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CHEM2021AGUIAR5885 CHEM

Optimizing the Synthesis of Macrocycles

Type: Undergraduate
Author(s): Isabella Aguiar Biology
Advisor(s): Eric Simanek Chemistry & Biochemistry
Location: Zoom Room 3, 01:42 PM

In recent years, macrocycles have emerged to be potential drug leads, as they show to have promise for targeting disease pathways, however their synthesis is quite difficult and has yet to be optimized. Utilizing glycine specifically in macrocycle synthesis was the objective, and this was done by stepwise reactions of successfully adding compounds onto glycine to prepare for cyclization. Cyanuric chloride, BOC-hydrazine, and morpholine were successfully added to glycine, as proven with thin layer chromatography and NMR. However, problems that arose came with purifying the compound for cyclization due to solubility issues. Many attempts utilized column chromatography, but there seems to be promise in utilizing an extraction to purify the compound and prepare for cyclization.

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CHEM2021CRUZBARRIOS15423 CHEM

Determination of Critical Micelle Concentration from Diffusion-Driven Dilution of Micellar Aqueous Mixtures

Type: Graduate
Author(s): Eliandreina Cruz Barrios Chemistry & Biochemistry Onofrio Annunziata Chemistry & Biochemistry
Advisor(s): Onofrio Annunziata Chemistry & Biochemistry
Location: Zoom Room 3, 12:54 PM

Micellization is a phenomenon of central importance in surfactant solutions. Here, we demonstrate that the diffusion-based spreading of the free boundary between a micellar aqueous solution and pure water yields a one-dimensional spatial profile of surfactant concentration that can be used to identify the critical micelle concentration, here denoted as C*. This can be achieved because dilution of micelles into water leads to their dissociation at a well-defined position along the concentration profile and an abrupt increase in diffusion coefficient. Rayleigh interferometry was successfully employed to determine C* values for three well-known surfactants in water at 25 ºC: Triton X-100 (TX-100), Sodium Dodecyl Sulfate (SDS), and Polyoxyethylene(4)Lauryl Ether (Brij-30). The dependence of C* on salt concentration was also characterized for TX-100 in the presence of Na2SO4, NaCl, and NaSCN. Accurate values of C* can be directly identified by visual inspection of the corresponding concentration-gradient profiles. To apply the method of least squares to experimental concentration profiles, a mathematical expression was derived from Fick’s law and the pseudo-phase separation model of micellization with the inclusion of appropriate modifications. While Rayleigh interferometry was employed in our experiments, this approach can be extended to any experimental technique that yields one-dimensional profiles of surfactant concentration. Moreover, diffusion-driven surfactant disaggregation is precise, non-invasive, requires single-sample preparation, and applies to both non-ionic and ionic surfactants. Thus, this work provides the foundation of diffusion-driven dilution methods, thereby representing a valuable addition to existing techniques for the determination of C*.

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CHEM2021EDWARDS17380 CHEM

SQUARAINE DYES AS ENVIRONMENT-SENSITIVE PROBES WITH MULTIPLEXING ABILITIES

Type: Undergraduate
Author(s): Lauren Edwards Chemistry & Biochemistry Luca Ceresa Physics & Astronomy Jose Chavez Physics & Astronomy Sergei Dzyuba Chemistry & Biochemistry Zygmunt Gryczynski Physics & Astronomy Daniel Ta Chemistry & Biochemistry
Advisor(s): Sergei Dzyuba Chemistry & Biochemistry
Location: Zoom Room 5, 03:19 PM

Organic dyes with photophysical properties affected by alterations in the properties of the media, including viscosity, temperature, and polarity, are known as environment-sensitive probes. These probes are widely used in various areas of analytical, biological and material sciences. This poster will describe our initial efforts on designing multi-responsive environment-sensitive probes based on squaric acid scaffolds. Specifically, the incorporation of aminoquinoline moieties produced small molecule viscometers, which have the ability to sense polarity variations of organic solvents. Multiplexing abilities, coupled with modular and facile synthesis, distinguishes these probes from other types.

