ACT-SGER: Charge Exchange and Chemical Structure at Protein-Semiconductor Interfaces

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

This project addresses electronic properties of semiconductor interfaces with biological molecules with an aim toward improved sensors. Biological molecules exhibit charge transfer at semiconductor interfaces that change as the adsorbed molecules link to other biological species. Understanding and control of the bio/semiconductor interface along with its electronic, chemical, and biological activity may enable advances in biosensors for monitoring biological functions in vivo, detecting pathogens and other biologically active species. The goal of this project is to understand, optimize, and control these bioelectronic phenomena. Surface science, electronic, and biological techniques will be used to characterize protein-semiconductor interfaces on an atomic scale. Materials science and ultrahigh vacuum processing techniques will be used to control chemical activity and morphology of the surface and the resultant interface. Along with study of chemical and morphological conditions, research on preparation and deposition conditions of model biomolecules to obtain a range of charge transfer with the semiconductor and with biomolecules bound to its surface is included. It is anticipated that basic science understanding of biomolecular-semiconductor interfaces could catalyze a new avenue of research into studies of biological species interfaced to electronic materials. For example, an understanding of the systematics between the biomolecule's native charge state during deposition, the resultant charge exchange with silicon and its native oxide, and its subsequent change with further conjugation could provide design rules for creating biosensors with high biological specificity. Similarly, the understanding and control of charge transfer at biological material interfaces extends to electrical signal generation and propagation by nerve cells on artificial scaffolds, self-organization of proteins coating patterned substrates, and in-vivo immunoassay of specific biological material. Key specific goals of the project are correlation of charge exchange measured at the Si/SiO2 interface with the known charge properties of conjugated biomolecules or proteins, with the morphology of the Si/SiO2 surface layer, and with the protein's strength of bonding with this layer. This knowledge may have significant technological impact on the design of biological sensors if the use of an established technology-semiconductor transistors-can be extended with the design of biologically active and specific charge transfer sites. Success in this project is expected to lead to the implementation of this approach in devices of high commercial and security value. With high sensitivity and selectivity, such devices could advance the use of surface chemical and morphologic modification in venues such as in-vivo biomedical sensors, sensors for pathogenic organisms, environmental gas sensors, and for monitoring and protecting the nation's food supply. %%% The project addresses fundamental research issues associated with electronic/photonic and biological materials having technological relevance. An important feature of the project is the strong emphasis on education, with emphasis on integration of research and education. Students will be trained in a variety of modern electronic, processing, and surface science techniques, as well as in biomolecular engineering and characterization. The interdisciplinary training afforded by this project will help build a skilled workforce in rapidly developing bioengineering fields. This award is supported jointly by the NSF and the Intelligence Community. The Approaches to Combat Terrorism (ACT) Program in the Directorate for Mathematics and Physical Sciences supports new concepts in basic research and workforce development with the potential to contribute to national security.