Research

Dr. Abul Hussam: I have been involved in the development electroanalytical techniques for the study of toxic species in the environment. We are particularly interested in the chemistry of arsenic in groundwater and the development of inexpensive arsenic filters.

First, we have developed a field technique to measure parts-per-billion level of arsenic species in groundwater. Second, we have devised a simple method to purify groundwater from toxic arsenic species. More than 10,000 such filters are in use in Bangladesh and continue to provide more than a Billion liter of clean drinking water.

In addition, we are actively engaged in the development of hardware and virtual software for electroanalytical engines (reagent generator and sensor) to be used with ‘lab-on-chip’ platform. We have also extended the use of electrochemical techniques to understand the diffusion behavior and electron transfer kinetics of lipophilic redox species in organized media such as micelles and microemulsions.

To complement these studies we have built a high precision headspace gas chromatograph to study the partition behavior of volatile species in complex micelles and microemulsions.

Dr. John Schreifels: My laboratory works on problems associated with the solid – gas interface. We study molecular events occurring in the top few atom layers of solid surfaces (thickness levels of about 1/10000 the thickness of a human hair).

Recently, we studied the interaction of fuel additives with stainless steel surfaces. Certain compounds (called metal deactivators, MDA) are added to bulk fuel to eliminate fuel degradation during long term storage under ambient conditions. It turns out that fuels also form dark thick deposits on injectors of jet engines during operation. The temperature in the injector is much higher, which means the deposition rate is much higher than in the bulk fuel. These deposits can cause catastrophic failure of the engine.

The presence of MDA can reduce this effect. We studied the fundamental interactions of the compound with stainless steel in our instrument under ultra – high –vacuum conditions. The vacuum insured that we were studying only the interaction of the compound with the stainless steel surface. We found that the compound broke into smaller fragments upon initial exposure of the surface to the compound.

There were several new compounds generated in addition to the original compound that might have been the cause of the reduced deposition of residues on the surface. In fact because of the temperature at which each of these compounds desorb, from the surface we believe the new compounds may very well be responsible for the reduced rate of deposition.

Using the insights from this study, we will continue to deposit other compounds with chemical structures similar to the compounds detected on the surface to try to understand how to produce an improved effect. Additionally, we are studying the adsorption of compounds that are used to reduce the extent of corrosion.

Finally, our studies have involved metallic surfaces and how they interact with compounds to produce new compounds; these metal surfaces are often called catalysts and are used extensively in the chemical industry.

Dr. Yun Yu: Our laboratory focuses on the nanoscale electrochemistry of low–dimensional materials. We aim to understand and tailor electrocatalytic and photocatalytic reactions at plasmonic nanoparticles and layered van der Waals (vdW) materials. We leverage the capability of scanning electrochemical microscopy to obtain unique insights into the reaction kinetics and structure–activity relationships of the probed material.

With the knowledge gained from nanoelectrochemistry, we explore strategies to design complex material platforms that integrate metallic nanoparticles and 2D semiconducting layers to address the challenges in energy conversion chemistry. We currently work on (1) Electrochemical mapping of vdW heterostructures comprised of a series of 2D transition metal dichalcogenides (TMD). (2) Tailoring the selectivity of molecular electrocatalysis via vdW substrate engineering. (3) Manipulating plasmonic hot carrier energies with semiconductor layers. (4) Tuning the geometric effects of plasmonic/2D TMD heterostructure on its photocatalytic activity.

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Dr. Barney Bishop
“In my laboratory, we are interested in applying peptide/protein engineering principles to investigate biomolecules and their function. The rampant increase in the incidence of multi-drug resistant bacteria and the threat of bioterrorism necessitate new approaches to preventing and treating infection.

Higher organisms produce a complex host of molecules that they use to combat infection and invading microbes. In these defensive mechanisms, peptides and proteins consistently stand out as critical elements. Therefore, we are interested in studying the biophysical properties of these molecules and the varied antimicrobial mechanisms employed by them.