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CHEM2021FREIRE63707 CHEM

Hydrogen Peroxide Disproportionation with Manganese Macrocyclic Complexes of Cyclen and Pyclen

Type: Graduate
Author(s): David Freire Chemistry & Biochemistry Debora Beeri Chemistry & Biochemistry Kristof Pota Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry Benjamin Sherman Chemistry & Biochemistry
Location: Zoom Room 6, 01:34 PM

Oxidative stress is a result of an imbalance between reactive oxygen species (ROS) and the availability/activity of antioxidants. The catalase family of enzymes mitigate the risk from ROS by facilitating the disproportionation of hydrogen peroxide into molecular oxygen and water. Manganese containing catalase (MnCAT) consists of a binuclear manganese core bridged by carboxylate and single-atom ligands, likely water or hydroxide. In this work, hydrogen peroxide disproportionation using complexes of manganese with cyclen and pyclen were investigated due to the spectroscopic similarities of the latter with the native MnCAT enzyme. Potentiometric titrations were used to construct speciation curves to identify what complex compositions were present at different pH values. Based on these results, the complexes were made in situ by mixing stock solutions of ligand, buffer, and metal. The hydrogen peroxide disproportionation reaction was carried out in a sealed cell and PO2 measured using a microsensor (Unisense). When hydrogen peroxide was injected into the cell, disproportionation activity of the complexes was evident by (1) appearance of bubbles in solution, and (2) noticeable increase in PO2 as measured by the sensor. Spectroscopic investigation before, during, and after the reaction was used to follow changes in the UV-visible absorption of the complexes to collect information about the structure of the initial catalyst and any possible intermediate. Both, pyclen and cyclen were determined to form a dimeric structure under the reaction conditions used.

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CHEM2021GLOOR37466 CHEM

Synthesis of Isoleucine Based Macrocycles

Type: Undergraduate
Author(s): Camryn Gloor Chemistry & Biochemistry
Advisor(s): Eric Simanek Chemistry & Biochemistry
Location: Zoom Room 3, 02:23 PM

Many drugs today are small molecules and function through a specific binding with their target. This has proved to be efficient, yet the idea of larger macromolecules being used as drugs has grown more popular because of their flexibility. The issue with these larger molecules is that they have been previously difficult to synthesize. The emphasis of the research is to find an efficient way to synthesize macrocycles, reducing purification processes and side products. All reactions are done in solution and column chromatography is used to purify. An important aspect is testing if this cyclization method is possible with all amino acids or if limitations are present based on the backbone of the molecule. Because macrocycles have proved difficult to synthesize in the past, they are overlooked in the field of drug design. However, with this rather basic process it is possible to create new rules associated with drug design and defy what was once believed about macrocycles.

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CHEM2021GUEDEZ50076 CHEM

Genetic selection of sarcosine-specific synthetic riboswitches from a glycine riboswitch

Type: Graduate
Author(s): Andrea Guedez Chemistry & Biochemistry
Advisor(s): Youngha Ryu Chemistry & Biochemistry
Location: Zoom Room 6, 12:38 PM

The aptamer domain of a naturally occurring glycine riboswitches was randomized to generate a library containing billions of different variants. The dual genetic selection of this library was performed for sarcosine, a prostate cancer marker, and successfully led to the identification of sarcosine-specific synthetic riboswitches. When a chloramphenicol-resistance gene was expressed under control of these riboswitches, E. coli cells showed chloramphenicol resistance only in the presence of sarcosine. For a colorimetric assay, the sarcosine riboswitch gene was inserted upstream of the lacZ gene. When tested with various concentrations of sarcosine, the enzymatic activity of LacZ was proportional to the amount of sarcosine, clearly indicating the sarcosine-dependent gene regulation by the sarcosine riboswitch.

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CHEM2021HENDERSON7043 CHEM

DFT Simulations of the pKa Values of Triazines

Type: Graduate
Author(s): Nicholas Henderson Chemistry & Biochemistry
Advisor(s): Benjamin Janesko Chemistry & Biochemistry Eric Simanek Chemistry & Biochemistry
Location: Zoom Room 1, 12:46 PM

Triazines appear in pharmaceuticals, agrochemicals, and as building blocks for polymers used in materials science and medicine. Predicting the structure and dynamics in water as a function of pH requires reliable simulations of the pKa values for different sites for protonation. We present the initial DFT methods and continuum solvent for pKa of amines, ring nitrogens, and 2,4,6-triamino-1,3,5-triazine (melamine) derivatives. These M06-2X/6-311++G(2d,2p) calculations in SMD continuum solvent provide consistent accuracy for tested systems, use for future studies of more complex structures.

