2021 COES Senior Projects Conference

Rapid Determination of Bromine in Louisiana Rice Husk with XRF

Team Member: Rachel Honeycutt

Advisor: Dr. Sven Eklund

The use of methyl bromide as a pesticide in Louisiana has been outlawed at the federal level, but still sees continued use. A rapid test was developed to determine bromide in Louisiana rice and rice husk samples using x-ray fluorescence (XRF). The samples were prepared in two different ways: raw rice and rice husk were ground to a powder, pelletized, and directly analyzed for bromide, and bromide was extracted from raw powdered rice and rice husk using soxhlet extraction with water and ethanol followed by centrifugation before XRF analysis as liquid samples. Numerous samples of rice and stalk were collected from Louisiana rice farms. The XRF data from both rice stalk processing methods produced a variety of bromide concentrations from 0 to 20 ppm, leading to the conclusion that methyl bromide is still being used as a pesticide during the growing process. Similar XRF data from the rice itself did not reveal any bromide at the ppm level, leading to the conclusion that even when methyl bromide is used, the level of bromide in the rice product is acceptably low. From this study, it can be deduced that bromine has not been entirely phased out of the rice-growing business as it should be, but is not a danger for consumption. Further study would include testing rice and rice husk samples from more farms to produce a larger data set and streamlining the powder/pellet test for bromide determination.

Chitosan-Genipin Hydrogels for Wound Healing

Team Member: Megan Ward

Advisor: Dr. Mary Caldorera-Moore

Hydrogel biomaterials composed of the carbohydrate polymer chitosan are beneficial for wound healing applications due to chitosan’s innate antimicrobial and hemostatic properties. Previously, Caldorera-Moore and colleagues have reported on the synthesis and characterization of chitosan-genipin hydrogels. To further optimize these hydrogels for clinical use, this capstone chemistry project has focused on evaluating the effects of chitosan-genipin hydrogel synthesis and post-processing techniques on free amine groups in the hydrogel network. These free amines provide chitosan with its antibacterial properties; however, as crosslinking occurs the number of free amines available decreases. Through a ninhydrin assay, the concentration of free amines was calculated as a function of batch-to-batch variability, rinsing time, and uniformity within the hydrogel network. Using a p-test and Tukey honestly significant difference test, the changes in concentration of free amines for the treatment groups were found to be statistically insignificant. To further understand the crosslinking mechanism, the chitosan-genipin hydrogel precursor solution was cured at 50°C within the spectrometer to obtain real-time 1H NMR spectra as crosslinking occurred. Calculating the remaining concentration of free amines and exploring the mechanism for the crosslinking reaction allows for the optimization of these wound healing devices.

Analysis of the Thermochemical Capabilities of Human and Animal Hair Waste as an Alternative Source of Bio-Renewable Energy by Use of Bomb Calorimetry

Team Member: Tyra Tatyanna Perkins

Advisor: Dr. Marsha Cole, Mrs. Jessica Wasserman

The extinction of fossil fuels has been a controversial topic for many years pushing the demand to search for an alternative bio-renewable source of energy. As the global population continues to grow exponentially, the demand for fossil fuels will also significantly increase as time goes on. As a result, scientists have explored different sources capable of producing harvest-able energy to keep up with projected energy demands in the midst of the rapidly declining fossil fuels. One bio-renewable source of potential energy that has yet to be researched thoroughly is hair waste from humans and animals. Therefore, the objective of this research project is to explore whether hair has the thermochemical potential to produce sustainable energy like that achieved by fossil fuels. To answer this question, the enthalpy of combustion of various human and hair types was determined using a bomb calorimeter calibrated against a benzoic acid standard. Preliminary results show that hair produces a minuscule amount of energy and would not be a viable replacement for thermochemical applications previously achieved using fossil fuels.

