Sequence-Controlled Polymerization of "Click" Nucleic Acids (CNAs)
Researchers are only beginning to realize the potential of DNA for a wide variety of applications that extend beyond the therapeutic and diagnostic realms. DNA can be used to create nanoscale structures, assemblies, and devices, in addition to many other applications. An efficient and cost-effective method of attaining sequence control in synthetic polymers is considered a "holy grail" within modern polymer science research. Our group is exploring new techniques to synthesize nucleic acids with a "clickable" backbone, using easily accessible and rapid thiol-X "click" chemistry to create the DNA backbone.
"Click" Reactions for Polymer Networks
The "click" chemistry paradigm, introduced by Kolb, Sharpless, and Finn in 2001, is a collection of reactions characterized by high yield, mild reaction conditions, orthogonality, and fast kinetics. In recent years, click chemistry has proven to be highly useful in the field of materials science, particularly in creating tunable step-growth networks. Our group has focused on creating photopolymerizable polymer networks using the thiol-X family of reactions and the Huigsen azide-alkyne cycloaddition reaction to create new and unique functional polymeric materials, including resins for photopatterning and micro- and nano-particle synthesis.
Covalent Adaptable Polymer Networks
Typically, crosslinked polymer networks are characterized as thermosets, meaning that once they are polymerized into a gel, they are "set" and cannot be reprocessed or recycled. Our group is studying a variety of chemistries that bridge the gap between the processability of thermoplastics and the many desirable properties (such as mechanical strength or solvent resistance) of crosslinked polymers. In covalent adaptable networks (CANs), specialized functionalities along the backbone of the polymer allow reshuffling of covalent bonds, usually in response to an external stimulus. Examples of techniques we have worked with include photo-induced reversible addition fragmentation chain-transfer (RAFT) and thermally reversible Diels-Alder reactions. We aim to further the fundamental understanding of these unique materials and expand on their many interesting new uses.
Novel Dental Materials
In addition to the applications of photopolymerized systems, additional projects are pursued with the goal of novel applications and improved understanding and analysis of currently available systems. These systems are being developed to provide new avenues for research and improved testing and predictive methods to be employed for both academic and industrial research.
Photoinduced Synthetic Vesicles for Artificial Cells
Double-walled vesicles comprised of two-tailed photopholipids are ubiquitous in nature and are vital to the most basic of biological processes. As part of a collaborative effort with groups from UC San Diego and Harvard, our group is working to make controllable and synthetically-accessible precursor molecules that can self-assemble or disassemble upon irradiation with visible-wavelength light. We are also exploring a variety of other manipulations of phospholipid precursors to dial-in additional functionalities within the artificial membranes.