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CHEM2021JELINEK6743 CHEM

Synthesis of Organic Macrocycles for Anti-Microbial Testing

Type: Undergraduate
Author(s): Trevon Jelinek Chemistry & Biochemistry
Advisor(s): Eric Simanek Chemistry & Biochemistry Shauna McGillivray Biology
Location: Zoom Room 3, 02:55 PM

Organic synthesis and research into the activity and uses for macrocycle compounds have increased in recent years. These compounds proved to be an interesting field of research due to their size and ability to orient in different ways depending on the environment. The synthesis of these molecules is done by using a stable foundation molecule, cyanuric chloride, which is subject to substitution. The compound can be built from there using nucleophilic substitution with various nitrogen-based compounds. Then, in the final steps of the synthesis, the compounds dimerize forming the macrocycle. The amino acid nucleophile used to build the molecule is being varied to build many different compounds. The challenge, however, is to find the most efficient route for synthesis. I have successfully managed to synthesize one macrocycle compound using lysine with a Z protecting group as the starting material. Throughout the synthesis there was great difficulty with the compound’s solubility, therefore the starting material was switched to a BOC protected lysine amino acid. This resulted in better solubility throughout the process and yielded another successful macrocycle. These results demonstrate how the synthesis pathway we used to build these macrocyclic dimers is successful, but the process can be variable, based on the properties of the amino acid. It is recognized how the synthesis of these compounds is only the first step and further research into the properties and actions of the compounds is necessary. However, a pure product and efficient synthesis in making the macrocycle is important to properly access its properties. My further research will specifically test the antibiotic properties, if any, the macrocycles possess.

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CHEM2021NGUYEN20674 CHEM

Evaluating the therapeutic efficacy of a small indole-containing tetra-aza macrocyclic pyridinophane for treatment of Alzheimer's Disease

Type: Undergraduate
Author(s): Nam Nguyen Chemistry & Biochemistry Kristof Pota Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry
Location: Zoom Room 5, 01:10 PM

The mis-regulation of reactive oxygen species (ROS) and transition metals contribute to the onset of Alzheimer’s Disease (AD). A tetra-aza macrocyclic pyridinophane with an indole moiety, (Ind)PyN3, was evaluated on its radical scavenging reactivity and ability to chelate and stabilize the copper (II) oxidation state; these evaluations contribute to the overall therapeutic efficacy of the ligand in treating AD. Compared to a congener replacing the indole moiety with a hydroxyl moiety, (OH)PyN3, (Ind)PyN3 displayed comparable radical scavenging reactivity to (OH)PyN3. The fluorometric CCA assay revealed that (Ind)PyN3 was able to the stabilize the copper (II) oxidation state and prevent it from generating ROS via redox cycling at both 1 and ½ equivalents, albeit (OH)PyN3 was more effective at copper (II) oxidation state stabilization than (Ind)PyN3 at half molar equivalence. Our results demonstrate that the addition of the indole moiety to a tetra-aza macrocyclic pyridinophane does not disrupt radical scavenging reactivity by the indole moiety nor the ability of the pyridinophane to stabilize transition metal ions, warranting future exploration of the indole moiety in therapeutic design for AD.

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CHEM2021POTA8861 CHEM

Manganese Complex of a Rigidified 15-Membered Macrocycle: A Comprehensive Study

Type: Graduate
Author(s): Kristof Pota Chemistry & Biochemistry David Freire Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry
Location: Zoom Room 6, 02:15 PM

Owing to the increasing importance of manganese(II) complexes in the field of magnetic resonance imaging (MRI), large efforts have been devoted to find an appropriate ligand for Mn(II) ion encapsulation by providing balance between the seemingly contradictory requirements (i.e., thermodynamic stability and kinetic inertness vs low ligand denticity enabling water molecule(s) to be coordinated in its metal center). Among these ligands, a large number of pyridine or pyridol based open-chain and macrocyclic chelators have been investigated so far. As a next step in the development of these chelators, 15-pyN3O2Ph and its transition metal complexes were synthesized and characterized using established methods. The 15-pyN3O2Ph ligand incorporates both pyridine and ortho-phenylene units to decrease ligand flexibility. The thermodynamic properties, protonation and stability constants, were determined using pH-potentiometry; the solid-state structures of two protonation states of the free ligand and its manganese complex were obtained by single crystal X-ray diffractometry. The results show a seven-coordinate metal center with two water molecules in the first coordination sphere. The longitudinal relaxivity of [Mn(15-pyN3O2Ph)]2+ was found to be 5.16 mM−1 s−1 at 0.49 T (298 K). Furthermore, the r2p value of 11.72 mM−1 s−1 (0.49 T), which is doubled at 1.41 T field, suggests that design of this Mn(II) complex does achieve some characteristics required for contrast imaging. In addition, 17O NMR measurements were performed in order to access the microscopic parameters governing this key feature (e.g., water exchange rate). Finally, manganese complexes of ligands with analogous polyaza macrocyclic scaffold have been investigated as low molecular weight Mn(CAT) mimics. Here, we report the H2O2 disproportionation study of [Mn(15-pyN3O2Ph)]2+ to demonstrate the versatility of this platform as well.

