Integrated Cancer Research Center Seminar Series

"Molecular Machines Kill Cells by Drilling Holes in the Lipid Bilayers"

James M. Tour, Ph.D.
T. T. and W. F. Chao Professor of Chemistry
Professor of Computer Science
Professor of Materials Science and NanoEngineering
Smalley-Curl Institute and the NanoCarbon Center
Rice University


Beyond the more common chemical delivery strategies, several physical techniques are used to open lipid bilayers of cellular membranes. These include electric and magnetic elds, temperature, ultrasound and light, to introduce compounds into cells, release molecular species from cells, or to selectively induce apoptosis or necrosis. It was not until recently that scientists started exploiting molecular motors and switches that can change their conformations in a controlled manner upon external stimuli, to produce useful work for biomedical applications. In this talk we show that nanomechanical action can be used to open cellular membranes by association of molecular motors with lipid bilayers, and then activating the motors with light. Using precisely designed molecular motors and complementary experimental protocols, nanomechanical action can (a) induce the diffusion of analytes out of synthetic vesicles, (b) enhance diffusion of traceable molecular machines into and within live cells, (c) induce necrosis, (d) introduce analytes into live cells, and (e) be selectively targeted to speci c live cell-surface recognition sites through nanomachines bearing short peptide addends. While this was initially demonstrated with UV light, other sources of light are being considered including visible, 2-photon near IR, and Cherenkov-emitted light for deep tissue use.