Chemistry

Our research program is focused on the synthesis and characterization of novel polymeric and composite materials, with an emphasis on the control of nanoscale structure. Recent developments in polymer and colloid chemistry offer the synthetic chemist a wide range of tools to prepare well-defined, highly functional building blocks. We seek to synthesize complex materials from a "bottom up" approach via the organization of molecules, polymers and nanoparticles into ordered assemblies. Control of structure on the molecular, nano- and macroscopic regimes offers the possibility of designing specific properties into materials that are otherwise inaccessible. We are particularly interested in compatabilizing interfaces between organic and inorganic matter as a route to combine the advantageous properties of both components. This research is highly interdisciplinary bridging the areas of physics, engineering and materials science with creative synthetic chemistry.

Dr. Polt began his research career by developing methods for amino acid synthesis in Prof. Marty O’Donnell’s lab at IUPUI. After that he was trained in the art of Organic Synthesis in the laboratories of Profs. Gilbert J. Stork at Columbia University and Dieter Seebach at the ETH in Zürich. He has continued to develop novel synthetic methods for amino acids, amino alcohols, glycosides and glycopeptides. Application of these methods resulted in the production of a number of pharmacologically active glycopeptides (GPCR agonists), alkaloid-like inhibitors of glycolipid processing enzymes and glycosyltransferases, as well as glycolipids with biological activity such as glycosphingolipids and rhamnolipids. The biological focus of his work has been in attempting to understand the chemistry of carbohydrates (e.g. glycolipids, glycoproteins) at cell membranes, membrane trafficking, and using these insights to design glycopeptide drugs from endogenous peptide neurotransmitters (neuromodulators, hormones) with enhanced stability in vivo that are capable of penetrating the Blood-Brain Barrier and interacting with GPCRs as agonists or antagonists. Presently, Polt studies the design, synthesis and testing of agonists related to the hormones Oxytocin and PACAP (Pituitary Adenyl Cyclase Activating Peptide), as well as other glycopeptide drug candidates.

Clinical applications of the glycopeptide drugs include pain, opioid use disorder, migraine, Parkinsons, Alzheimers and other neurogenerative diseases. In addition to lecturing and laboratory teaching during 35 years at the University of Arizona, and the publication of more than 137 scientific papers, he has mentored a large number of undergraduate, graduate (21 Ph.D.s granted, 2 in progress) and post-doctoral students who have taken positions in academia, industry and the US government. His Ph.D.s have hailed from the US (10), Czech Republic*, China, Germany*, India, Iran*, Ireland, Jordan*, Kenya*, Korea, Mexico* and Sri Lanka. Six of these Ph.D. graduates (*) have gone on to become naturalized citizens or obtain permanent resident status. Recent undergraduates associated with his research group have gone to graduate schools at Harvard, MIT, Boston University, University of Wisconsin, and Columbia University.

Jeanne Pemberton, PhD, is a household name in chemistry departments across the country. Her research on surface vibrational spectroscopy has enabled fundamental advances in the field of analytical chemistry.In her 25 years at The University of Arizona, Pemberton has received more than 40 research grants. Among the many boards and committees she serves, she was the chair of the Math and Physical Sciences Advisory Committee at the National Science Foundation in 2004. In addition to receiving the College of Science Distinguished Teaching Award, she has also received the distinguished American Chemical Society Award for Excellence in Analytical Chemistry, which is among the highest honors in her field.Dr. Pemberton’s group research seeks to develop an understanding of chemistry in several technologically important areas including electrochemistry and electrochemically-related devices, chromatography, self-assembled monolayers, surfactant systems, and environmental and atmospheric systems. Methodologies employed for these efforts include surface vibrational spectroscopies, near-field optical methods, electrochemistry, x-ray photoelectron spectroscopy, Auger electron spectroscopy, LEED, work function measurements, ellipsometry, electron microscopy, and the scanning probe microscopies AFM and STM. Molecular nanoscale imaging exists prominently in the ability to elucidate structural and mechanistic details of surface and interfacial chemistry.Two images of transient intermediate states on NaCl in its reaction with the mineral acids, HNO3 and H2SO4, are shown below. These transient structures are formed en route to the final surface products of crystalline NaNO3 and NaHSO4, respectively.Specific interfacial systems of interest include electrochemical battery and electroluminescent and electrochromic devices, models of these devices fabricated and studied in ultrahigh vacuum, organized molecular assemblies at solid surfaces or air-water interfaces formed spontaneously or by self-assembly or Langmuir-Blodgett techniques, chromatography stationary phase systems, soil and mineral systems important in the fate and transport of environmentally important chemicals, and surfaces such as ice, mineral acids, and alkali halides important in atmospheric processes.

