CEMITURE Projects

Dr. Karelle Aiken

Project Title: Anion and Heavy Metal SensorsDr. Shainaz Landge
Project Advisors: Dr. Shainaz Landge and Dr. Karelle Aiken

Project Description:  Heavy transition metals (HTM) are found in the environment and living systems. However, in excess, they may trigger health problems such as memory loss and cognitive issues, and environmental concerns. Determining the connection between HTM’s and disease development is quite challenging because the metals, which are retained in organs, only appear in trace amounts in blood or urine. Thus, it is essential to develop capabilities allowing for the detection of HTM’s in living systems and the environment at very low concentrations. Our research focus is to readily and effectively detect the HTM cations using novel 1,2,3-triazole molecular sensors. Various characterization techniques will help deduce the metal binding with the sensors. These triazole chemosensor can also be conjugated with biological (protein or DNA) or chemical (polymer) groups to enhance their applicability. Alternatively, the sensors can be fabricated on carbon nanotubes such that the metal detection can be characterized by ionic rectification method.

Anion and heavy metal sensors 1Role of the Research Student:  Probe various metals to determine the sensor’s binding site and metal-specificity using various instruments: UV-vis spectroscopy, fluorimetry, NMR, X-ray Crystallography and ionic rectification method.

 

 

 


 

Project Title: Design and Synthesis of Novel Organofluorine Compounds as Potential Therapeutics for Cancer

Advisor:  Dr. Abid ShaikhShaikh transition metal-based catalyst 1

Dr. Abid ShaikhProject Description:  Csp2-H functionalization using transition metal catalysts proved to be a valuable tool in C–C bond formation. In contrast, Csp3–H activation of alkyl groups directly attached to aromatic rings is less explored. Substituted azaarenes are ubiquitous in a wide range of compounds that are important in materials and have been found to be the most prevalent heterocycle in bioactive compounds. Our research goal is to utilize transition-metal-catalyzed chelation-assisted methods for C–C bond formation to expand the reaction scope for the synthesis of diverse sets of functionalized azaarenes. To complement transition-metal-catalyzed processes, we will probe Lewis acid-catalyzed coupling of benzylic Csp3-H in 2-alkyl-substituted azaarenes with electron deficient carbon atoms in pyruvates (1), imines (2), amines (3) and alcohols (4) (see Scheme).

Role of the Research Student:  Designing experimental procedures and executing synthesis reactions. Students will learn various techniques in synthesis such as, experimental setup, isolation, purification, and structure elucidation of organic compounds. They will also use instruments such as NMR, mass spectroscopy (MS), and IR-spectrometers in analyzing their synthesized compounds.

The research student will be encouraged to participate in related scientific conferences and apply for any possible grant opportunities.

 


Project Title:  Quantum Chemical Analysis of Nanomaterials for Biomedical and Aerospace Applications

Advisor:  Dr. Ryan Fortenberry

dr-ryan-fortenberry

Project Description: The 2016 Nobel Prize in chemistry was awarded for the synthesis of nanomachines. The largest part of their award was for the physical creation of these devices.  However, synthesis is a tricky means of exploring chemical creativity.  In quantum chemistry, any molecular system can be created with the click of a few buttons or input of a few keystrokes.  Furthermore, modern methods are allowing for larger molecules to be modeled in such a fashion. ryanfortenberry-propellers

Recent work in our group has shown that disulfide bonds can be used to make blades for nanopropellers. The intrinsic desire of chalcogens to twist out of planarity in their homoatomic bonds has been manipulated to create a natural blade surface in a barellene-like structure.  This work will extend our understanding for an entire class of nanopropellers.  The goal is to attach these propellers to buckyballs so that endohedral cargos can be delivered with more precision. The hardest part is in attaching the propeller to the cage. Other work in our group has shown that carbon-doped boron nitride fullerenes (buckyballs) can stabilize the cages and create functionalization sites.  This would alleviate the need for bulky linkers between polymers of buckyballs or for functional groups like nanopropellers to be attached more efficiently.  How these buckyballs can be linked to each other or to nanopropellers is the focus for this study.

