Chemical Engineering Seminar

Cellular Membrane Materials as Motors: Optical Methods to Characterize Nanoelectromechanical PropertiesProfessor Bahman Anvari
Department of Bioengineering
Rice UniversityThe ability of cellular membranes to perform useful work is often ignored because they are relatively delicate and under many conditions deform easily. Yet, the membranes of living cells are poised to utilize the intense electric fields (> 10 MV/m) generated by the electrochemical gradients across them. For example, the ability of membranes to generate electrically-induced force is demonstrated in cochlear outer hair cells (OHCs) that are capable of producing rapid (> 50 kHz) movements, known as electromotility, a process required for normal hearing.
Using a novel experimental approach that combines optical trapping with voltage-clamping and fluorescence imaging, we have demonstrated that native biological membranes are capable of electrically-induced pico-Newton level force generation over a broad range of electrical excitation frequency (> 3 kHz). This electromechanical force is: (1) enhanced in presence of a specialized transmembrane protein, prestin, found in the OHCs; (2) affected by the amplitude and polarity of the transmembrane electrical potential; and (3) diminished in the presence of a specific anionic amphipathic agent, salicylate.
Our long-term objectives are to understand the molecular basis of electromotility, and investigate how membrane-based electromechanical coupling can be modulated in a controlled manner through changes in membrane physical properties and membrane-protein interactions. Characterizing the nanoelectromechanical properties of plasma membranes has the potential to not only lead to a better understanding of the hearing process and development of therapeutics for specific types of hearing loss, but also has relevance to a broad range of biological processes where membranes harness the energy in the transmembrane electric field, and to the development of biological nano-electromechanical systems with diagnostics and therapeutic applications.Thursday, February 16, 2006
Seminar at 12:45 p.m.
OHE 122
Refreshments will be served after the seminar in HED Lobby
The Scientific Community is Cordially Invited

Location: Olin Hall of Engineering (OHE) - 122

Audiences: Everyone Is Invited

Contact: Petra Pearce