A microscopic bit of matter in solution is in continuous motion. Pummelled at random by the solvent, it engages in a Brownian walk that will eventually take it far away from where we first started to observe it. At the nanoscale, even gravity is too weak to influence the trajectory of the object. Placing surfaces in the vicinity however puts new forces into play. By appropriately tailoring the geometry of the walls we are able to harness these intrinsic object-wall forces and manoeuvre our entity of interest into a desired spatial location and orientation in a fluid. Once there, the object levitates stably for long periods.
At my group we are pioneering the use of the "electrostatic fluidic trap" in order to realize new experiments in the spatial control, manipulation, and measurement of nanoscale matter in solution. Our primary focus is on biological molecules such as proteins and DNA; some experiments also involve inorganic entities displaying interesting photonic properties. Our research uses micro- and nanofluidic systems as the experimental platform, and relies on a combination of optical imaging and spectroscopy, nanofabrication, and numerical modeling and simulation.
Beyond spatial control of molecules, we have a strong interest in measurement - of molecular physical properties, dynamics and interactions. Molecular electrostatics has remained relatively unexplored terrain at the experimental level, and a new line of activity unfolding in our lab focuses on understanding the relationship between molecular electrical charge and 3D conformation. Having recently demonstrated how our unique "field-free" trap offers high-precision measurement of the effective electrical charge of a single molecule in solution, a major current goal is directed at using this novel approach in order to read out three-dimensional conformational changes or fluctuations in a single macromolecule in real time.
Besides potentially making their way into practical devices such as ultrasensitive and highly precise molecular sensors, possibly even memories and displays, our findings are continually pushing the envelope on control, manipulation and fundamental measurement of matter at the nanometer scale.