Role of the research student: (i) Employ quantum chemical programs to determine the nature of the structures in question. (ii) Analyze the potential energy surface of the propellers linked to model fullerene surfaces to ascertain the energy barriers for rotation for biomedical applications.  (iii) Explore the capability of linked fullerenes for polymeric applications including advanced materials for spaceflight and energy storage. (iv) Learn both graphical user interface (GUI) and command-line skills for scientific computing and quantum chemical analysis.

 


 

Project Title: Development of Polymers for the Treatment of Traumatic Brain Injuries

Advisor:  Dr. Hans Schanz

Dr. Hans Schanz

Project Description:  Cell free hemoglobin-based oxygen carrier (HBOC) products were on phase III human trial for the treatment of traumatic brain injuries (TBI). TBI is a leading cause of morbidity and mortality especially when complicated by secondary insults such as hypotension. However, unmodified HBOC’s have been shown to possess significant toxicity and hence, none of the trial HBOC’s was approved by the FDA. Polyethylene Glycol (PEG) and 2,2,6,6- tetramethylpiperidine-1-oxidyl (TEMPO) groups have been demonstrated to attenuate the oxidizing nature of the HBOC’s and hence, reduce their toxicity.

This project focuses on the development of HBOC’s modified in a novel approach with copolymers containing the desired PEG and TEMPO functionalities, thus enhancing their compatibility and optimizing their effectiveness in the treatment of TBI. We have identified Ru-alkylidene mediated Ring Opening Metathesis Polymerization (ROMP) based on ruthenium alkylidene complexes as the most favorable polymerization method to synthesize these copolymers. Due to the controlled-living nature of the polymerization process, we will control the composition as well as the sequence (statistical or block). A third component of this material is the hemoglobin binding group. This will be introduced as a polymer end group via a chain terminating agent.

Role of the research student:  Produce two copolymers with monomers 2 and 3 which include a binding end group under inert gas (dry box, Schlenk techniques). Gel permeation chromatography, MALDI-ToF mass spectrometry and EPR spectroscopy will be used to analyze the properties of the polymers. If an HBCO is produced, a toxicology assay will be conducted via biological essays.

The participant will also present their findings at a local/regional conference and will co-author publications which include their contributions to this work.

Schanz functionalized copolymers for neuroprotection 1

 


 

Project Title: Microwave Superheating of Carbon Nanotubes

Advisor:  Dr. Rafael Quirino

Dr. Rafael QuirinoProject Description:  Our recent findings in the development of dry functionalization protocols for carbon nanotubes (CNTs) led to a Patent application on the utility of the superheating properties of CNTs when exposed to microwaves. We continue to explore possible use for the CNT superheating phenomenon under microwave irradiation. The current project investigates the superheating effect in three distinct systems. The first system consists of cell cultures designed to test the phenomenon as a novel method for the ablation of tumors. Another system studied is the dry mixture of transition metal salts and CNTs for the quick synthesis and reactivation of CNT-supported catalysts, in the absence of any solvents. The third system investigated is the fast cure of tung oil-based thermosetting polymers.

 

Quirino 1 Quirino 2

Quirino 1

 

 

 

 

 

 

Role of the research student:  Running microwave experiments on either aspect (cell ablation, catalysts or polymers) of the overall project. Initially, the student will screen different reaction conditions, such as microwave power time etc. Once the reaction is optimized the process is fine-tuned for the amount of CNTs added to the system and their dispersion throughout the material being heated. Besides standard laboratory techniques, participants involved in this project will learn how to operate a microwave reactor in order to promote the superheating of CNTs. They will be required to characterize all samples produced by a variety of techniques available at Georgia Southern, such as TGA, DSC, SEM, MALDI-TOF, DEA, etc. A critical analysis and interpretation of their results will lead them towards a better understanding of the system they will be investigating.

 


 

Project Title: Microwave based cancer cell ablation therapy using CNT in Zebrafish embryo tumor xenografts

Advisor:  Dr. Vinoth Sittaramane

Dr. Vinoth Sittaramane

Project Description:  Lack of specificity for cancer cells, resulting in serious side effects and treatment resistance remain the main impediments to successful cancer therapy. With the advent of nanotechnology, a variety of nanoparticles have been used for localized, site-specific treatment that prevents these inhibitions. Different types of nanoparticles have been used in various ways in the past few years to improve imaging, prognosis, drug delivery or killing of cancer cells. Based on their ability to heat up instantaneously, nanoparticles have been used in thermal ablation of cancer. Various functionalizations of nanoparticles provide cancer specificity, and laser treatment is generally used to induce heating.

