Our research interests lie in the areas of experimental soft matter and nanoscale systems. Our current aim is to exploit a unique combination of colloids, microfluidics, solid-state nanopores, and DNA nanotechnology to understand fluctuations and transport of materials in driven, out-of-equilibrium systems. Working with this range of systems allows us to probe phenomena from the single particle to continuum limit and to identify universal physical behaviour across different length and time scales. Understanding these processes is important in a wide variety of different scenarios, from understanding biological transport to improving state-of-the-art molecular sensing and DNA sequencing devices. More fundamentally, elucidating the statistical mechanics of non-equilibrium systems represents a significant challenge and we collaborate closely with theory and computational groups working in this area.
Understanding ionic transport in solid-state nanopores
Resistive pulse sensing with nanopores is a versatile single molecule sensing technique, with applications ranging from DNA sequencing to digital data storage. The basic operating premise is to analyse transient changes in the ionic current driven through a nanoscale pore as macromolecules such as DNA move through it. As such, dynamic signatures and fluctuations of an ionic current contain significant information. Our aim is to develop approaches to decode this information to achieve a fundamental understanding of transport in these nanoscale systems and engineer methods to improve their sensing characteristics. For example, we have recently shown that adding an adsorbing polymer to the system introduces non-trivial noise characteristics, which when carefully analysed yield information on underlying adsorption potentials. In the future, we intend to functionalise nanopores with DNA origami, allowing us to achieve unprecedented control over nanoscale transport processes.
Microfluidic transport of colloidal fluids
Transport through confining geometries is governed by a complex interplay of factors, including the channel geometry, driving force, interparticle interactions and specific interactions between particles and channel. The ability to directly observe the dynamics of colloidal particles in systems where we can control and tune all of these parameters means that they are ideally placed for unravelling this interplay. To achieve this, we combine microfluidic techniques with holographic optical tweezers to unambiguously understand molecular transport phenomena in arbitrary potential landscapes. Recent highlights include exploring the effect of system geometry on particle capture from the bulk in porous media and establishing methods to detect molecular intermediates along a reaction coordinate. Excitingly, we have shown that analysis methods developed in our mesoscale experiments can be applied to single molecule experiments such as DNA folding or transport through membrane pores, and we are working with groups in this area to help further elucidate their findings
