“Development of a Multiscale Model in Micro/Nano Electrokinetic Transport and Vascular
Targeted Drug Delivery Using Nanocarriers”
Dr. Jin Liu, University of Pennsylvania
This talk will contain three topics: 1) A hybrid multiscale model has been developed to simulate simple micro/nano fluidics. This model was based on spatial “domain decomposition” and “constrained dynamics” in which molecular dynamics was used in small crucial regions, and continuum fluid dynamics was used in bulk regions. The two descriptions were matched in an overlap region by constraining the molecules’ dynamics. After validation, the mode has been successfully implemented to study cavity flows. 2) A highly efficient molecular dynamics algorithm has been developed for micro/nano electrokinetic transport. The long-range Coulomb interactions were calculated using the particle-particle particle-mesh (PPPM) approach. The Poisson equation for electrostatic potential was solved in physical space using multigrid technique. This algorithm was implemented to study the electroosmotic flow in rough nanochannels and electrowetting on dielectric (EWOD). For the first time we were able to provide a mechanism of contact angle saturation based on molecular simulations. 3) A computational protocol based on the Metropolis Monte Carlo method and the weighted histogram analysis method (WHAM) has been proposed to calculate the absolute binding free energy between functionalized nanocarriers (NCs) and endothelial cell (EC) surfaces. Based on the free energy profiles, we were able to compute the binding affinities of NCs and investigate the effects from a broad range of parameters. Excellent agreements were obtained between our model predictions and measurements from in vitro, in vivo and atomic force microscopy experiments, implying the power of our model in design and optimization of functionalized NCs in targeted vascular drug delivery. The possibility of applying the multiscale model in 1) to problems in 2) and 3) will be discussed.
Jin Liu received his BS in mechanical engineering from the University of Science and Technology of China in 2001. He received his MS and PhD in mechanical engineering from the University of Michigan, Ann Arbor in 2003 and Johns Hopkins University in 2008, respectively. He has been a postdoc in the Department of Bioengineering at the University of Pennsylvania since 2009. His research interests focus on computational fluid dynamics, micro- and nanofluidics, electrokinetic transport, bio-fluidics, membrane dynamics and multiscale modeling.