Research Interests

DNA Nanotechnology

We are interested in programmed self-assembly of nucleic acids (DNA and RNA), or DNA nanotechnology. Nucleic acids are information-rich molecules. They have well-defined secondary structures (duplexes) and simple interaction rules (Watson-Crick base pairing). These chemical properties render nucleic acids to be excellent molecules for programmed self-assembly. Since 1982, a wide range of nanostructures have been constructed and find applications in biosensing, imaging, smart drug delivery, organizing chemical reactions, plasmonic devices etc. Our current research topics include:

         1. DNA/RNA self-assembly. A key question that we would like to address is: how can we prepare complicated DNA nanostructures simply from minimal numbers of unique component DNA/RNA strands? In this regards, we are extensively taking advantage of structure/sequence symmetries.

         2. Structural determination of biomacromolecules. The central idea is to organize biomacromolecules onto self-assembled DNA nanostructures to form highly symmetric biomacromolecule-DNA complexes, which can be readily characterized by X-ray crystallography or cryo-EM imaging.

         3. DNA-directed guest self-assembly. DNA nanostructures can serve as a platform to organize/integrate multi-functionalities (such as molecular recognition, catalysis, and light harvesting).

         3. DNA-based molecular lithography. We are developing methods to transfer DNA nanostructures into nanostructures of functional materials, e.g. silicone.

         4. DNA nanomachines. Conformational changes of DNA can be programmed to perform particular functions, e.g. transporting materials along prescribed paths.

         5. DNA-based nanomedicines. We are exploring using DNA nanostructures as platforms for sensitive disease diagnosis, bioimaging, and smart drug (small nucleic acid drugs in particular) delivery, and therapeutic devices.

         6. Interrogation of basic biological processes/interactions related to spatial-temporal controls. Among many biological problems of our interest, multivalency is particularly important. It is a common strategy in biological events, ranging from immune responses to cell interactions. DNA nanostructures provide a universal tool to organize ligands for studying multivalent interactions.

Major techniques in our group include:

DNA/RNA manipulation (synthesis, conjugation, purification, quantification, and amplification), imaging [fluorescence microscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), and cryogenic electron microscopy (cryoEM)], spectroscopy (UV-Vis and Fluorescence), soft lithography, X-ray diffraction, microfluidics, cell culture, and chemical synthesis.