Robin L. McCarley, Ph.D. - US grants

This award is the starter grant increment of Dr. McCarley's Postdoctoral Fellowship in Chemistry. Scanning tunneling (STM) and atomic force (ATM) microscopy studies will be carried out on thin metal films formed upon organic monolayers containing pendant metal binding sites. Surface diffusion of adatoms should be controllable by varying the tail group thus allowing better control over metal film properties. ATM and STM will be used to monitor the morphology of metals formed on these modified surfaces. Metal films produced by vacuum evaporation will be investigated in order to note differences in nucleation events. %%% This research will study methods which can lead to the preparation of thin metal films. These materials are of considerable commercial importance to the electronics industry.

This Chemistry Division award provides continued support for a Research Experiences for Undergraduates (REU) site in the Chemistry Department, Louisiana State University (LSU). Drs. Robert P. Hammer and Robin L. McCarley will coordinate the 10-week summer program for the next three years. Ten students from institutions other than LSU will carry out research in all areas of chemistry. Activities will emphasize finding chemical information, written and oral communication, and presentation skills, as well as knowledge of research and career opportunities in the chemical sciences. A series of lectures and tours will be given by professional chemists drawn from industry, national laboratories and government agencies. During the last week of the program, participants will prepare a presentation for the joint poster session with students supported by other summer programs, including the Louisiana Alliance for Minority Participation and the Howard Hughes Biomedical Research Institute

In this work, supported in the Analytical and Surface Chemistry Program in the Chemistry Division, Robin L. McCarley of Louisiana State University, Baton Rouge, will study ways to modify self-assembled monolayers (SAMs) on an in place basis. A major thrust of the project is to use electrochemical polymerization to manipulate reactions in SAMs to produce surfaces with specific properties. The chemistry uses conducting thin film poly(pyrrole) polymers produced from substituted alkyl thiols attached to gold surfaces. A number of instrumental methods will be used to study the films that are produced. One, attenuated total internal reflection Fourier transform infrared spectroscopy, is particularly useful because it produces information about the chemical composition of the surface of the material. Scanning tunneling microscopy and scanning force microscopy are to be used to provide information about surface topography and structure. The objective is to correlate macroscopic properties of the thin film materials with molecular structure. This investigation will study ways to control the chemistry involved in the formation of organic thin films constructed on gold surfaces which serve as a physical support for the film. The purpose is to produce film materials with physical and chemical characteristics tailored to a specific application. In the long term, this will enable construction of sensors for environmental monitoring and other purposes which have high molecular specificity.

This award to Louisiana State University and Agricultural & Mechanical College (LSU) is from the Major Research Instrumentation program and the NSF/EPSCoR program. The award supports the acquisition of a combination Auger (AES) scanning Auger microscopy (SAM) and high resolution X-ray photoelectron spectroscopy (ESCA) surface analysis system. This state of the art system will enable high-resolution energy, depth and spatial characterization of a variety of novel thin-film/surface materials at levels that are currently unavailable at the institution. The instrument will be combined with exiting instrumentation and will constitute the nucleus of a centralized campus-wide Materials Characterization Facility. The facility will be accessible to scientists and students from Southern University, and will support several federally funded projects. It will enhance substantially the infrastructure in and impact the visibility and competitiveness of LSU and Southern University.

This award to Louisiana State University and Agricultural & Mechanical College (LSU)is from the Major Research Instrumentation program and the NSF/EPSCoR program. The award supports the acquisition of a combination Auger (AES) scanning Auger microscopy (SAM) and high resolution X-ray photoelectron spectroscopy (ESCA) surface analysis system. This state of the art system will enable high-resolution energy, depth and spatial characterization of a variety of novel thin-film/surface materials at levels that are currently unavailable at the institution. The instrument will be combined with exiting instrumentation and will constitute the nucleus of a centralized campus-wide Materials Characterization Facility. The facility will be accessible to scientists and students from Southern University, and will support several federally funded projects. It will enhance substantially the infrastructure in and impact the visibility and competitiveness of LSU and Southern University.

The researh project by Dr. Robin McCarley of Louisiana State University entitled "Stabilized Molecular Assemblies" is supported by the Analytical and Surface Chemistry Program. The goal of the research is to control the 2-dimensional polymerization of dendrimer assemblies and then to utilize the macromolecule as a container for specific guest molecules, which can be released through electron-transfer chemistry. The investigator will study the macromolecule formation as well as, the trapping and release properties of the oligomers. A key objective is the development of selective traps with reversible release properties. This research represents an extension of the investigator's prior work, while also branching out into new fields of exploration.