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CHEM2021RAMOS32323 CHEM

Using parameters from a density functional theory model to add dispersion corrections to model noncovalent interactions

Type: Undergraduate
Author(s): Chloe Ramos Chemistry & Biochemistry
Advisor(s): Benjamin Janesko Chemistry & Biochemistry
Location: Zoom Room 1, 01:50 PM

Dispersion interactions also known as van der Waals interactions are essential for everything from nanomaterials to organic chemistry to biological chemistry. Modeling that chemistry requires modeling van der Waals interactions. Approximations that start from “freshman chemistry” molecular orbital (MO) theory do not account for dispersion. For example, helium-helium interactions are unbound in molecular orbital theory as two electrons are placed in antibonding orbital, but in reality, the interactions are weakly bound and can form a liquid. We have developed a density functional theory method embodying MO theory and corrections. Dispersion corrections can be added to noncovalent interactions in order to model them by using a standard model with different parameters. By fitting these parameters, the accurate known bond energies of real noncovalent complexes can be reproduced.

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CHEM2021RICHTER62964 CHEM

Fluorescent Bivalent Antibody Mimics Against Epidermal Growth Factor Receptor

Type: Undergraduate
Author(s): Mitchel Richter Chemistry & Biochemistry Andrea Guedez Pena Chemistry & Biochemistry
Advisor(s): Youngha Ryu Chemistry & Biochemistry
Location: Zoom Room 4, 03:11 PM

This project is aimed to develop triazine-based fluorescent bivalent antibody mimics against the epidermal growth factor receptor (EGFR), a protein disease marker for cancer. A synthetic gene for the anti-EGFR Z-domain was constructed by overlapping extension PCR and inserted into the pET-Z plasmid to produce pET-Z anti-EGFR. The anti-EGFR Z-domain variant was expressed as a C-terminal His-tag fusion in BL21(DE3) E. coli cells transformed with the pET-Z anti-EGFR plasmid and purified by immobilized metal ion affinity chromatography. A dansyl fluorophore was attached to the first position of a triazine core that has three positions available for modification. To the second available position of the dansyl-triazine conjugate, an anti-EGFR Z-domain molecule was selectively attached to generate a monomeric conjugate. Another anti-EGFR Z-domain molecule will be attached to the remaining position of the triazine core to produce a dimeric conjugate. We will test the fluorescent monomeric and dimeric anti-EGFR Z-domain conjugates for binding to the EGFR by a standard ELISA method and isothermal titration calorimetry.

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CHEM2021SABOURIN22557 CHEM

Preparation of Clickable Monomers Compatible with Automated PNA Synthesis

Type: Graduate
Author(s): Axel Sabourin Chemistry & Biochemistry Grace Newell Chemistry & Biochemistry
Advisor(s): Jean-Luc Montchamp Chemistry & Biochemistry
Location: Zoom Room 6, 01:18 PM

Fmoc-protected and propargyl-containing thymine and Cbz-protected cytosine monomers were synthesized for possible use in the pre- or post-functionalization of PNA oligomers via click chemistry. The monomers should be suitable for incorporation in normal automated solid phase PNA synthesis. The synthesis is suitable for the preparation of gram-quantities of monomers and uses reductive amination as the key step.

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CHEM2021SADAGOPAN61836 CHEM

Enhancing the therapeutic potential of heterocyclic ligands for treating Alzheimer's disease

Type: Undergraduate
Author(s): Nishanth Sadagopan Chemistry & Biochemistry Sugam Kharel Chemistry & Biochemistry Kristof Pota Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry
Location: Zoom Room 1, 01:58 PM

