Event
MSE Seminar - Prof. David C. Martin, Karl W. and Renate Boer Chair, University of Delaware
Friday, September 18, 2009
1:00 p.m.
Room 2108, Chemical and Nuclear Engineering Bldg.
Annette Mateus
301 405 5207
amateus@umd.edu
"Soft and Fuzzy Conjugated Polymers for Interfacing Electronic Biomedical Devices with Living Tissue"
Our laboratory has been developing materials for interfacing electronically active, hard, chemically inert, biomedical devices with ionically active, soft, wet, living tissue. These materials include conducting polymers that can be externally stimulated to release drugs at the electrode-tissue interface. These materials dramatically reduce the impedance of the interface, and make it possible to tailor the chemistry of the surface, improving the performance of both recording and stimulating devices. Examples include cochlear implants, microfabricated cortical electrodes, pacemakers, glucose sensors, and peripheral nerve conduits for next generation total limb prostheses.
We use chemical and electrochemical polymerization to deposit controlled amounts of conducting polymers such as functionalized thiophenes including poly(3,4-ethylenedioxythiophene) (PEDOT). We also are investigating natural conjugated polymers including melanin derivatives. We measure electrical properties by impedance spectroscopy and cyclic voltammetry. We characterize morphology using optical microscopy, electron microscopy, and X-ray diffraction.
The impedance of conducting polymer coated electrodes is typically decreased by 2-3 orders of magnitude from the bare metal. Neurotrophic factors and anti-inflammatory agents (DEX) can be precisely delivered at the electrode surface, and remain biologically active. Enzymes can be incorporated into the coatings, providing chemical sensing capabilities. Novel melanin derivatives show different colors than found in nature, and are electrochromic. Hybrid conducting polymer / biomolecule coatings provide new functionality that create opportunities for significantly improving and tailoring the specific performance of a wide variety of bionic devices.
Our research has been supported in part by the NIH, the NSF, and the US Army Research Office (MURI program). DCM is a founder and Chief Scientific Officer for Biotectix, a University of Michigan spin-off company working to commercialize conducting polymer coatings for certain biomedical device applications.