The ability to control the isolation, storage and release of small molecules has many potential applications with potential for societal impact. These polymerized dendrimers may have utility for the preconcentration of specific target molecules, as nanoscopic sensors, as new materials and for drug delivery. A thorough and fundamental study of the chemistry and performance of these materials is significant.

This award provides support for a joint project aimed at the development of aggressive new analytical strategies for protein sequence analysis based on mass spectrometry. The effort involves investigators at Louisiana State University, who are accomplished in the manufacture of micrometer-sized devices, and their collaborator at the University of Cincinnati, who is skilled in high resolution mass spectrometry. Microfabrication techniques will be used to develop integrated micro-systems expected to permit analysis of the proteins in a single cell. The use of microfludics will help maintain the proteins at a high enough concentration to permit analysis even though the amount of each protein found in a cell is on the order of 3000 molecules. The devices to be used in this project are built using polymers and micromanufacturing techniques to fabricate high-aspect-ratio molding dies for hot embossing polymers. The devices will be tested and refined through studies of chloroplast-derived membranes thought to contain at least 150 different proteins. Within the context of the proposed effort, these studies will be extended to examine the proteome, i.e., the entire complement of proteins, of intact chloroplasts of Arabadopsis and of entire cells of the blue-green algae Synechocystis. If fully successful, the instrumentation will allow biochemical analyses of individual cells and thus contribute to a better understanding of the relationship of gene expression and cellular phenotype.

NIRT: Combustion-Generated Nanoparticles--
The Role of Transition Metals in Nanoparticle and Pollutant Formation

CTS-0404314

This project addresses: 1.) The role of combustion-generated metal oxide nanoparticles in the formation/growth of primarily carbonaceous nanoparticles and 2.) The role of metal oxides condensed on growing nanoparticles in the formation of organic pollutants. Ni and Cu have been identified as important metals for initial study. The reactivity of their oxides under a range of conditions is being studied using a variety of experimental techniques. Dendrimeric synthesis techniques is used to create 1-3 nm metal oxide nanoparticles with and without associated carbonaceous layers; sol-gel techniques are used to create thin metal-oxide films on carbon and silica. The reactions of organic chemicals with these nanoparticle surrogates from 200 to 1100 C under oxidative and pyrolytic conditions are studied using a high-temperature flow reactor coupled with GC-MS, EPR, and FTIR analysis. Metal-catalyzed PAH formation is studied using HPLC-UV absorption. The nature of the metal oxides and their chemical binding is characterized using x-ray spectroscopic techniques at the LSU synchrotron facility. Ab initio modeling techniques are used to assess nanoparticle geometries, reaction sites, possible reaction mechanisms, and how they may vary as a function of particle size and metal identity.
It has been estimated that over 650,000 people die prematurely in the US each year due to exposure to airborne fine particles. PM2.5, defined as particles with a mean aerodynamic diameter of less than 2.5 microns, have been shown to initiate cardiopulmonary disease and cancer in exposed populations. It has been realized only recently, however, that submicron, combustion-generated nanoparticles are the likely cause (alone or in combination with other pollutants) for the majority of these deaths and associated illnesses. Although health-effects research programs have been initiated by NIH and EPA, the causative agents remain unknown and progress is hindered by lack of understanding of the complex composition and reactivity of combustion-generated nanoparticles. The impetus of this program is practical, viz. to understand the origin and nature of combustion-generated nanoparticles so that their environmental impact can be minimized. The goal is contribute to the understanding of the chemical factors impacting the health effects of combustion-generated nanoparticles so that their effects can be mitigated or eliminated through combustion control.