Alzheimer's disease is a neurodegenerative disorder that is characterized by amyloid-beta plaques, neurofibrillary tangles, and unregulated reactive oxygen species. The production of reactive oxygen species in the brain is exacerbated by an excess of free-metal ions in nervous tissue. Our team and others have shown a library of tetra-azamacrocycles to have the ability to scavenge free-metal ions and quench reactive oxygen species. These macrocyclic ligands have, thus, been considered as potential therapeutic agents for combatting Alzheimer’s disease. The ability of a neuro-active pharmaceutical to cross the blood-brain barrier is crucial to its pharmacological success and has proven to be a significant challenge to date in moving molecules from the bench to clinical treatment paradigms. The aim of this work is to enhance the pharmacological potential of these macrocyclic ligands. To accomplish this, computational analyses were performed on two tetra-azamacrocycles to predict their baseline blood-brain barrier permeability. The structures of these macrocycles were then modified with various moieties and analyzed via the same computational methods to predict their blood-brain barrier permeability potential. One target modification this project is focused on is the attachment of omega-3 fatty acids to these tetra-azamacrocycles. Omega-3 fatty acids have been shown to have beneficial anti-inflammatory properties in vivo and have the ability to assist in transporting molecules across the blood-brain barrier. Thus, the inclusion of these moieties to the structure of the Green Group ligands are attractive in regard to enhancing their pharmacological potential. To accomplish this attachment, the synthetic approach of one of the Green Group’s flagship tetra-azamacrocycles, OHPy-N3, had to be completely reimagined. New synthetic approaches and protection strategies were employed to achieve a suitable intermediate molecule primed for the addition omega-3 fatty acids. These novel synthetic methods and subsequent results are discussed in this work herein.

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CHEM2021SEGURA24832 CHEM

Synthesizing a Vaccine for the Treatment of Addiction to the Fentanyl Opioid

Type: Undergraduate
Author(s): Carolina Segura Biology Karen Winters Biology
Advisor(s): Jean-Luc Montchamp Chemistry & Biochemistry
Location: Zoom Room 1, 01:02 PM

The objective of this project is to make a vaccine that will negate the effects of the powerful opioid fentanyl in the long term. Fentanyl is a strong synthetic opioid that is 50 to 100 times more potent than morphine. According to the CDC, there were over 70,000 deaths due to street drug overdoses, which has increased in the last ten years. 40 % of these deaths are related to fentanyl overdoses, therefore it is imperative that approaches are developed to combat this alarming increase in deaths. The vaccine against fentanyl will be synthesized out of molecules that will take advantage of fentanyl’s amide functional group to be hydrolyzed into safe byproducts. Any patient that is administered with the vaccine, will not feel the effects of the opioid because the immune system will hydrolyze the drug as soon as it enters. This project will exploit the properties of both catalytic antibodies (CAbs) and transition state analogs. If the molecule resembles the transition-state of fentanyl hydrolysis, then the antibodies can cleave the fentanyl in a fast and efficient manner due to their catalytic properties. Therefore, after immunization, a person who is addicted to fentanyl would no longer feel the effects of the opioid because it will be degraded as soon as an immune response is triggered, creating a long-term possible solution to one factor of the “opioid crisis.”

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CHEM2021SHERMAN26246 CHEM

Practical Synthesis of Alkenyl Phosphorus Compunds

Type: Undergraduate
Author(s): Emily Sherman Chemistry & Biochemistry
Advisor(s): Jean-Luc Montchamp Chemistry & Biochemistry Benjamin Janesko Chemistry & Biochemistry Anne VanBeber Nutritional Sciences
Location: Zoom Room 2, 03:27 PM

Alkenyl phosphorus compounds appear in multiple industrial products, from flame retardants to fungicides. Although several methods are available to synthesize these compounds, many require expensive catalysts, inaccessible starting materials, or multi-steps sequences. In response to these issues, this project sought to develop an efficient, two-step method to synthesize alkenyl phosphorus compounds from simple ketones. We compare acid and base catalysts and find both are effective in the first reaction step; furthermore, a one-pot reaction provides comparable yields to the reactions conducted with a purified intermediate. These findings lay the foundation for the exploration of more complex substrates, including those utilized in industrial applications.

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CHEM2021VEALS38707 CHEM

Synthesis and Characterization of an Iodo-substituted Macrocyclic Complex: Comparison of Pyridine Modification

Type: Undergraduate
Author(s): Diandria Veals Chemistry & Biochemistry
Advisor(s): Kayla Green Chemistry & Biochemistry
Location: Zoom Room 1, 03:03 PM

Pyridine macrocycles have useful applications due to their ability to complex with metals. A library of substituted pyridine macrocycles exists along with how modifications at Carbon 4 impact compound reactivity. Despite literature about similar pyridine macrocycle structures, little is known about how an iodo-substituted pyridine macrocycle will alter the properties of the compound when complexed to Copper. To understand the fundamental characteristics of an Iodo-substituted pyridine macrocycle, the ligand is synthesized followed by electronic environment analysis via 1H NMR. Ultraviolet-Visible Spectroscopy is used to verify ligand complexation with Copper (II) metal followed by X-ray diffraction to determine metal binding nature of the complex. Cyclic Voltammetry analysis is used to support the theory that the iodo functional group behaves as an electron withdrawing group. This compound serves as a comparison to explain the results of the Chloro-substituted pyridine macrocycle as well as a gateway molecule for the synthesis of new pyridine macrocycles.

