Dr. Bret Flanders

Oklahoma State University

The Development of Nanomaterials for Electrophysiological Applications

Tuesday, March 11, 2008

4:00 p.m.

Cardwell 102

Harnessing natural pattern formation mechanisms to fabricate small-scale devices is a potentially efficient way for single research-labs to produce high precision instrumentation for customized experimental needs.  To this end, our group studies dendritic solidification, the diffusion-limited process that is responsible for snowflake-formation.  Most previous work on this classic topic has focused on stationary dendritic solidification, where the diffusive field is described by the stationary form of the diffusion equation.  We have found that a key step to controlling dendritic solidification is to work with non-stationary processes, where the diffusive field is described by the time-dependent form of the diffusion equation.  In so doing, we have developed the Directed Electrochemical Nanowire Assembly (DENA) technique, a single-step approach to fabricating conducting nanowires and interconnecting them with external circuitry.  These wires grow along user-selected paths; their diameter may be tuned from the microscale down to the nanoscale; they are composable of several different types of metal as well as conducting polymer; and the metallic wires grow as near single crystals.  We are currently working out the methodology for using DENA to grow wires between on-chip electrodes and living cells that are cultured onto the electrode array; voltage-stimuli might then be delivered to user-selected sites on their membranes.  Cells receive information from their environment through localized modulations to their membrane potentials, so this new approach to stimulating the cells could lead to interesting high resolution studies of cell signaling.  A major challenge to any electrophysiological technique is that the wire-cell contacts be made in a reproducible and biocompatible manner.  Working with Dictyostelium cells, we have developed an approach where the cell finds the wire and chooses for itself how to make contact.  This remarkable behavior circumvents the potentially difficult task of the user adequately contacting the cell. Further progress on our development of this technique will be presented.