William Montfort, PhD, determines the atomic structures of proteins and seeks to understand how protein structure gives rise to protein function – both in vitro and in living cells. At their heart, the problems have a fundamental structure-function question, but also address questions of importance to human health. Approaches include X-ray crystallography, rapid kinetic measurements, spectroscopy, theory, protein expression, drug discovery, molecular genetics and related techniques.Dr. Montfort is particularly interested in nitric oxide signaling mechanisms. Nitric oxide (NO) is a small reactive molecule produced by all higher organisms for the regulation of an immensely varied physiology, including blood pressure regulation, memory formation, tissue development and programmed cell death. He is interested in two NO signaling mechanisms: binding of NO to heme and the nitrosylation (nitrosation) of cysteines. NO, produced by NO synthase, binds to soluble guanylate cyclase (sGC) at a ferrous heme center, either in the same cell or in nearby cells. Binding leads to conformational changes in heme and protein, and to induction of the protein’s catalytic function and the production cGMP. NO can also react with cysteine residues in proteins, giving rise to S-nitroso (SNO) groups that can alter protein function. He continues to study the mechanistic details surrounding cGMP and SNO production, and the signaling consequences of their formation.For reversible Fe-NO chemistry, Dr. Montfort is studying soluble guanylate cyclase and the nitrophorins, a family of NO transport proteins from blood-sucking insects. Our crystal structures of nitrophorin 4 extend to resolutions beyond 0.9 angstroms, allowing us to view hydrogens, multiple residue conformations and subtle changes in heme deformation. For reversible SNO chemistry, he is studying thioredoxin, glutathione S-nitroso reductase (GSNOR) and also sGC. For regulation in the cell, Dr. Montfort and his group have constructed a model cell system based on a human fibrosarcoma called HT-1080, where sGC, NO synthase, thioredoxin and GSNOR can be manipulated in a functional cellular environment. With these tools, they are exploring the molecular details of NO signaling and whole-cell physiology, and undertaking a program of drug discovery for NO-dependent diseases. Keywords: Structural Biology, Drug Discovery, Cancer, Cardiovascular Disease

Katrina Miranda, PhD, claims nitric oxide (NO), which is synthesized in the body via enzymatic oxidation of L-arginine, is critical to numerous physiological functions, but also can contribute to the severity of diseases such as cancer or pathophysiological conditions such as stroke. This diversity in the responses to NO biosynthesis is a reflection of the diverse chemistry of NO. For instance, NO can alter the function of enzymes by binding to metal centers. This type of interaction could result in outcomes as disparate as control of blood pressure or death of an invading bacterium. NO can also be readily converted to higher nitrogen oxides such as N2O3 or ONOOH, which have very different chemical and biological properties. The ultimate result will depend upon numerous factors, particularly the location and concentration of NO produced. Therefore, site-specific modulation of NO concentration offers intriguing therapeutic possibilities for an ever expanding list of diseases, including cancer, heart failure and stroke. As a whole, Dr. Miranda is interested in elucidating the fundamental molecular redox chemistry of NO and in developing compounds to deliver or scavenge NO and other nitrogen oxides. These projects are designed to answer questions of potential medical importance through a multi-disciplinary approach, including analytical, synthetic, inorganic and biochemical techniques.The project categories include five major disciplines. First, she will work on the development and utilization of analytical techniques for detection and measurement of NO and other nitrogen oxides as well as the resultant chemistry of these species. Second, she will synthesize potential donors or scavengers of NO and other nitrogen oxides. Third, it’s necessary to describe chemical characterization of these compounds (spectroscopic features, kinetics, mechanisms and profiles of nitrogen oxide release, etc.). Fourth, Dr. Miranda will try to describe the biological characterization of these compounds (assay of effects on biological compounds, mechanisms and pathways, in vitro determination of potential for therapeutic utility, etc.). Fifth, she will identify of potential targets, such as enzymes, for treatment of disease through exposure to nitrogen oxide donors. Keywords: cancer treatment, pain treatment