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CHEM2020BUDENSIEK51413 CHEM

Fabrication and Characterization of Sub-Micron Plant-Derived Silicon Nanoparticles for Drug Delivery

Type: Undergraduate
Author(s): Hailey Budensiek Chemistry & Biochemistry
Advisor(s): Jeffery Coffer Chemistry & Biochemistry

Porous silicon nanoparticles exhibit great potential as drug delivery vectors due to their high surface-area-to-volume ratio allowing for increased efficacy of surface functionalization and therapeutic loading capabilities. This data set demonstrates the fabrication of a class of plant-derived materials which are sub-micron in size and capable of functionalization with primary amine groups through the addition of APTES.
The production of porous silicon particles (pSi) is achieved through magnesiothermic reduction of silica containing Tabasheer powder isolated from the nodal joints of the Bambuseae plant. Efficacy of this reduction is evaluated using techniques including X-ray diffraction and Energy-dispersive X-ray spectroscopy which show successful reduction of silica starting material to porous silicon.
High energy ball milling followed by reduction is used to produce pSi particles of sub-micrometer size while also allowing for a significantly higher yield (~90%) of material than previous methods. Particle size is confirmed via electron microscopy and dynamic light scattering (DLS).
Following reduction, surface functionalization of silicon nanoparticles with primary amine groups was carried out using a 4% (v/v) solution of APTES in acetone. The evaluation of this functionalization was conducted using techniques including zeta potential and infrared spectroscopy (IR). Zeta potential values are found to be approximately -10 mV. This data demonstrates successful amino silanization.
The results achieved through these methods suggest successful fabrication of pSi nanoparticles and subsequent functionalization for future use as a drug delivery vector.

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CHEM2020GOEHRING48218 CHEM

Creating Biocompatible Polymers Loaded With Porous Silicon Potentially For Drug Delivery

Type: Undergraduate
Author(s): Lexi Goehring Chemistry & Biochemistry
Advisor(s): Jeff Coffer Chemistry & Biochemistry

Drug delivery is the process by which medications are administered to the body. This is complex due to the difficulty of determining compounds that have the proper biocompatibility and permissibility to our human cells. Many medications are taken orally; however, there are advantages to administering medication subcutaneously or by inserting it in the inner corner of the eye. Porous films made out of biocompatible polymers provide a good platform for drug delivery as they have the ability to be loaded with plant derived porous Silicon. Functionalizing the porous silicon using (3-aminopropyl)triethoxysilane and glutaraldehyde can be done in an attempt to covalently attach particles to the film which is important for embedding them into the pores of the film. Porous silicon has biocompatible properties and can be loaded with drugs then modified to alter the release of those drugs in the body. This method has the potential to be a useful drug delivery method due to the biocompatible and biodegradable properties of the material and the ability to manipulate the material in order to maximize drug release.

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CHEM2020LE35772 CHEM

POROUS SILICON NANOTUBES AS POTENTIAL VECTORS FOR SMALL INTERFERING RNA DELIVERY

Type: Graduate
Author(s): Nguyen Le Chemistry & Biochemistry
Advisor(s): Jeffery Coffer Chemistry & Biochemistry Giridhar Akkaraju Biology