Determination of Heavy Metal Leaching from Children’s Face Paint

Team Member: Amia Galindo

Advisor: Dr. Sven Eklund

The cosmetic industry has been expanding and developing rapidly over the past few years. This progression spurs the need for adequate research, of which there has been extraordinarily little. This includes cosmetics designed for children, where there is even less research. In this document, the composition and toxicity of children’s Halloween face paint were tested using X-Ray Fluorescence along with multiple skin and stomach leaching tests. It was determined that some pigment contained Chromium, a toxic metal. A calibration curve was created, and the concentration in the face paint and left in the stomach and skin was calculated. While the concentrations discovered were low, research in the future should explore lasting effects and the other toxic components in cosmetics.

Determination of Heavy Metal Contaminants in Electronic Nicotine Delivery Systems via X-ray Fluorescence

Team Member: Margaret Boston

Advisor: Dr. Sven Eklund

The prevalence of adolescent vaping has become a public health crisis of epidemic proportions. Developments in electronic nicotine delivery systems (ENDSs) have created discrete units capable of delivering unprecedentedly high doses of nicotine alongside other harmful substances. One relatively under-researched harmful substance present in new vape products is heavy metals in END solutions and aerosols. This study aims to determine heavy metal contaminants in various ENDS. It was hypothesized that heavy metals would be present in concentrations in the parts per billion (ppb) range and that cheaper devices with fruit flavors that attract adolescents would display the highest concentrations of heavy metals. X-ray fluorescence (XRF) was used to experimentally determine heavy metal concentrations in the solutions and aerosols of three different brands of ENDS. XRF confirmed the presence of zinc, copper, and nickel in parts per million (ppm) concentrations in the solutions of two different fruit flavors of the cheaper disposable ENDs, partially confirming the experimental hypothesis. XRF showed zinc in one of the two remaining END brand solutions. Further research is needed to determine the health implications of these heavy metal contaminants.

Using Rice Husk and Sugarcane Bagasse in Hardened Cement Paste

Team Member: Sevario Robles

Advisor: Dr. Joan Lynam

One of the most used building materials in the world, if not the most used, is cement. However, with the high production of cement, specifically ordinary Portland cement, comes the high production of greenhouse gases. To counteract the emissions of these greenhouse gases, the addition or substitution of various products has been tested with cement. The use of byproducts mixed in with the cement can provide the necessary countermeasure that is needed for today’s climate. Rice husk and sugarcane bagasse are both waste products that are not being used in any other line of production which means they usually end up in landfills making them both abundant and inexpensive to obtain. When combusted, both the rice husk and the sugarcane bagasse become ash that has pozzolanic properties. What makes these waste products useful is the high silicon dioxide that is found within them can be used as partial replacements for OPC. The purpose of this study is to quantitatively evaluate the compressive strength, corrosion, and porosity resistance of hardened cement paste infused with rice husk ash and sugarcane bagasse ash so that it may partially replace OPC.

Synthesis and Cellular Uptake of an MK2 Inhibitor

Team Member: Alasdair Masson

Advisor: Dr. Scott Poh

Alcohol-induced liver disease (ALD) is the fourth leading cause of preventable death in the United States and is caused by the chronic consumption of alcohol. Progression of ALD can produce hepatic inflammation, causing liver failure through the development of fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Hepatic inflammation is stimulated by macrophage response to alcohol metabolism, where intracellular mitogen-activated protein kinase-activated protein kinase 2 (MK2), a downstream effector of the MAPK family member p38, continually upregulates the production of pro-inflammatory cytokines. Therapeutic inhibition of MK2 using cell-penetrating peptides (CPP) has been previously investigated as a possible novel treatment modality for chronic inflammation. To investigate whether a CPP MK2 inhibitor could be delivered to hepatocytes to treat inflammation, an anti-inflammatory CPP (KAFAK) was synthesized, and its cellular uptake was evaluated within activated HepG2 human hepatoma cells. Using fluorescence imaging, the cellular uptake of KAFAK into the hepatocytes was found to be successful, demonstrating a delivery mechanism for potential therapeutic applications involving liver inflammation.

