We bring dynamic functionality to nanoscale systems. The nanotechnology field has developed an enormous array of nanoscale components, such as metal and semiconductor nanoparticles, supramolecular assemblies, and molecular switches. We combine new and existing components in thoughtful ways to produce responsive, “living” systems, which sense their environment, analyze it, and regulate their activity accordingly.
Our ultimate goal, currently in the realm of science fiction, is to create autonomous nanoscale robots, capable of such feats as traveling within the body and treating disease and injuries; assembling complex structures; carefully controlling chemical synthesis to produce non-thermodynamic product distribution; and breaking down contaminants.
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 employ both experiments and simulations, iteratively using one to guide the other.
We currently focus on the following directions:
1. Nanoscale reaction control – autonomous nanobots will need to regulate reactions in response to local conditions (feedback), or incoming signals from sensors and other nanobots. Current approaches to reaction control focus on operator-level measurement and intervention, and are impractical for smaller scales. We use biologically-inspired approaches to control and regulate reactions directly at the nanoscale.
Reaction-regulating nanoparticle. Catalyst A catalyzes 𝑹𝟏→𝑹𝟐; switch B reacts with 𝑹𝟐 to form the bulkier B’, restricting access to A
2. Communication via chemical signals – a central challenge in building autonomous systems is the transmission of information to the systems and between them. Transducing signals between chemical and electrical forms is impractical at the smallest scales. We use autocatalytic reactions to enable the transfer and processing of information directly as chemical signals, which are then used to control chemical reactions.
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