In cancer therapy, nucleic acid-based therapeutic strategies have been extensively investigated to suppress mutated gene expression, thereby inhibiting cancer cell growth. Among the approaches, small interfering (siRNA)-mediated gene silencing has been envisaged as a promising therapeutic approach to silence specific gene expression by targeting mRNA of the unwanted gene for degradation, thereby readily controlling cellular functions. However, delivery of small interfering RNA (siRNA) has been known to encounter multiple challenging barriers, such as blood circulation and cellular internalization, thus limiting the potential merits of this therapeutic strategy. While non-viral vectors have been preferred owing in part to better immune system compatibilities, porous silicon (pSi) with various geometric shapes (e.g. platelet and discoid) have recently been demonstrated as exceptional delivery carriers of siRNA in various disease models. Here our initial in vitro studies show that silicon in a unique one-dimensional porous nanotube structure (pSiNTs) can serve as a promising vector for delivery of siRNA to limit target gene expression, thereby expanding the library of possible nanostructures of Si in delivery of siRNA.
In this work, we demonstrate that pSiNTs after being functionalized with 3-(aminopropyl)triethoxysilane (APTES) can deliver enhanced green fluorescence protein (EGFP)-targeting-siRNA via electrostatic conjugation and suppress EGFP expression in HeLa cervical cancer cells by up to 50%. Cytocompatibility and biodegradation of the functionalized pSiNT matrix upon siRNA delivery are characterized by ATP quantification assays (CellTiter Glo) and Transmission Electron Microscopy imaging (TEM) respectively. These results encourage further development of pSiNTs in therapeutic applications.

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CHEM2020SEGURA63908 CHEM

Synthesizing a vaccine for the treatment of addiction to the fentanyl opioid

Type: Undergraduate
Author(s): Carolina Segura Biology
Advisor(s): Jean-Luc Montchamp Chemistry & Biochemistry

The objective of this project is to make a vaccine that will negate the effects of the powerful opioid fentanyl in the long term. Fentanyl is a strong synthetic opioid that is 50 to 100 times more potent than morphine. According to the CDC, there were over 70,000 deaths due to street drug overdoses, which has increased in the last ten years. 40 % of these deaths are related to fentanyl overdoses, therefore it is imperative that approaches are developed to combat this alarming increase in deaths. The vaccine against fentanyl will be synthesized out of molecules that will take advantage of fentanyl’s amide functional group to be hydrolyzed into safe byproducts. Any patient that is administered with the vaccine, will not feel the effects of the opioid because the immune system will hydrolyze the drug as soon as it enters. This project will exploit the properties of both catalytic antibodies (CAbs) and transition state analogs. The Cabs will trigger an immune response to attract phagocytic cells, such as macrophages to phagocytose pathogens and eliminate them from the system. However, if the molecule resembles the transition-state of fentanyl hydrolysis, then the antibodies can cleave the fentanyl in a fast and efficient manner due to their catalytic properties. Therefore, after immunization, a person who is addicted to fentanyl would no longer feel the effects of the opioid because it will be degraded as an immune response is triggered, creating a long-term possible solution to one factor of the “opioid crisis.”

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CHEM2019BEERI11498 CHEM

Using Surface Polymer Networks to Connect DSPEC Components for a High Solar Energy Conversion Efficiency

Type: Graduate
Author(s): Debora Beeri Chemistry & Biochemistry
Advisor(s): Benjamin Sherman Chemistry & Biochemistry
Location: Session: 1; Basement; Table Number: 5

presentation location

It is extremely important in our age to look for alternative, more environmentally favorable energy sources. The Sun is a largely unused and widely available energy source to power human industry which can be utilized in different ways. Photovoltaic cells directly convert solar energy to electricity but only provide power when illuminated. Supplying solar-sourced energy during night hours and inclement weather requires conversion to another form, for instance into chemical fuel by means of water splitting into oxygen and hydrogen. This strategy, inspired by natural photosynthesis, is currently a promising and actively researched approach. However, achieving a high energy conversion efficiency, which is essential for industrial implantation of the method, remains a primary goal.
A Dye-Sensitized Photoelectrochemical Solar Cell (DSPEC) is specifically designed for using solar energy to generate hydrogen from water. We are pursuing the formation of photoanodes with polymer surface coatings prepared by electropolymerization. The polymer interfaces are designed to promote directional electron transfer at the interface, thereby resulting in a better solar energy conversion efficiency. The structure of the surface polymer enables the incorporation of catalyst units to the interface. To this end, we have prepared several novel iridium-oxide nanoparticle suspensions, using two different synthetic methods, to serve as the water-oxidation catalysts in our system. During the synthesis, the nanoparticles are functionalized with specific capping groups that contain terminal double bonds, through which they can be incorporated to the surface polymer electrochemically. Using acrylic acid and acrylamide as small molecule precursors, electro-polymer coatings have been prepared on FTO (fluorine-doped tin oxide) surfaces. Future research work will involve the incorporation of functionalized iridium oxide nanoparticles in the poly(acrylic acid/acrylamide) films and the characterization of their catalytic activity toward water oxidation. The method will then be extended to tin-oxide and titanium-dioxide semiconductor electrodes for preparing photo-active interfaces.

