My research training is primarily in the area of laser spectroscopy. I have worked with both gas-phase and solution-phase systems using pump-probe techniques and microscopy. I have studied the behavior of individual molecules in the excited state using both experimental and theoretical approaches. I have also worked on biomedical applications of laser-scanning microscopy.
I am currently working on several different projects at SU. These projects are short-term and well-defined so that they can fit into a student's busy schedule. The common theme connecting all of these unique projects is “how do molecules interact and behave when excited?”
Students working on these projects gain valuable experience
with high-end instrumentation in the Chemistry Instrument Room and Laser Lab and the successful completion of a project (or a crucial part of a project) can lead to a national or regional conference presentation and/or a publication.
The Laser Lab: The Susquehanna University Laser Lab is located in NSC 308. The lab is equipped with a pulsed Nd:YAG laser and a continuous-wave Ar-ion laser. The experimental setups include a frequency-domain lifetime system, an inverted microscope that is used for photochemistry (cross-linking of of proteins and synthetic materials), imaging and fluorescence microscopy, along with various data acquisition and analysis equipment.
Future goals include Raman scattering and single-molecule spectroscopy.
Brief Description of Projects:
1. Cross-linking of proteins using a laser-coupled microscope. We are using a pulsed laser to excite various photoactivators that promote cross-linking of proteins. Cross-linked proteins structures have been 'fabricated' on the micron scale and we are in the process of studying the cross-linking process more closely and looking at the bioactivity of these structures.
2. Interaction of lanthanide ions, lanthanide chelates, transition metal complexes, porpjhyrins and nanoparticles with DNA. How do these systems promote the formation of certain types of DNA structures (quadruplex, triplet-repeat)? Can we use them to detect low concentrations of quadruplex structures? We are using fluorescence spectroscopy, excited-state lifetime measurements and Raman spectroscopy to answer these questions.
3. Fluorescence quenching of different proteins by metal complexes: we are interested in studying the effect of transition metals (Cr, Ni, Mo, Zn etc) on the spectroscopic properties of proteins: do they take away energy and photons from the excited state and thereby “quench” (decrease) the fluorescence intensity of the protein. We are comparing the effects of different metals as well as different ligands (hydrophobic and hydrophilic) attached to metals.
4. Effects of solvents on spectroscopic properties of aromatic systems (fluorenones, indoles). Again, another fluorescence experiment, this one being a collaboration with a faculty member at Bucknell, where we’re looking at the effect various solvents have on certain molecules.
5. Computational chemistry: We carry out quantum chemical calculations using Gaussian to find the most stable forms of compounds and complexes, both in the gas-phase and in solution. For example, we can compare the energy of a protein with and without a metal ion present. This will allow us to make predictions about the actual experiment and also compare theory to experiment.
Some of the calculations were
carried out as part of the project described in Research Interests #
My research students have presented their research at undergraduate poster sessions at various local, regional and national conferences including MARM (Middle Atlantic Regional Meeting of the ACS), ACS (American Chemical Society National Meeting), NCUR (National Conference for Undergraduate Research), State Capitol (Harrisburg, PA) and SU's Senior Scholar's Day.
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