Advisor: Christine K. Payne, PhD (Georgia Institute of Technology)
Co-Advisor: Craig R. Forest, PhD (Georgia Institute of Technology)
Todd Sulchek, PhD (Georgia Institute of Technology)
Garrett B. Stanley, PhD (Georgia Institute of Technology)
Maysam Ghovanloo, PhD (Georgia Institute of Technology)
“Conductive Polymer Microwires for Single Cell Bioelectrical Stimulation”
The average human brain has over 80 billion neurons, but the number of cells responsible for brain dysfunctions such as Parkinson’s disease is unknown. Current electrodes used to treat brain disorders electrically stimulate ~200,000 cells simultaneously and often induce side effects such as blurred vision and headaches. Furthermore, rat studies have shown that the stimulation of a single neuron can affect behavior. A bioelectrode that is flexible and small enough to deliver targeted electrical stimulation to isolated cells in a 3-dimensional tissue matrix is needed to understand and treat only the defective neurons in dysfunctional brains.
The research presented here aimed to develop conductive polymer wires as flexible bioelectrodes for single cell stimulation. Polymer wires can be grown onto existing electrodes in situ with tunable dimensions and material properties. This work was the first to test these wires as single cell bioelectrodes. Conductive polymer wires were found to successfully stimulate individual cardiomyocytes in vitro. Patch clamping was used to directly measure changes in cell membrane potential in response to local field potentials generated by polymer wires. New characterization techniques were developed to obtain the electrochemical properties of individual polymer microstructures. Finally, a simulation model was built from experimental results to predict the electric field shape and magnitude for the development of future polymer and composite wire materials, shapes, and sizes. This work established the foundation for the next generation of flexible, single cell bioelectrodes.