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CHEM2019BLITCH45678 CHEM

Strong Hydrogen Bonds to Weak Bases: An Orbital Overlap Perspective

Type: Undergraduate
Author(s): Alexandra Blitch Chemistry & Biochemistry
Advisor(s): Benjamin Janesko Chemistry & Biochemistry
Location: Session: 2; 1st Floor; Table Number: 7

presentation location

Ion solvation is fundamental in biochemistry. It controls the biophysical processes of protein solubility, reactivity, phase separation, crystallization and informational equilibria involving proteins and polypeptides. Ion solvation depends on the solute-solvent interactions which are governed by the properties of solvent like polarity, hydrogen bonding and ability to donate or accept electrons. These properties are subject to Pearson’s hard–soft acid–base (HSAB) effect and are characterized as hardness and softness of solvents. There have been attempts to connect the solvent hardness-softness to molecular properties and some empirical scales have been devised like μ-scale, DS scale and difference between the IR wavenumber shift of the C-I stretch of ICN and the O-H stretch of phenol. Only limited attempts have been reported to correlate the properties of solvents obtained from quantum chemical calculation to these empirical scales of solvent hardness-softness.

Our new quantum chemical descriptor, Orbital Overlap Distance, D(r), measures the size of orbital lobes that best overlap with the wavefunction around an atom. Compact, chemically stable atoms in the molecule tend to have overlap distances smaller than chemically soft, unstable atoms. Plots of D(r) on computed molecular surfaces, like electron density or spin density, distinguishes and quantifies the chemically soft and hard regions of a molecule. We propose that D(r) can be considered in terms of HSAB theory in order to predict solvation of ions. Our initial studies exhibit that D(r) of many common solvents correlates well with Marcus’s empirical μ-scale of solvent softness. Our studies provide a direct method to estimate the softness-hardness of solvents by using standard quantum chemical calculations.

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CHEM2019BUCKINGHAM30657 CHEM

The Effects of Microgravity on the Creation of Nylon 6-10

Type: Undergraduate
Author(s): Allison Buckingham Chemistry & Biochemistry Keira Clotfelter Chemistry & Biochemistry Jack Dietz Biology Tommy Gifford Chemistry & Biochemistry Waylan Kisor Chemistry & Biochemistry
Advisor(s): Magnus Rittby Chemistry & Biochemistry
Location: Session: 2; Basement; Table Number: 9

presentation location

This is experiment is designed to test how Nylon 6-10 is constructed and responds in a microgravity environment. Nylon 6-10 is a very flexible fiber. It consists of two chemicals called polypropylene and sebacoyl chloride to make the nano-structure for Nylon 6-10. We have developed several of ideas on what will happen to Nylon 6-10 in micro-gravity. We think that it will change the molecular structure of the Nylon 6-10 in micro-gravity for the better or worse. The good variable is that Nylon 6-10 might change into a very flexible, durable substance for many different applications both on Earth and in space. One concern we have is that Nylon 6-10 might change the molecular structure to not form any fibers or it might not dry by absorbing air molecules.

We decided to use Nylon 6-10 because of its overall construction. The industrial process for Nylon 6-10 is stronger and more flexible than Nylon 6-6. It is basically liquid rope. It can be used for repairs and manufacturing. It is an industrial chemical. A variety of products are created using Nylon 6-10, toothbrushes, paint brushes and even your underwear. It is a very common product in many of different industries and is a very useful product. It behaves like nylon fiber for thread or can be used for manufacturing different tools such as epoxy or fiberglass. The industrial ideas are very extensive and there are many suppliers.

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CHEM2019CAREY22340 CHEM

Synthesis of Heterodimeric Macrocycles

Type: Undergraduate
Author(s): Hannah Carey Chemistry & Biochemistry Jason Mars Chemistry & Biochemistry
Advisor(s): Eric Simanek Chemistry & Biochemistry
Location: Session: 1; 2nd Floor; Table Number: 5

presentation location

Recent trends in drug discovery research are directed at targeting protein-protein interactions. Blocking these interactions could be an effective strategy for treatment. Here, the synthesis of a macrocycle, a large ring-shaped molecule that is the same size as many protein-protein interaction sites, is described. The synthesis relies on the preparation of two different, crescent-shaped molecules through short, multistep syntheses. When these two molecules are combined together and subjected to acid to reveal reactive groups, a spontaneous assembly process occurs. The macrocycle is characterized by conventional methods including 1H NMR (which reveals a diagnostic signal for cyclization), 13C NMR, and mass spectrometry.

(Presentation is private)