Dominic Mcgrath, PhD, set forth a program which involves the use of organic synthesis for the design, development, and application of new concepts in macromolecular, supramolecular, and materials chemistry. Research efforts span a number of areas in the chemical sciences and include studies of: 1) chiral dendritic macromolecules and the effect of chiral subunits on dendrimer conformation, 2) photochromic dendrimers and linear polymers which undergo structural changes in response to visible light, 3) liquid crystalline materials based on dendritic and photochromic mesogens, and 4) synthesis of new ligands based on saturated nitrogen heterocycles.A continuing interest remains in the effect of structural perturbations on the properties and functional of dendritic macromolecules. Part of this research addresses the design, synthesis, and study of dendrimeric materials containing chiral moieties in the interior for influencing the conformational order of these 3-dimensional macromolecules. An ultimate goal is to develop materials active for the selective clathration of small guest molecules. Potential applications include chemical separations, sensor technology, environmental remediation, and asymmetric catalysis.Dr. Mcgrath and his lab team recently developed several new classes of dendritic materials containing photochromic subunits. As nature uses light energy to alter function in photoresponsive systems such as photosynthesis, vision, phototropism, and phototaxis, they use light energy to drive gross topological or constitutional changes in fundamentally new dendritic architectures with precisely placed photoresponsive subunits. In short, they can drive dendrimer properties with light stimuli. Two entirely new classes of photoresponsive dendritic macromolecules have been developed and include: 1) photochromic dendrimers and 2) photolabile dendrimers. Dr. Mcgrath anticipates that switchable and degradable dendrimers of this type will have application in small molecule transport systems based on their ability to reversibly encapsulate guest molecules. He continues to develop these materials as potential transport hosts and photoresponsive supramolecular assemblies.

Ron Lynch received a B.S. from the University of Miami (1978) with a dual major in Chemistry (Physical) and Biology, and a Ph.D. degree from the University of Cincinnati (1984) in Physiology and Biophysics. Dr. Lynch began training in optical imaging and MR spectroscopy of cardiac metabolism while at the NIH/NHLBI under the direction of Dr. Robert Balaban from 1984-1987. In 1987, Dr. Lynch moved to a staff position in the Biomedical Imaging Group with appointment in the Physiology Department at the University of Massachusetts Medical Center where he was involved in the development of approaches for 3-dimensional imaging including deconvolution and confocal microscopy. Dr. Lynch joined the faculty of the University of Arizona in 1990 with dual appointment in the Departments of Physiology and Pharmacology, and is currently a full professor, and director of the Arizona Research Institute for Biomedical Imaging. In 2000, Dr. Lynch was a visiting scientist at the Laboratory of Functional and Molecular Imaging and the Magnetic Resonance Imaging Center with Dr. Alan Koretsky at the NIH/NINDS. Dr. Lynch is a member of the Biophysical Society, the American Physiological Society and American Diabetes Association, and regularly serves on grant review panels for the JDRF, NIH/NIDDK, and NSF. Research in the Lynch lab focuses on second messenger signaling in vascular smooth muscle cells and nutrient sensing cells (e.g., Pancreatic Beta-cells) with emphasis on alterations in signaling that occur during development of Diabetes. We are developing methods to modify and analyze beta cell mass in order to evaluate the initiation of the pre-diabetic state, and efficacy of its treatment. Analyses of subcellular protein distributions, second messenger signaling, and ligand binding is performed in our lab using state of the art microscopy and analysis approaches which is our second area of expertise. Over the past 3 decades, our lab has been involved in the development of unique microscopic imaging and spectroscopy approaches to study cell and tissue function, as well as screening assays for cell signaling and ligand binding. Keywords: Diabetes, Cancer, Optical Imaging, Targeted Contrast Agents, Metabolism, Biomedical Imaging, Drug Development

