Scientific Research

Overview of Research Interests

Current and Recent Research Projects

1. Mineral Growth on Template Surfaces
2. Environmental Chemistry
3. Surface Chemistry: Thiols on Gold
4. Fiber Optic Biosensors
5. Membrane Potential Probes

1. Mineral Growth on Template Surfaces
The growth of many natural materials depends on crystallization initiation at a template, whose structure determines the final form of the material. We are using that concept to construct ultrathin crystalline materials. The materials are then used in studies of the durability of the material in corrosive solutions as well as the effectiveness of protective additives. These microscopic layer systems are studied using surface plasmon resonance spectroscopy.

2. Environmental Chemistry
Analytical chemistry is often applied to environmental science. My research interests include both fundamental research (new analytical methods) and applied research (new applications of existing analytical methods). The specific applied research project is environmental analysis.

Roanoke College is located in the Roanoke Valley in southwestern Virginia. The watershed is the upper Roanoke River basin. My research efforts have primarily involved water analyses in this watershed. Both inorganic and organic chemicals are analyzed, using a variety of standard methods. Most inorganic analysis projects have been centered on the question of relating geology and water composition. These projects have typically involved chemometric analysis to determine relationships between variables. My organic research projects involve determination of organic pollutants, e.g. pesticides.

3. Surface Chemistry: Thiols on Gold
A wide range of applications are on the horizon for molecular engineered materials such as nanometer thin films on surfaces. Highly ordered molecular assemblies are being fabricated and used as new materials for optical electronics, chemical sensors, and semiconductor devices. These systems are also used as models for adhesion, friction, and molecular adhesion. In each of these cases, a recurring theme is the inability to manufacture sizeable films one molecule thick, free of defects. Films containing defects often fail to perform the desired function. In this project my students have studied photoinduced or thermal annealing, in which the film is heated and molecules are somewhat free to move around in two dimensions. A number of studies have shown that film perfection is locally improved by annealing, but that the total defect area is unchanged on a macroscopic level. Projects have involved preparing films, performing various types of annealing, and analyzing the film perfection using cyclic voltammetry.

4. Fiber Optic Biosensors
In this project, biochemistry is combined with optical spectroscopy and surface chemistry. We have constructed and tested fiber optic biosensors. In these devices, the analytical selectivity is provided by a biological molecule such as an enzyme or an antibody. These biological recognition elements are immobilized on the surface of the fiber optic in a gel. The sensor is typically used to detect a small molecule which interacts with the biomolecule, using either absorption or emission of light as the readout. We have explored several types of gels and several types of biomolecules.

5. Membrane Potential Probes
Optical spectroscopy and surface chemistry have been the common features of my research activities for many years. In this project, biochemical membranes are studied. We measure membrane potentials using fluorescent probe molecules.

Figure from Molecular Probes web site: http://www.probes.com