhesive rolling motion, we focus specifically on the rolling dynamics of the leukocytes, and study the effect of cell deformability, shear rate and cell concentration on the instantaneous and time-averaged rolling characteristics. We also study the biophysical characteristics of the adhesion bonds during the rolling process. Finally, we consider the effect of the adherent leukocytes on the surrounding flow in terms of the changes in tracer dispersion and the vascular flow resistance. Comparison with experimental measurements (in vitro and in vivo) is presented throughout the thesis.

This book presents a theoretical and practical overview of computational modeling in bioengineering, focusing on a range of applications including electrical stimulation of neural and cardiac tissue, implantable drug delivery, cancer therapy, biomechanics, cardiovascular dynamics, as well as fluid-structure interaction for modelling of organs, tissues, cells and devices. It covers the basic principles of modeling and simulation with ordinary and partial differential equations using MATLAB and COMSOL Multiphysics numerical software. The target audience primarily comprises postgraduate students and researchers, but the book may also be beneficial for practitioners in the medical device industry.

CD-ROM contains: Maya files, MEL scripts, and rendered animation from various chapters.