Technical Abstract. An asymmetric field flow fractionation device with on-line light scattering detectors, both static and dynamic, will permit high-resolution measurements of the size and molecular weight distributions of particles and assemblies. The system, which can handle aqueous or non-aqueous samples, will benefit these primary projects: formation of amyloid fibrils, which is a key process in Alzheimer's disease; responsive dendrimer superstructures designed to trap and release guests, such as drugs, toxins, and reagents, on command; early assembly of precursors to noncovalently stabilized polymer gels with potential as nanoscale scaffolds; evaluation of silica-polypeptide composite particles designed to produce responsive colloidal crystals; and, interactions in polymer-clay composites being developed for artificial skin applications. Secondary projects include characterization in support of virus preparation and function, physicochemical behavior of polyelectrolytes, and novel cone-shaped vesicles. The large size and often-delicate nature of the particles of interest makes them difficult or impossible to characterize by gel permeation chromatography. Other competing methods, such as cryo electron microscopy, are sometimes subject to preparation artifacts or undersampling errors. Most of the particles to be investigated carry an electrical charge; therefore, the request includes equipment to measure zeta potential, which is related to the effective charge on a molecule or particle in solution. This also permits routine biophysical measurements, such as the isoelectric point of proteins and subtle changes in their size under biologically relevant conditions. The new equipment will permit an older light scattering device to be retired and then reborn in the hands of student designers. The outcome will be an instrument that transcends commercially available designs for applications such as microrheology and rapid self-assembly.

Non-technical Abstract. The requested equipment can measure the size and mass of nanoparticles, polymers and their aggregates, both synthetic and naturally occurring. For example, Alzheimer's disease is thought to progress through the accretion of very small protein fragments into huge structures. The requested equipment will help assess the efficacy of drug candidates designed to intercept this process. The very same equipment will be used to characterize new synthetic materials that have the potential to carry drugs, remove environmental toxins, or isolate new materials in optically pure form. One component of the request is not widely available in publicly accessible laboratories. Its presence on the Louisiana State University campus leverages growing programs to improve both industrial outreach and diversity of our student body. The equipment adds significantly to the Louisiana Applied Polymer Technology Extension Consortium, a statewide university coalition whose primary mission is economic development in one of the poorest regions of the United States. The paucity of similar equipment in academic laboratories makes the equipment appealing to a wider audience of students, including summer interns supported by NSF-REU and a new, NIH-funded initiative targeting under-represented groups. The equipment supports a new research partnership with the University of Texas-Pan American, which trains a largely Latino student body. The equipment will play a key role in a new, interdepartmental, team-taught course, the first at Louisiana State University to address colloid science and its interface to nanoscale research and macromolecules.

DESCRIPTION (provided by applicant): The goal of this application is to evaluate the hypothesis that the contents of vesicles (liposomes) made of redox-responsive phospholipids can be efficiently released upon liposome interaction with a specific quinone reductase enzyme that is highly concentrated in the majority of cancer tumor tissues, namely, NAD(P)H:quinone oxidoreductase type 1 (NQO1, DT-diaphorase). Demonstration of this will allow for the future development of an unprecedented group of redox-sensitive liposomes that are structurally optimized to preferentially accumulate in tumors and deliver their contents in a site-specific manner, as the result of their being opened in response to the overexpressed reductase activities in cancer tumors. Highly specific destabilization of the quinone reductase-responsive liposomes is proposed to occur by selective, enzyme-catalyzed reduction of stabilizing quinone subunits of lipids composing the liposomes. Reduction of the quinone groups leads to cleavage of the covalent link between the quinone and the phospholipid in the liposome bilayer, yielding phosphatidylethanolamine lipids that are unable to sustain bilayers. Enzyme-specific reduction leads to destruction of the liposome and release of its contents. Specific Aims to evaluate the hypothesis include that of: 1) developing synthetically engineered quinone subunits having fast speeds of NQO1-catalyzed reduction and self-cleavage so as to yield a high rate for the overall NQO1-stimulated process;and 2) making quinone-lipid liposomes capable of rapid NQO1-activated destruction by optimizing the interaction of NQO1 with the quinone stabilizing subunits. These Aims will be achieved by completion of a set of carefully designed experimental Objectives that address the synthesis of quinone-lipids having thermodynamic reduction values and self-cleavage rates that are optimal for enzymatic destruction and the formulation of liposomes (composition of lipids) that leads to efficient NQO1 interaction with quinone subunits. This project directly addresses the development of a class of technologies with the potential to treat an important disease, cancer, as well as inflammatory tissue diseases, such as rheumatoid arthritis, that have associated with them overexpressed reductase enzymes. The methods and materials to be developed during this work are directly applicable to the missions of the Agency Institutes, including those of the National Institute of Biomedical Imaging and Bioengineering, the National Cancer Institute, and the National Eye Institute. PUBLIC HEALTH RELEVANCE: This research targets the development of a responsive nanoscopic system capable of containing drugs and then delivering them upon stimulation by the presence of a specific protein associated with cancer tumors. The responsive system has the potential to provide significantly more efficient chemotherapeutic treatment of cancer tumors with fewer side effects in comparison to the current, commercially available nanoscopic delivery systems. The long-term impact of the protein-responsive delivery system is great, for roughly 6 million deaths are attributed to cancer each year.

