Biosurface Center

Mohamed Laradji, PhD
Donald Franceschetti, PhD

The Computational Biophysics group is involved in many areas of computational and theoretical modeling and simulation. Below are just a few examples of ongoing projects. For more information, contact the researchers listed above.

Diffusion in Confined Geometries
The picture at the right shows a snapshot of a lipid vesicle formed of two types of lipids embeded in a three-dimensional solvent. The kinetics of the phase separation process is governed by the competition between the interfacial tension between the two lipids regions and bending rigidity of the lipid bilayer. Eventually a full phase separation is achieved. This snapshot is obtained from a large scale simulation of 1.5 million particles (lipids + solvent particles). The simulations use the method of Dissipative Particle Dynamics of a molecular model." Dr. Laradji has initiated a collaborative project between Dr. Laradji and researchers at the Physics Laboratory of the Technical University of Helsinky to investigate the diffusion of liposomes (lipid vesicles) in confined geometries. See Faculty in the News for more information.

Structure of Interfaces and Nanoparticles
The performance of electrochemical sensors in biomedical applications depends crucially on the characteristics of the space charge layers formed on both sides of the interface with the sample as well as the transport and storage of charged and uncharged species at the interface. The electrical, mechanical, and other properties of nanoparticle composites likewise depend on the space charge layers near the surfaces of the component nanoparticles, with the interesting possibility that bulk electroneutrality exists nowhere inside the particles.

Our work is theoretical and computational. A theoretical baseline is provided by solutions of the Nernst-Planck Poisson equation governed by boundary conditions describing interfacial processes and possibly coupled to diffusion equations for neutral reactants or products. This system is well explored in one dimension but must be treated numerically for two- and three- dimensional geometries, coupled to elastic distortions, and corrected for discreteness of charge effects. In additional to mathematical modeling of space charge structures, we have capabilities for nonlinear least squares fitting and interpretation for impedance measurements made on experimental systems.

		Computational Biophysics
Biological Surfaces and Thin Films Laboratory Biomaterials Research Laboratory Nanoparticles in Polymers		Mohamed Laradji, PhD Donald Franceschetti, PhD The Computational Biophysics group is involved in many areas of computational and theoretical modeling and simulation. Below are just a few examples of ongoing projects. For more information, contact the researchers listed above. Diffusion in Confined Geometries The picture at the right shows a snapshot of a lipid vesicle formed of two types of lipids embeded in a three-dimensional solvent. The kinetics of the phase separation process is governed by the competition between the interfacial tension between the two lipids regions and bending rigidity of the lipid bilayer. Eventually a full phase separation is achieved. This snapshot is obtained from a large scale simulation of 1.5 million particles (lipids + solvent particles). The simulations use the method of Dissipative Particle Dynamics of a molecular model." Dr. Laradji has initiated a collaborative project between Dr. Laradji and researchers at the Physics Laboratory of the Technical University of Helsinky to investigate the diffusion of liposomes (lipid vesicles) in confined geometries. See Faculty in the News for more information. Structure of Interfaces and Nanoparticles The performance of electrochemical sensors in biomedical applications depends crucially on the characteristics of the space charge layers formed on both sides of the interface with the sample as well as the transport and storage of charged and uncharged species at the interface. The electrical, mechanical, and other properties of nanoparticle composites likewise depend on the space charge layers near the surfaces of the component nanoparticles, with the interesting possibility that bulk electroneutrality exists nowhere inside the particles. Our work is theoretical and computational. A theoretical baseline is provided by solutions of the Nernst-Planck Poisson equation governed by boundary conditions describing interfacial processes and possibly coupled to diffusion equations for neutral reactants or products. This system is well explored in one dimension but must be treated numerically for two- and three- dimensional geometries, coupled to elastic distortions, and corrected for discreteness of charge effects. In additional to mathematical modeling of space charge structures, we have capabilities for nonlinear least squares fitting and interpretation for impedance measurements made on experimental systems.
		Resources and Collaborations
		Computational Research on Materials Institute at the University of Memphis (CROMIUM) The Molecular Computing Group Technical University of Helsinki Center for Membrane Physics (Memphys)