The development and analytical applications of the glass nanopore electrode and the glass nanopore membrane.

摘要

This dissertation describes the development and analytical applications of glass-nanopore based chemical sensors, namely the glass nanopore electrode and the glass nanopore membrane. Chapter 1 starts with an overview of the applications of nanometer-size materials and structures in analytical chemistry, with an emphasis on the application of nanometer-size electrodes in electrochemistry and the fundamental aspects of the glass nanopore electrodes. An overview of applications of nanopore membranes in analytical chemistry is also presented.; Chapter 2 introduces the details of preparation and characterization of three electrochemical/chemical sensors: the glass-sealed Pt/Au nanodisk electrode, the glass nanopore electrode, and the glass nanopore membrane. A very sensitive continuity tester is introduced in the polishing process, which greatly improves the reproducibility in fabricating nanometer-size electrodes. Atomic force microscopy (AFM) and electrochemical voltammetry are used to characterize the geometry of the nanostructures. Chapter 3 describes the electrochemical characterization and finite-element simulations of the voltammetric response of the nanopore electrodes. The steady-state voltammetric response is fully characterized electrochemically and analytically. Chapter 4 describes an analytical application of the glass nanopore membrane for the detection of polystyrene nanoparticles using conical-shape glass nanopores. Our results show that nanoparticles can be detected using the glass nanopore membranes through the resistive-pulse sensing method. The current-pulses using conical-shape glass nanopores are triangular, and are one to two orders of magnitude shorter than the square-wave pulses using conventional cylindrical nanopores with similar pore radius and length. Finite-element simulations are performed to simulate the shape of current pulse and the transfer rate of nanoparticles as a function of the applied voltage. It is found that the simulated waveform qualitatively matches the recorded waveform, whereas the simulated transfer rates are ∼4X larger than the detected transfer rates. We explain those differences using the physical interactions between nanoparticles and the pore walls.