As a model system, we are looking at the defensin family of peptides, whose members demonstrate antimicrobial activity against a broad spectrum of pathogens including bacteria, fungi and viruses. We believe that such studies will provide valuable insights into strategies for combating bacterial and viral infections, and we intend use this information in the design of novel therapeutic agents and biomaterials.”

Dr. Robin Couch
The Couch lab is researching several aspects of developments of MEP pathway inhibitor antibiotics, small molecule metabolomics, biosensor/electronic nose, and chemoprevention of Alzheimer’s disease.

The increasing prevalence of antibiotic resistant strains emphasizes the need for continued development of new antibiotics with novel mechanism of action. Many human pathogens exclusively use the methylerythritol phosphate (MEP) pathway, making it an excellent target. To facilitate MEP pathway inhibitor development, my lab has cloned, expressed, and enzymatically characterized several MEP pathway enzymes. We are iteratively deriving structure-activity relationships and performing mechanism of inhibition assays to guide the development of rationally designed synthetic inhibitors of these enzymes.

We are also using state-of-the-art metabolomics techniques to evaluate small molecule metabolites present in biological samples, including feces. We are currently using both GC-MS and LC-MS in our analyses to examine fecal volatile organic compounds (VOCs). We discovered that the current technologies were inadequate to facilitate a proper headspace solid phase microextraction-based (hSPME) metabolomics analysis of biological samples. We developed and patented a device that enables these analyses, and coined the term “simulti-hSPME” to describe our optimal process of using multiple sorbent types to simultaneously extract VOCs of diverse chemistries from a sample. We are also using our newly developed simulti-hSPME for the rapid and minimally invasive detection of biothreat-relevant microbes (“electronic nose”).

We are applying our small molecule and protein expertise to determine the signal transduction mechanism underlying the ability of select small molecules to induce nerve growth factor release from glial cells. Nerve growth factor keeps neurons alive, and thus has promise for the chemoprevention of Alzheimer’s Disease. Using cultured human glial cells, we have utilized reverse phase protein microarrays to generate temporal maps of signal transduction protein activation, and we are now validating the involvement of these proteins/pathways using pathway specific agonists and antagonists.

Dr. Lee Solomon
Dr. Solomon joined Mason in June 2019 as an Assistant Professor of Biochemistry. His research lab will be on the Science & Tech campus (Manassas, VA). His work centers on using rational-design methodologies to understand natural functions and create proteins and materials, which will allow for the creation of new medicines and energy technologies. Dr. Solomon’s research lab will focus on three primary areas: (1) stimulated structural and morphological changes, (2) protein interactions, and (3) catalytic chemistry.

Dr. Liana Chafran
My research focuses on the synthesis and chemical modification of biopolymers and biomaterials through homogeneous and heterogeneous catalysis to obtain smart biomaterials, whose chemical, physical, and biochemical properties can be changed in response to an external stimulus such as temperature, pH, light, or contact with biomolecules (proteins, enzymes, DNA, or RNA).

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Dr. Gregory Foster: “Students in the Foster research laboratory investigate the sources, reactions and transport of contaminants in the aquatic environment. Currently, we have two ongoing lines of active research. The first involves determining the amounts and sources of polychlorinated biphenyls (PCBs) in storm runoff in the Anacostia River, a tributary of the Potomac River that runs through Washington, DC.

PCBs are persistent, carcinogenic organochlorine contaminants that are thought to adversely affect both human and environmental health. The Anacostia River is one of the three most heavily contaminated PCB regions in the Chesapeake Bay watershed, where the highest sedimentary PCB concentrations have been reported to date. We are aiding in a massive clean up of PCBs in the Anacostia River. Storm flow runoff is the primary mode of input of PCBs in the Anacostia River, and storm flow inputs must be characterized to design effective, long-term clean up strategies.

The second line of research is in determining the inputs of pharmaceutical and personal care chemicals in the Potomac River. Over 32 wastewater treatments plants in the metropolitan DC region release pharmaceutical chemicals through wastewater discharge, and some of these biologically active chemicals are severely impairing reproductive development in fish species by serving as estrogen mimics (as recently reported in the Washington Post). We are investigating the nature of pharmaceutical chemical inputs and potential estrogenic effects in aquatic organisms.”