My research interests are in organic and polymer chemistries that include extensive development of new polymers, polymerization chemistries, polymer characterization, and their applications, such as bio-microfuel cells, membranes, protective coatings, photoresists, sensors, and high surface area adsorbents. Presently, my research includes the development of new polymeric sunscreens, polymeric foams, novel materials and chemistries for 3D printing, synthesis and characterization of porous materials, new polymeric antioxidants, fluorescent polymers and particles, and extensive work in sol-gel science. Keywords: New Sunscreens

R. Clark Lantz, PhD Exposure to environmental toxicants alters lung structure and function and leads to chronic lung disease, including cancer. Current investigations are examining the effects of exposure to environmentally relevant doses of arsenic and uranium. Arsenic is a naturally occurring metalloid found in water, soil and air. Exposure to inorganic arsenic occurs worldwide through environmental (contaminated drinking water, air, food and domestic fuel sources) and occupational exposures (smelting industries, pesticide production). In addition to its association with non-malignant diseases, arsenic is of major worldwide health concern because of its carcinogenic potential in humans. Epidemiologic studies have associated arsenic exposure with an increased risk of multiple human cancers including lung, skin, bladder, kidney, liver and stomach cancers. Our current research is focusing on two models to examine the effects of arsenic in the lung. One model relies on exposure to arsenic during lung development, both in utero and postnatally. We have shown that exposure of pregnant female mice and their offspring to 50 or 100 ppb as arsenic in drinking water resulted in altered pulmonary function in 28 day old animals. Airways were more responsive to bronchoconstriction. These changes were specific for exposure during development and were not reversible if arsenic was withdrawn. Associated with these functional changes, arsenic exposure resulted in a dose-dependent increase in airway smooth muscle and alterations in airway connective tissue expression. We are currently analyzing mediators that may be involved in this response to arsenic. In addition, we are beginning investigations into the effect of inhalation of arsenic on lung development. We are also currently using in vitro airway epithelial cell cultures to determine the effects of arsenic on wound repair and epithelial barrier function. In collaboration with Dr. Scott Boitano, we have been able to show that arsenic inhibits wound repair. This may be due in part to arsenic- induced alteration in calcium signaling. We have also been able to show that arsenic alters expression of epithelial junctional proteins and decreases epithelial barrier resistance. Research is also on going to identify protein alterations in lung lining fluid as biomarkers of exposure and effect. This study uses the technology of proteomics to evaluate and identify biomarkers of chronic environmental exposure to arsenic by evaluating large numbers of proteins simultaneously. We are comparing alterations in protein expression in exposed human populations in Arizona and Mexico, human cell lines, and in vivo rodent studies. Patterns of alterations in protein expression, both common and unique to these different test systems, will be identified. Finally, we are evaluating the chemical genotoxicity of uranium. In addition to its radioactive effects, uranium may also have adverse health effects because of its interactions with cellular macromolecules. We have found that uranium causes DNA damage through forming adducts which results in single strand breaks. In addition, uranium also inhibits double strand break DNA repair in airway epithelial cells. Keywords: pulmonary toxicology, arsenic, early life exposures

Raymond Kostuk, PhD, has a primary goal to investigate photonic techniques that enhance the capabilities of imaging, communication, sensing, and light collection and concentrator systems. His research includes fundamental and applied studies of photonic materials and devices, as well as system concepts that are based on photonics.