We propose the use of microwaves to induce cell death by the instantaneous heating of carbon nanotubes (CNTs), with the advantage of more rapid and more intense heating. Microwaves alone have previously been used for tumor ablation of various tumors, including those of the lung and liver; precedence therefore exists for their use in organisms. Organismal effects will be determined in a pilot study using a zebrafish xenograft tumor model which has emerged as a major tool for drug screening, drug development, tumor angiogenesis and nanotherapeutic studies. Moreover, several studies have also shown that CNTs are biocompatible and produce no significant toxicity in zebrafish embryos. In view of several advantages of zebrafish embryos as a model and CNTs as nanotherapeutic agents, we will use a zebrafish xenograft tumor model to determine CNT based cancer cell ablation by microwave-irradiation.

 Role of the research student:  (1) Transplant GFP expressing human cancer cells into zebrafish embryos at 3-4 hours post fertilization (hpf), (2) screen and isolate embryos established cancer under a fluorescent microscope, (3) inject embryos with functionalized CNTs targeted against human cancer cells and (4)  microwave them using various parameters to activate CNTs and selectively ablate human cancer cells in the zebrafish embryo.

 


 

Project Title: Electrospun Silicon/Titanium Dioxide Nanofibers High Performance Lithium Ion Battery

Dr. Ji WuWu 1

 Advisor: Dr. Ji Wu

Project Description: Lithium ion batteries (LIBs) have been widely viewed as one of the most promising green technologies in the field of energy storage, including hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and storage systems for renewable and intermittent energy sources such as solar, wind, and nucleation power. However, several aspects including relatively high cost and poor performance limit the broader

Wu 2 applications of LIBs. Herein, a feasible and low-cost elelctrospinning technique combined with sol-gel chemistry is proposed to fabricate silicon nanocrystals confined in TiO2 nanofibers, for the purpose of making anode materials for high performance LIBs which possess high energy density, long cycle life, low cost and fast charging rates, whose synthetic strategy is shown in the following diagram.

 Role of the research student: (1) Use sonication to synthesize various ratios to make a sol-gel solution; (2) utilize electrospinning techniques to fabricate nanofibers using a homebuilt electrospinning setup; (3) vary reaction conditions to determine the relationship between the fiber diameters and mass ratio, and the electrochemical performance; (4)) determine the composition and morphology of these synthesized nanofibers using thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS); and (5) characterize the surface area of these nanomaterials using Brunauer–Emmett–Teller (BET) surface area analyzer.

 


 

Project Title: Examining the Acute Toxicity of TiO2 Nanofiber
Project Advisor: Worlanyo Eric Gato

 

Eric Gato 1Project Description: The Gato research laboratory at Georgia Southern University conducts biomedical experimental studies on susceptibility to metabolic syndrome (insulin resistance), including the developmental origin and the role of environmental chemical exposure in the induction of type-2 diabetes and pancreatic cancer, using epigenetic, genomic, and proteomic techniques and fate and chemodynamics of trace metals and nanomaterials. One major project in the Gato laboratory is to examine the potential toxicity and quantification of nanomaterials in complex biological matrix. The ultimate goal of this project is to analyze the bio-distribution of trace amount of carbon nanotubes quantitatively, sensitively and selectively using a facile isotope metal doping method, thus making the organ-distribution and toxicity studies of nanomaterials more reliable and accurate. In the interim, our laboratory is examining the acute toxicity of TiO2 nanofiber in Sprague Dawley rats. TiO2 has been used in cosmetics, waste water treatment and the protection of the skin against sun damage. However, there are concerns over adverse effects resulting from bio-effects. The objective of this study is to employ proteomic and genomic techniques to investigate the effects associated with the oral ingestion of TiO2 nanofiber by Sprague Dawley male rats.