Mechanochemical Synthesis of Cerium Beta-diketonate Complexes

Team Member: Bruce Labedis

Advisor: Dr. Elisabeth Fatila

Lanthanides are unique elements in the periodic table due to their propensity for the +3 oxidation state and their bonding which is predominately electrostatic in nature. The lack of covalent bonding in trivalent lanthanide cations is due to the shielding of the 4f valence orbitals by the filled 5s2 and 5p6 orbitals. Cerium is unique amongst the lanthanides because it has an accessible +4 oxidation state. Therefore, the electronic nature of the ligand used for coordination chemistry can be used to tune the oxidation state of cerium. The +3 oxidation state of cerium can be selectively stabilized by the use of electron-withdrawing ligands, such as hexafluoroacetylacetone (Hfac), a widely used and commercially available beta-diketonate ligand. A common cerium beta-diketonate starting material, Ce(hfac)3(H2O)3, was accessed mechanochemically by reaction of cerium trichloride hydrate and Na(hfac). Ce(hfac)3(H2O)3 crystals suitable for single-crystal X-ray diffraction (XRD) were obtained. These crystals were then characterized using infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), and elemental analysis. The results of the characterization showed that crystals still had impurities in the form of dinuclear complex. Further reaction of these crystals with 2,2’-bipyridine (BPY) was also carried out to determine the suitability of these materials for displacement reactions.

BREAK

Regulation of Inflammatory Cytokine Expression by MK2 Inhibitor Peptide

Team Member: Bryan Freeman

Advisor: Dr. Scott Poh

Mitogen-activated protein kinase activated protein kinase 2 (MAPKAP2 or MK2) is a kinase that is part of a cascade pathway responsible for releasing proinflammatory cytokines that play a major role in chronic inflammatory diseases. MK2 inhibitor peptides have been developed to regulate this pathway and reduce the expression of cytokines responsible for this proinflammatory response. In our lab, we synthesized our inhibitor peptide based on the MK2 inhibitor sequence found in prior research. Our goal was to identify the selectivity and effectiveness of our peptide in inhibiting MK2 expression and proinflammatory cytokine expression.

Utilization of Ammonium Chloride as an Alanine Racemase Inhibitor

Team Member: Dylan Groh

Advisor: Dr. Rebecca Giorno

Anthrax can be a deadly disease, which means that finding the optimal method of killing the Bacillus anthracis spores that cause anthrax is important to prevent infections. Difficulties arise due to the proclivity of the bacteria to form an endospore, which is a defense mechanism that protects the bacteria during unfavorable conditions. When conditions are favorable for growth of the bacteria, the endospore loses its resistant properties, entering the germination state. Therefore, it is advantageous to force the spore to enter the germinating phase, so the bacteria can be killed more easily. L-alanine has been found to be a germinant at high enough concentrations. However, the endospore contains Alanine Racemase (ALR), which inverts L-alanine into D-alanine, a non-germinant. If ALR was inhibited, then low concentrations of L-alanine would cause germination, allowing for the bacteria to more easily be killed. Several assays were performed using various concentrations of ammonium chloride, and fluorescence of the conversion of L-alanine to pyruvate was measured using a spectrophotometer. It was discovered that higher concentrations of ammonium chloride hinder other enzymes necessary to carry out the reaction, and lower concentrations of ammonium chloride do not produce a significant result regarding the concentration of L-alanine.

Determination of BHT (Butylated Hydroxyanisole)Vapors from Cereal Packaging Using Gas Chromatography (GC) and Flame Ionized Detector (FID)

Team Member: Prabal Jaki Banjar

Advisor: Dr. Sven Eklund

Food safety – which covers the entire food production process, from the beginning of food processing to the end of food packaging – has always been of great concern. The antioxidant BHT (Butylated hydroxyanisole) is present in our food as well as on the package to increase the shelf life of the food. The use of inks on packaging and the waxy plastic inside the cereal box may contain BHT which can migrate into the food during storage or shipment in varying temperatures and might affect taste and flavor and, more importantly, cause toxicity in the food. The gas chromatography (GC) technique with flame ionized detector (FID) will help determine the amount of butylated hydroxytoluene (BHT) mitigating from the plastic package at varying temperatures. Before the plastic package is run for the chromatography, it is heated at a certain temperature. The gas/vapor is collected during the condensation process, and ready to run for chromatography, results in chromatogram that can be used for quantitative analysis and compared between different samples collected at different temperatures. This method is accurate, sensitive, and highly reproducible, making it ideal for analyzing residual antioxidants in polymer food packaging.

