Photonics Center Community Distinguished Lecture Seminar with Steven Chu, PhD

Abstract: The transport of molecular cargos in neuronal cells is analyzed in the context of new developments in statistical physics. Our development of very bright rare earth up-converting optical probes enabled the long-term single tracking of molecular cargos. These nanoparticles allowed individual molecular steps to be resolved at cellular ATP concentrations that led to a new, detailed quantitatively falsifiable chemo-mechanical model where two ATP molecules are hydrolyzed sequentially. A model of how this motor cleverly uses thermal fluctuations to produce move molecular cargos will be discussed. This model, which does not agree with the widely accepted model, provides detailed quantitatively falsifiable chemo-mechanical predictions that can be further tested. More recently, the tracking resolution has been improved to 1 μs time resolution and 0.12 nm spatial resolution using plasmonic particles, and a progress report of our single particle tracking experiments with this improved spatial and time resolution will be given. Finally, this motor’s is shown to operate in steady-state non-equilibrium that can be described with an “effective temperature” T_eff as high as 30 x 310K. An intuitive understanding of meaning of T_eff will be given.