Dr. Benoit Van Aken: “The mission of the Van Aken’s Environmental Molecular Biology Lab is to develop and apply molecular biology tools to solve environmental issues.

Dr. Van Aken’s primary research interests have focused on the development of molecular biology methods for various environmental applications, including bioremediation, biofuel production, and water quality surveillance. He is currently conducting research in two major areas: (1) the molecular response of organisms exposed to environmental stressors (toxicogenomics) and (2) the development of molecular biomarkers for the detection of harmful aquatic organisms, including pathogens, invasive species, and toxic algae. Dr. Van Aken has been PI or co-PI on multiple research projects funded by state and federal agencies, including NASA, NIH, NSF, PennDOT, SERDP, and USDA.”

Dr. Xiaoyan Tan: “Our group focuses on the discovery of functional and multifunctional inorganic solid-state materials, ranging from intermetallics to oxides, with applications in technology and energy conversion. We specifically target materials with noncentrosymmetric and polar space groups, which include (but not limited to) metallic oxides, oxide thermoelectric materials, multiferroics, and magnetic semiconductors.

Students will be trained on the synthesis of crystalline inorganic solid-state materials by various methods, growth of single crystals, structural analysis, calculations of the electronic structure, and characterization of the physical properties of inorganic solid-state materials. Students will also have the opportunity to learn X-ray neutron diffraction while using state-of-the-art research facilities at national laboratories such as Argonne National Laboratory (ANL), Brookhaven National Laboratory (BNL), National Institute of Standards and Technology (NIST), and Oak Ridge National laboratory (ORNL).”

Dr. Rebecca Jones:  I study the chemistry of photography and alternative processes, such as mordancage. Using analytical techniques, I am curious about the changes to silver in relation to different binders in photographic paper. 

Dr. Mikell Paige: The focus of our lab is drug discovery. We utilize medicinal chemistry strategies for the design and synthesis of small molecule modulators of dysfunctional enzymes. We utilize structural biology and computational chemistry in conjunction with kinetic assays to determine enzyme mechanisms. Our capabilities also include the design, synthesis, and characterization of peptidomimetic inhibitors of protein-protein interactions.

Targets we are currently pursuing in our lab are mainly focused on diseases of the lung to include chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). We are also developing projects targeting viral infections, gram-negative bacterial infections, and traumatic brain injury (TBI).

Current Projects

■ Design and synthesis of small molecule modulators of the leukotriene A4 hydrolase enzyme for pulmonary inflammation

■ Inhibiting protein-protein interactions with modified natural product macrocycles as a strategy for targeting idiopathic pulmonary fibrosis

■ Determining the kinetic mechanisms for small molecule activators of enzymes

■ Iterative approaches to the synthesis of new peptidomimetic scaffolds

Dr. Chao Luo: “Dr. Luo's current work focuses on (1) structure design and material fabrication for organic alkali-ion batteries, (2) high-energy lithium sulfur batteries, and (3) all-solid-state lithium batteries.

Dr. Luo’s research explores the use of organic/inorganic materials and new fabrication techniques to design and synthesize novel organic electrodes, porous carbon, nanostructures and their hybrid composites to address environment and energy challenges.  A fundamental understanding of reaction mechanism and kinetics, investigation of structure-property correlations and development of functional structures and devices will be explored.”

Dr. Andre Clayborne
The Clayborne Research Group aims to develop novel technologies and materials through scientific discovery.  We use computation to study the chemical and physical properties of nanoscale materials. The group is also developing innovative approaches to education in science, technology, engineering, and mathematics (STEM). Current research interests include the design and virtual screening of nanomaterials for catalysis, developing organometallic nanoparticles for biological applications, battery research, STEM education, and algorithm development. Research is often multidisciplinary, spanning across chemistry, physics, chemical engineering, education, and computer science.