Separation of Components Using Rotary Paper Centrifugal Chromatography Technology

Team Member: Alicia Kalinowsky

Advisor: Dr. Sven Eklund

In order to separate materials produced today for areas such as medicine, forensics, and the chemical industry in general, a new analytical and preparative method of rotary centrifugal paper chromatography has been developed, which can separate larger quantities than the average thin layer chromatography. The research involved the fabrication of 25 cm dia. methacrylate discs that sandwich several layers of chromatography paper. The rate of separation is increased by rotating the chromatography paper as a mobile phase is introduced through slots in the discs. This provides centrifugal force to the mobile phase and greatly increases the rate of separation. The compounds are separated as concentric rings instead of typical spots. The separated compounds in mobile phase solvent are then collected in vials as they exit the edge of the paper. In addition, we added the capability of UV-Vis detection of the separating bands by using a mini spectrometer with fiber optic transmission of the signal, which creates peaks similar to those in high-performance liquid chromatography. The materials and methods used along with results and conclusions gathered will be presented. Further research will include the application of the new technique to areas such as separating and analyzing plant extracts and forensic samples.

The Application of Xerogel in Paint and Cement

Team Member: Sarah Norwood

Advisor: Dr. Sven Eklund

Fly ash is a byproduct of burning coal in power plants and is either used in concrete or cement (class C) or placed in landfills (class F). Many researchers and companies are trying to find uses for class F fly ash. One application we are researching is the synthesis of a xerogel made from Class F fly ash. Xerogels are highly porous materials that can be added to various products to make them more lightweight and less thermally conductive. The fly ash was treated with sodium hydroxide at 350°C for one hour, followed by neutralization with hydrochloric acid, then combined with ammonia and air dried or oven-dried to produce a xerogel. In this research, we produced xerogel adjusted to three different pH values, and characterized the material with x-ray fluorescence (XRF), x-ray diffraction (XRD), infrared (FTIR), and scanning electron microscopy (SEM). The results of the xerogels added to paint and to geopolymer cement to lower their thermal conductivity will be presented. Hopefully, this type of research can lower the cost of xerogel, get fly ash out of landfills, and create new applications for engineers and chemists in the near future.

Synthesis and Application of Lipoprotein Receptor Protein-1 Ligand for Blood Brain Barrier Permeability

Team Member: Savanna Gonzalez

Advisor: Dr. Scott Poh

One of the main obstacles that there is for drug delivery, specifically macromolecules, to go into the central nervous system (CNS) is the blood-brain barrier (BBB). With the use of the receptor-mediated transcytosis (RMT) pathway then some macromolecules can permeate the BBB and go into the CNS. One promising receptor is the RMT. The RMT is the low-density lipoprotein receptor-related protein 1 (LRP1). It has been reported that a ligand peptide of LRP1, Angiopep-2, was permeable to BBB and was able to deliver covalently conjugated drugs to the CNS. The downfall of the LRP1 ligand is that there is no substantial LRP1 ligands to successfully conjugate with drugs of the LRP1 ligand for delivery into CNS. Because of this, our goal was to identify novel LRP1 ligands in order to investigate the LRP1-mediated RMT, and we were able to get a novel peptide that is the following: L57 (TWPKHFDKHTFYSILKLGKH-OH). A high BBB permeability of L57 was shown by way of in situ brain perfusion assay in the mice. This showed the first artificial LRP1-binding peptide with BBB permeability is what we discovered to be L57. This will help in the development of RMT-based drugs for treating many CNS diseases.