Albena Ivanisevic
North Carolina State University

Development of Gallium Nitride Based Interfaces Using Surface Functionalization Techniques and Characterization

Location: EB1 Room 1011

Friday, September 26th 2014 - 11:00 am

One of the challenges associated with making implantable devices with long term functionality can be solved if one can find an interface material that not only matched the mechanical and electrical properties requirements but can also be tailored to reduce or eliminate foreign body response. There is a need for an interface that will simultaneously probe chemical and electrical mechanisms associated with neuronal function. We have started to use gallium nitride (GaN) to fabricate such a biointerface. Limited evidence suggests that GaN is an ideal material for this purpose. Advantages of GaN include a wide bandgap of 3.4 eV, availability of Ga bonds for covalent surface modifications, chemical stability, and low electrical drift of GaN biosensors in ionic solutions. Recently we conducted studies to examine the biocompatibility and toxicity of this material after chemical functionalization which can significantly increase its utility. Subsequently we used InGaN with different topographical and chemical gradients to fabricate biomolecular gradients with different adhesion characteristics. We have tested the utility of the interface in physiologically relevant solution conditions. The morphological, mechanical and chemical characteristics of the interface will be discussed based on recent analysis with microscopy and spectroscopy techniques. Cell studies data confirms that the tailored surfaces are suitable as biointerfaces to probe neuronal function and behavior. The last portion of the talk will focus on recent work centered on GaN surfaces with different polarities and the ability to enhance the semiconductor properties using in situ chemical functionalization during etching as well functionalization of GaN based devices.

North Carolina State University