The overall theme of our research is to develop programmable structures and advanced materials, and to understand their mechanics, thermodynamics, and kinetics. Our ideas for technological breakthroughs are often inspired by biological processes in nature. Our effort includes design and fabrication of DNA nanostructures via self-assembly, which are integrated with synthetic biomaterials (e.g., vesicles) and nanomaterials such as carbon nanotubes and transition metal dichalcogenides. These materials are used to develop novel devices with new levels of system control at the nanoscale. Characterization techniques include absorption, Raman, and photoluminescence spectroscopy ranging from UV to near-infrared, with an emphasis on single particle imaging. Additionally, atomic force microscopy and electrochemistry are methods commonly used in the lab. While we focus on fundamental nanoengineering, we aim to make transformative impacts in our society as well as scientific community.
Architectured materials exhibit negative Poisson’s ratios and enhanced mechanical properties compared with regular materials. Their auxetic properties emerge from periodic cellular structures. Most metamaterials are fabricated by top-down approaches and macroscopic with unit cells of microns or larger. We construct auxetic metastructures from DNA and study their mechanical properties and deformation behaviors toward general design principles for biomolecular metamaterials.
Synthetic cell-mimicking systems can serve as a platform to study fundamental biology or to develop novel biomedical applications. Like biological cells, synthetic biosystems can move, sense, compute, and interact. We demonstrate artificial cells with complex functions by engineering functional DNA components such that, for example, they can respond to environments and execute programmed behaviors including self-organization and coordinated migration.
Protein motors have evolved to perform specific tasks critical to the cell function such as intracellular trafficking. Inspired by the biological machines, we develop synthetic analogues from DNA. The DNA machines can actively convert chemical energy into mechanical translocation in a series of conformational changes. We study their thermodynamics and kinetics as well as multifunctionality to establish design rules for programmable, autonomous, high-speed nanomachines.
Two-dimensional (2D) van der Waals heterostructures from transition metal dichalcogenides (TMDs) show extraordinary properties that are distinct and different from those of bulk materials. For example, strong interlayer and intralayer excitons emerge from atomically thin layers. We study interfacial engineering that can control the properties of heterostructures as well as individual TMDs. Our work will help develop new materials for future electronics and energy applications.
See Selective Chemical Modulation of Interlayer Excitons in Atomically Thin Heterostructures and Understanding the Effects of Dielectric Property, Separation Distance, and Band Alignment on Interlayer Excitons in 2D Hybrid MoS2/WSe2 Heterostructures