 

Research Plan for REU Participant: The projects outlined above will provide undergraduate students the opportunity to perform research at the interface of chemistry and biology. Participants involved in these projects will examine the role of oxidative stress and inflammatory response in the toxicity of TiO2 nanofiber or in the induction of diabetes. Specifically, participants will design polymerase chain reaction (PCR)  primer targets specific to oxidative stress and inflammation, extract total RNA from the liver or lung or pancreatic tissues, synthesize cDNA,  run quantitative PCR reactions, employ RNA gel electrophoresis to examine RNA quality. Thus, the participant will be able to determine the overall gene expression. Finally the participant will validate gene expression patterns via ELISA and immunohistochemical techniques.


 

Project Title:  Food Safety/Toxicology
Project Advisor: Dr. Evans Afriyie-Gyawu

Dr. Evans Afriyie-Gyawu

Project Description:  Many slaughterhouses or “abattoirs” in some developing countries (such as Ghana and Nigeria) are known to frequently use open fires, set with scraps of automobile rubber tires, to singe the fur of slaughtered goats, sheep, cows, etc. intended for human consumption. A report obtained via the U.S. EPA indicates that chemicals emitted through open tire burning include carbon monoxide, sulfur oxides, nitrogen oxides, particulate matter (e.g., volatile organic compounds such as benzene), dioxins, polycyclic aromatic hydrocarbons (PAHs, e.g., benzo-a-pyrene [BaP]), polychlorinated biphenyls (PCBs), and heavy/toxic metals/metalloids (e.g., arsenic, mercury, cadmium, chromium, etc.). Toxicological implications of potential contaminants, associated with the tire burning, on the meat, slaughterhouse operators, consumers, individuals living in close proximity to the slaughterhouses, and the entire ecosystem have not yet been characterized. Therefore, the main objectives are to: 1) collect meat samples singed with scrap rubber tires, 2) determine the types and levels of chemical contaminants in the singed meat, and 3) characterize/ quantify the levels of potential chemical pollutants in the tire-based smoke.

 Role of the research student: Collect meat samples in Ghana, extract contaminants from the meat using chemical extraction processes using the accelerated solvent extraction technique, and analyze the extracted samples for levels of the 16 EPA PAHs (including BaP) based on the EPA method 8100, which employs GC-FID. Analyses of the toxic metals (e.g., As, Cd, Hg, Pb, Cr, etc) will utilize the ICP-MS methods. Also, the student researcher will be involved in the statistical analysis of the data generated.

 


Project Title: Assessment of Catalytic Behavior of Organic Catalyst-Gold Nanorod Composites Under Photo-irradiation
Project Advisor: Dr. John Stone

Project Description: Gold nanorods have been widely studied over the past 20 years due to their interesting shape-dependent optical properties, long-term stability, low cytotoxicity and myriad of applications including biomedical imaging, photothermal therapy, and catalysis to name a few.  Much of the catalytic work performed thus far has centered around processes that take advantage of the high surface area of these gold nanomaterials either alone or in combination with another metals such as platinum or palladium.  While these studies have resulted in numerous publications confirming catalytic activity of these materials, they remain somewhat ill-defined.  There has been very little work looking at the catalytic behavior of small organic molecules attached to the gold nanorod surface.  In this case, it is not the nanoparticle itself that will act as the catalysis but rather the electron movement along the surface of the nanoparticle when irradiated with light and/or local heating that would enhance the catalytic behavior of the attached organic molecule.  We propose beginning with the well-studied organic catalysis, TEMPO.  TEMPO is a radical based catalysis which is part of a larger group of related organic molecules called nitroxides.  They have been highly studied with respect to their ability to promote oxidation and polymerization reactions.  Currently, we are working on the conjugation of TEMPO to the surface of our gold nanorods via an amide coupling.  This is being accomplished by terminating the gold nanorods with –COOH groups and reacting them with a –NH2 derivatized TEMPO.  Once conjugation occurs it is important that the rods remain stable and maintain their integrity.  Once this step is complete, specific catalytic studies will follow.

 

Last updated: 3/30/2017

Department of Chemistry • PO Box 8064Statesboro, GA 30460 • cemiture@georgiasouthern.edu