Chemical and Physical Properties of Structurally Precise Nanoparticles

Structurally precise nanoparticles provide an intermediate state between molecular and bulk phases of matter.  Subsequently, the properties can be strikingly different from both molecular and bulk systems.  Adding to their intrigue is the ease at which their inorganic metallic core can be functionalized with organic or metal-organic ligands.  This along with their (sub)nanometer size, has promoted their exploration as components of nanoelectronics, biosensing schemes, photochemical applications, and as electrocatalysts. Understanding these systems can lead to advances in photochemical, electrochemical, and environmental technologies.

We use computational models to characterize the chemical and physical properties of a series of organometallic nanoparticles.  We probe photodynamic and electronic properties, nanoparticle formation and dissociation, and the properties of their assemblies.  Often we try to correlate our results to experimental observations through collaborative efforts.

Modeling Electrochemical and Heterogeneous catalysis

Catalysis is key in a variety of industrial, biological, environmental, and technological fields. Being able to predict and design materials that can outperform previous surfaces and devices is critical for improving catalytic technologies.  At the core of developing future materials, one must understand not only the reaction networks, but also the role of substrate morphology and electronic structure.  We are interested in understanding the mechanistic details of various reduction and oxidation reactions on various metal-oxide and nanoscale organometallic structures using computational approaches.  

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Dr. Hao Jing
The research objectives focus on the synthesis and characterization of optically-active gold and/or silver nanoparticles as well as hybrid nanostructures made of two or more compounds with a high degree of dispersed uniformity in size and shape. These questions are investigated via simple and robust wet chemistry methods based on the characteristics of the solution.

The second research focus is on lanthanide-doped or rare-earth doped upconversion nanoparticles (UCNPs) which is a unique type of luminescent nanosubstance with the capabilities to convert low-energy (long wavelength), near-infrared photons into high-energy (short wavelength), fluorescent emissions which are highly tunable across the ultraviolet (UV) and visible spectral regions.

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Current Projects

■ We are currently interested in metal-semiconductor core-shell hybrid hetero-nanostructures with extinction peaks tuned to near-infrared (NIR) spectral region. This will lead to the efficient conversion of solar energy especially the NIR portions into chemical energy through photocatalytic reactions by utilizing novel anisotropic hybrid nanostructures.

■ Another current project is the rational design of smart probes based on NIR-excited lanthanide- doped upconversion nanoparticles (UCNPs) for latent fingerprint imaging and particularly, encryption.

■ We are also interested in intelligent NIR light-triggered anticancer drug release utilizing novel nanostructures based on UCNPs and their derivatives due to their remarkable advantages such as deep penetration depth, no blinking or biotoxicity and non-invasiveness.

Select Publications

■ H. Jing et al., Tunable plasmonic nanoparticles with catalytically active high-index facets. Nano Letters 14, 3674-3682 (2014).

■ H. Jing et al., Structural evolution of Ag-Pd bimetallic nanoparticles through controlled galvanic replacement: effects of mild reducing agents. Chemistry of Materials 27, 2172-2180 (2015).

■ H. Jing et al., Epitaxial growth of Cu2O on Ag allows for fine control over particle geometries and optical properties of Ag-Cu2O core-shell nanoparticles. Journal of Physical Chemistry C 118, 19948-19963 (2014).

■ H. Jing et al., Controlled overgrowth of Pd on AG nanorods. Cryst Eng Comm. 16, 9469-9477 (2014).

The Center for Clean Water and Sustainable Technologies (CCWST) was chartered on April 2008. The center idea was prompted by winning the 2007 National Academy of Engineering- Grainger Challenge for Sustainability prize by Dr. Abul Hussam of the Department of Chemistry and Biochemistry. The primary focus of the center is to find chemical and biochemical ways to obtain clean water through a process of measurement, characterization, and mitigation method development.  The center is a key contributor for the development of the SONO Water Filtration System, which is now used by over a million people affected by arsenic in groundwater.

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Questions may be sent to the director, Dr. Abul Hussam, ahussam@gmu.edu

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