We develop and study new nanomaterials for catalysis, signaling, and active matter. We are interested both in understanding how nanomaterials function, and in developing new and better ones. We also seek new ways to fabricate nanostructures, and novel ways to perform reactions.
Our ultimate goal is to introduce autonomous capabilities to nanomaterials, and create nanobots – nanoscale machines that operate independently, to travel within the body and treat disease and injuries; assemble complex structures; carefully control chemical synthesis to produce non-thermodynamic product distribution; or break down contaminants. To achieve this goal, we must first understand how various nanoscale components interact with one another, and impact each other’s performance.
We combine knowledge and techniques from all sub-fields of chemistry with inspiration from biological systems, and take a physical chemistry approach to analyzing the complex behaviors of dynamic, nanoscale systems. We currently focus on experimental work, but intend to introduce simulation studies in the future.
We currently focus on the following directions:
1. Nanoscale reaction control – metal nanoparticles (NPs) are excellent catalysts, but can we control their activity? What role do the nanoparticles’ stabilizing ligands play? What about their microenvironment? Can we engineer the surroudings of the particle to tune its activity? We seek to answer these questions, for both static and responsive structures.
Reaction-regulating nanoparticle. Catalyst A catalyzes R1→R2; switch B reacts with R2 to form the bulkier B’, restricting access to A
2. Surface-based chemical reaction networks – biological complexity arise from the interaction of multiple components, which react with one another, modulate one another, process and transmit information, and react to various signals. The synthetic analog, chemical reaction networks (CRNs) lack one crucial feature of biological circuits – spatial organization. CRNs mix all components in solutions, whereas biological circuits carefully separate components into different compartments and surfaces, and tightly regulate their interaction. We will create surface-based CRNs, with different network components placed in carefully designed patterns, to control their ability to interact with one another. Furthermore, the networks will use chemical signals to transmit signals, akin to nerve impluses. To facilitate this project, we are developing more capable photopatterning methods.
A chemical signal propagates along a surface using an autocatalytic reaction
3. Non-equilibrium transport – accurate nanoscale control requires transporting nanobots and cargo. Biological systems use asymmetric structures and potentials to produce transport, using a ratchet mechanism. Synthetic ratchets can transport particles ranging from micron-scale beads to individual electrons, and are a fascinatingly rich and complex field of study. We develop new techniques to explore these systems, and discover how to use them for applications such as energy harvesting and particle sorting.
A flashing ratchet – an asymmetric potential, oscillated at the right frequency, can transport particles, even though there is no overall bias