The research in our group focuses on computational macromolecular science, materials design and self-assembly. We use multiscale modeling and simulation methods as well as theoretical analysis to explore the basic science and the fundamental principles in the interdisciplines covering the fields of polymer, nanoscience, biomacromolecules and biomembrane. The research topics include the conformational behaviors and interactions of polyelectrolytes with various molecular architectures, the phase transition kinetics and mechanisms of polymer blends and copolymers, and the hierarchical structures formed by the self-assembly of nanoparticles in polymer systems. The interactions of some functional macromolecules, such as dendrimers and graphene-family materials, with the lipid bilayer membrane have also been explored by using mesoscale simulations and theoretical analysis. Two main research directions are introduced in more detail as follow.

1. Rational self-assembly and responsive matter in systems containing anisotropic nano building blocks.

In recent years, the request of next generation materials has driven material design into the ability to reversibly adapt to their environment and possess a wide range of responses. Simultaneously, two powerful design concepts: responsive matter and rational self-assembly emerge and play considerable role in this quickly developing area. The promising concept of responsive matter requires that intrinsic building blocks be able to reconfigure from one structure to another. For the concept of rational self-assembly, the building blocks should be carefully chosen and constructed in order to realize a high level of direction and control. A unique and emerging type of such building blocks are “patchy nanoparticles”, i.e, the nanoparticles decorated with specific, anisotropic surface patterns of attractive and repulsive interactions. Through a unique design with respect to particle size and shape as well as the number and position of the “patches”, these particles can be successfully directed to self-organize into complex superstructures. In this topic, we aim to use computer simulation method to design "Reconfigurable Nanoparticles" on the basis of static patchy nanoparticles. The self-assembled structures of tethered polymer chains on the nanoparticle surface and the hierarchically ordered structures formed through rational self-assembly of these tethered nanoparticles in polymer matric will be explored by using a hybrid model developed by us. Furthermore, the external fields will be induced into these systems to investigate the responses of these nanocomposites in the presence of various environments, from their multiscale structures to the macroscopic properties. The study could provide theoretical guidelines for the design of functional nanocomposites with responsive properties and precisely controllable topologies in a dynamical manner, e.g., reconfigurable, self-healing and smart materials, and might demonstrate significantly advancement and intuitive framework for the research of this important topic.

2. The transmembrane transport of functional macromolecules across cell membrane.

Understanding the interactions of nanoparticles with biological membranes is of fundamental importance in determining their potential application as drug delivery vehicles and therapeutic agents. As a framework in multifunctional nanodevices, dendrimers are particularly useful in the development of targeted chemotherapeutic agents. To understand the dynamical process and mechanisms of the transmembrane transport of dendrimers however requires direct measurements in a single cell and is thereby very difficult and more challenging. Tailored computer simulations offer a unique approach to address these unresolved issues through identifying and separating individual contributions to the phenomenon. In this topic, the dynamical process and mechanisms during the internalization of dendrimers across a lipid bilayer membrane are investigated by employing systematically mesoscopic simulations and theoretical analysis.

The other particle concerned by us in this topic is graphene-family materials. The remarkable physical properties provide graphene with great opportunities for various biomedical applications including drug delivery, cancer therapies and biosensors. The potential toxicity of this new nanomaterial motivates the research and evaluation of its biological interactions. One of the important biological interactions pertinent to graphene is also with cell membrane. The interaction between graphene and cell membrane raises a fundamental question as to the mechanisms of the cellular internalization of graphene-family materials. However, how graphene with typically two-dimensional (2D) geometry interacts with cell membrane remains poorly understood. In this topic, we thereby seek to address the pathway and mechanisms of the translocation of graphene and its derivants across cell membrane and the effects of the physicochemical properties of these materials on this process through computer simulations and theoretical analysis.