This work, by Assistant Professor Li Sun of the University of Minnesota-Twin Cities, focuses on single nanopores in metal membranes and is supported by the Analytical and Surface Chemistry Program. The nanopores are ion-conducting and contain a surface modifier which binds to an analyte ion selectively. The capture of an ion transiting the pore modulates the pore ionic conductivity which is the signal of interest. This approach has the advantage that analyte crossing the pore need not be capable of producing redox or spectrometric signals. Pore fabrication will be investigated using both electrochemical and self-assembled monolayer technology to control the pore structure. The nature of molecular transport through a pore will be studied using surface analytical techniques including surface enhanced Raman spectroscopy and electrochemical methods. Knowledge gained from these fundamental studies will be used to develop new detectors for chemical analysis, particularly of biochemicals. A major objective of this work is to fabricate structured pores of approximately small molecule dimensions in metal membranes for the purpose of studying the transport of molecules across such a pore. Fundamental study of the chemistry of ion binding to selective sites within the pore is useful because ion channels are an important and not yet fully understood mechanism for control of information flow across biological membranes. A second major goal of the project is to develop new types of detectors for chemical analysis which also utilize the ability of the active sites in the pore to selectively interact with ions of interest in the pore solution.
