The primary goal of our research is to investigate the thermodynamic, transport, and biophysical principles that underlie separation processes for biological macromolecules, and to exploit this improved understanding in order to develop novel separation methods.  One main area of work has involved studies of chromatography, which is widely used in the biotechnology industry for both analytical-scale and process-scale separations. 

        Chromatofocusing.  One recent area of work has involved investigations of the technique of chromatofocusing.  Our main goal is to overcome current limitations in both analytical and preparative applications of this technique.   In one particular project, computer-aided design methods are being developed to optimize the conditions so that stable gradients can be formed without using the polyampholyte buffers and proprietary weak-base column packings normally used for chromatofocusing.  Such systems are likely to greatly expand the range of applications possible for the technique, including to peptide separations, to high-speed, high-resolution, and high-sensitivity analytical separations performed using capillary columns, and to various process-scale systems, such as those using expanded beds. In a related project we are developing a novel hybrid chromatography method, which we have termed "displacerless" displacement chromatography that incorporates aspects of both chromatofocusing and displacement chromatography and that eliminates the need for a traditional displacer component for accomplishing displacement chromatography.

        Development and Characterization of Novel Chromatographic Column Packings.  Our work in this area involves both the characterization of novel types of column packings and the development of new characterization methods  based on theories of chromatography.  In one specific project, which is being conducted in collaboration with W.R. Grace, we are investigating a variety of novel silica-based column packings for use in protein chromatography.  Another project involves the investigation of slurry packing methods for conventional, microbore, and capillary HPLC columns with the goal of increasing the performance of these columns.   

         Methods for Proteome Analysis.   Novel versions of chromatography are being interfaced to a mass spectrometer to develop improved liquid chromatography - mass spectrometer (LC-MS) methods for protoeme analysis.  In one project high-resolution chromatofocusing performed using a micropellicular (nonporous particle) column packing, and used as a component of a two-dimensional chromatography method, is being interfaced to either ESI-MS or MALDI-TOF-MS to produce a technique that has potential as a replacement for standard two-dimensional polyacrylamide gel electrophoresis (2DE) for the routine characterization of protein molecular weight and isoelectric point.   In a related project we are investigating other uses of  high-throughput, multidimensional chromatography for proteome analysis. We are also investigating the use of chromatofocusing as a sample prefractionation method for increasing the dynamic range of narrow-pI-range 2DE gels.      

         Use of Green Fluorescent Protein (GFP) for Protein Purification Process Development.  Applications are being developed for the use of the flourescent protein GFP for purification process development.  In one application GFP or GFP fusion proteins are focused onto a retained stepwise pH transition and used for the visualization of viscous fingering and related flow irregularities inside a chromatographic column.

         Biomedical Applications of Chromatography.  Various applications of analytical chromatography in biomedical science are being investigated.  In one study, improved methods are being developed for the high-resolution detection of glycosylated variants of hemoglobin for use in diabetes detection and treatment monitoring.