Research Interests

Coarse-grained modeling of biological and biomimetic fluid membranes

In this study, we present a one-particle-thick fluid membrane model, where each particle represents a cluster of lipid molecules. The model features an inter-particle pair potential with the interaction strength weighed by the relative particle orientations. With the anisotropic pair potential, particles can robustly self-assemble into fluid membranes with experimentally relevant properties. The model has been used to the study of dynamic vesicle shape transformation, lipid domain interaction, etc.

Multiscale Modeling of Deformation Morphologies of multi-walled carbon nanotubes and Graphene Sheets

We employ a quasi-continuum method based on finite crystal elasticity theory for curved crystalline monolayer to simulate the mechanical responses of thick multi-walled carbon nanotubes under different loading conditions. We have observed an enriched morphologies of deformed MWCNTs distinctly different from those of SWCNTs.

Multi-scale simulation of DNA-Carbon Nanotube Complexes

We developed a coarse-grained model for the study of the energetics and morphologies of DNA-carbon nanotube (DNA-CNT) complexes in aqueous environment. The coarse-grained model is computationally efficient for large-scale simulations, yet sufficiently detailed to capture the essential dynamics at atomic scale. The structural properties and energetics of several different DNA-CNT assemblies are studied using this coarse-grained model with Langevin dynamics.

Protein-mediated endocytosis of nanoparticles

Animal viruses invade their hosts in a rather controlled fashion, a process known as endocytosis. Biological studies revealed that virus invasion is both type selective: i.e., certain viruses are engulfed but not the others, as well as size selective, i.e., 50nm viruses are engulfed preferably but not 100nm ones. This fascinating adhesion-driven process makes one wonder: what are the fundamental mechanisms that govern specificities of endocytosis?

We have developed a thermodynamic model with which we reveal that, unlike the adhesion between two inanimate objects, the adhesion strength between an NP and a living cell is a non-local, variable quantity that depends on not only the particle size and the ligand density, but also the receptor density that is actively regulated by the cell. The cellular uptake depends interrelatedly on the particle size and ligand density, featuring a two-dimensional phase diagram in the particle size and ligand density space. The variable adhesion strength specifies a lower and an upper phase boundary beyond which the cellular uptake vanishes. The design principles of the NPs obtained from our studies are validated by comparisons to the characteristics of viruses and existing experimental data. Our findings are not only important for understanding the biological behaviors and evolutionary design of viruses, but also for engineering NP-based therapeutic and diagnostic agents.