The Analytical and Surface Chemistry Program of the Division of Chemistry at NSF will support the research program of Prof. Robin McCarley of Louisiana State University. Prof. McCarley and his students plan to investigate how to prepare stimuli responsive liposomes with the capability to deliver molecules that are internalized in the liposomes as a result of liposome destabilization. They will investigate the mechanism and kinetics associated with liposome opening by chemical reducing agents and enzymes. The project could have significant impact on various industries that focus on environmental remediation, chemical analysis and drug delivery. The project will provide excellent training opportunities to graduate and undergraduate students in a highly multidisciplinary research area. It will also support the participation of Prof. McCarley and his students in the Louisiana Board of Regents "Speaking of Science" program for K-12 students and in the LSU's ChemDemo K-12 outreach program, which has already impacted 60,000 Louisiana students.

Interdisciplinary research is a major emphasis of modern biomedical and physical science efforts, and enabling interdisciplinary research is a major part of the NIH Roadmap. Biomedically-oriented, environmental interdisciplinary research is the theme of this Center/Program, and as such, requires a cross-cutting training program in support of the Superfund Center's educational activities. The role of the Training Core is to provide an Infrastructure and environment that promotes the development of post-doctoral and graduate students in the highly interdisciplinary field of surfaces of particulate matter. Importantly, the Training Core has Aims that focus on recruiting and multidisciplinary education of graduate and postdoctoral students. Proposal Objectives that will allow us to achieve the Aims include: offer a support staff that handles dally operations of the Training Core;foster interactions between faculty and participants;manage the Training Core via faculty leadership and involvement in the Core aims and objectives;establish an aggressive recruiting program for prospective post-doctoral fellows and graduate students through our on-going research programs, and faculty/student seminars at feeder schools, which include a group of Historically Black Colleges and Universities (HBCUs);recruit new graduate students from our existing PhD programs that are successful with recruiting and retention of scientists from all groups;increase postdoctoral and graduate student team-playing, self-motivation/reliance and breadth of research knowledge/skills by use of Superfund Teams;provide a set of core graduate courses for students;and augment the cross-interdisciplinary training through the use of a research rotation program. The Training Core of this Superfund Proposal will result in the training of students pursuing a doctor of philosophy degree or those furthering their post-graduate education in the highly interdisciplinary area of particle-associated air pollution and subsequent health effects of said pollution as studied by biomedical researchers. Students from diverse ethnic, gender, and scientific back grounds will be cross-trained so that they will become valuable contributors to the environmental workforce.

In this project, funded by the Chemical Measurement and Imaging Program of the Chemistry Division, Professor McCarley of Louisiana State University is developing optical methods for detecting specific proteins in biological cells in a highly efficient and selective manner. To meet this challenge, the McCarley group is designing and making, and implementing in human cell studies, a new series of smart dye molecules that are sensitive to the presence of specific protein analytes within the cells. The highly interdisciplinary approach provides an enriched learning environment for a team whose training and diversity make it possible to capably address measurement science challenges that span the physical and biological sciences.

The focus of this project is development and evaluation of new dye molecules whose fluorescent signal can be switched on, or the existing fluorescence can be changed to another energy, as a result of target analyte action on the dye molecules. The responsive dyes in this project are designed to selectively respond to the presence of particular enzymes, for example cancer-linked enzymes that are highly populated only within human cancer cells. High-integrity detection and differentiation of cancer cells from normal cells with the fluorescent dyes is being demonstrated by use of microscopy and cell counting methods. The broader impacts of this project include proven routes for the high-fidelity detection and imaging of cancer cells; the interdisciplinary training of scientists in a diverse, rich educational environment, that will enable them to address the ever-growing complexity of scientific challenges; dissemination of the work to scientific peers and the public through professional society meetings and public presentations; and the opportunity to influence female pK-12 students through high-impact outreach programs.