Abstract

There has been much recent interest in using channel proteins as the basis of new chemical detection technologies, including molecular sensing and single-molecule DNA sequencing; these proteins are also important drug targets. Ion channel measurements are performed by incorporating proteins into lipid bilayer membranes; however, these 5 nm-thick membranes are fragile, short-lived, and labor-intensive to fabricate. These shortcomings greatly limit the use of ion channel proteins in engineered devices. We have developed two novel technologies that address these shortcomings: In the first, we have encapsulated lipid bilayer membranes within a hydrogel network. This encapsulation process, in which a hydrogel is polymerized in situ around a self-assembled lipid bilayer, results in membranes that are robust to mechanical perturbation and that last over ten times longer than the previous state of the art. Hydrogel-encapsulated membranes can support extended measurements of ion channel proteins at the single-molecule level, and have the potential to enable long-lived ion channel sensors in portable devices. Our second novel technology is a microfluidic system for automated membrane fabrication and measurement. This system controls and automates the process of membrane self-assembly through material-driven solvent extraction from a multiphase droplet flow. Ion channel proteins can be incorporated in these membranes and measured with single-molecule resolution. This on-demand bilayer fabrication technology can form the basis of membrane arrays for high throughput sensing for chemical detection as well as drug discovery and screening. These technologies provide two complementary pathways to the development of devices in which channel proteins serve as active nanoscale sensing elements.

URL:
http://chems.usc.edu/faculty_staff/noah-malmstadt.htm

Friday, December 1, 2006 Seminar at 11:00 a.m. HED 116 The Scientific Community is Cordially Invited to Attend.