1. Multiscale Modeling of Soft Matter
Liquids, polymers, gels, foams and a number of biological materials are soft materials, which can be easily deformed by thermal stress or thermal fluctuations. Predominant physical behaviors of these soft materials occur at energy scale comparable with room temperature thermal energy. These behaviors cannot be, or are not easily, directly predicted from its atomic or molecular constituents. This is because the soft materials are always self-assemble into mesoscopic structures, which are much larger than the microscopic scale (the scale of atoms and molecules), and yet much smaller than the macroscopic (overall) scale of these materials. Especially, the mechanical and physical properties of soft materials originate from the interplay of phenomena at different spatial and temporal scales. Simultaneously considering these behaviors at different scales is a forbidden challenge, even with the state-of-the-art supercomputer. As such, it is necessary to adopt multiscale techniques when dealing with soft materials in order to account for all important mechanisms.
2. Nanoparticle-mediated drug delivery
The expansion of nanotechnology over the past two decades has led to paradigm shift in drug delivery. For most of the history of chemical therapeutics, delivery was non-specific and the single controllable parameter was concentration. Although targeting of specific pathways through drug design was first introduced in the 1950s , the control over molecular properties afforded by advances in nanotechnology has ushered in a new era in drug delivery. Whereas early targeting strategies relied on chemical changes to individual molecules, it is now possible to synthesize complex macromolecular assemblies to serve as drug delivery platforms. The assemblies can be constructed from an ever-growing assortment of nanomaterial building blocks including lipid vesicles, block copolymers, gold nanoparticles, numerous forms of carbon-based nanoparticles, DNA, and hybrid platforms. The basic structures can then be functionalized to promote binding to specific molecular markers. Thus, these different building blocks serve as delivery vehicles, when binding to drugs/genes, to deliver the drug/gene molecules into specific diseased tissue or cell. Different combinations of these building blocks allow, for the first time, researchers to control the size, shape, and surface chemistry of delivery vehicles to obtain maximal therapeutic benefit at minimal harm to the patient. Although researchers now have a greatly expanded set of knobs to turn when designing nanoparticles (NPs), it is generally not clear how a change to a specific vehicle feature will alter the effectiveness of a drug, hence design of novel drug carriers require extensive and costly parametric studies that are generally specific to the system upon which the experiments were performed. Theoretical and computational modeling of the delivery process can greatly reduce the need for physical experiments and provide general design principles to expedite the design process.