In chemistry, cyclic compounds of twelve or more atoms are considered macrocycles. Many bioactive, natural products containing macrocycles have been isolated and synthesized. Still, construction of macrocycles is usually considered a challenging step in their synthesis. Here, a route to different-sized macrocycles is described. These macrocycles arise from spontaneous cyclization of two identical subunits comprising a central triazine displaying both a masked aldehyde and hydrazine group. The aldehyde portion is presented on a linker that can comprise varying number of carbons. By varying this linker, macrocycles of 22, 24, and 26 atoms have been prepared. Future study focuses on probing macrocycle size with increasingly larger linkers.

Room-temperature ionic liquids and deep-eutectic solvents have become unique and almost indispensible materials for various areas of sciences, medicine and engineering. The ability to engineer media with desired properties favorably distinguishes these solvents from traditionally used molecular solvents.

This poster will describe our ongoing efforts on designing various types of ionic, eutectic systems as well as approaches towards modulating their phase transitions. Studies related to controlling the self-assembly process of various solutes in this type of media will also be presented.

This project will entail assessing several varieties of common and heirloom corn from throughout Texas to identify sugar (and thus alcohol) content.
After obtaining cereal samples from a local distillery, the cereals will be processed by mashing and fermenting.
The resulting mashes will be measured for pH and S.G., then analyzed through chromatography using HPLC-RID. These samples of corn will be assessed for variations in sugar yield, both and composition and quantification. After fermentation, the HPLC-RID will be used for chromatographic analysis of ethanol concentration. Ultimately, this will provide information on the most promising corn varieties, and expose their potential as a future staples of this partner distillery.

The cost of reagents and catalysts employed in synthetic methodologies developed in academia is very rarely discussed. Yet these costs are very real as they represent a significant portion of any grant proposal budget. The Cost of Academic Methodologies (CAM) is a novel concept, which should be considered when evaluating synthetic methodologies. CAM will allow for one to quantitatively evaluate with a numerical value a particular synthetic methodology that prepares a particular product. CAM will allow for a comparison among distinctly different reactions conditions, reagents, catalytic versus stoichiometric systems, etc. Cost considerations are almost always avoided in academic publications; however CAM is a parameter that can be useful to gauge seemingly non-comparable methodologies. Unlike specious or poorly-defined considerations often seen in manuscripts, such as “harshness” of conditions, “metal-free”, “precious metals are expensive”, etc., the CAM parameter is a real, tangible, aspect of academic methodologies, which is applicable to any chemical reaction.

Oxidative stress in the brain is a known contributor to the development of neurodegenerative diseases, including Alzheimer’s. The focus of this project is to target the amyloid-β plaque formations and reactive oxygen species (ROS) derived from mis-regulated metal-ions that lead to disease-causing oxidative stress. The present investigation measures both the antioxidant reactivity and metal chelating ability of 1,4,11,13-tetra-aza-bis(2,6-pyridinophane)-8,17-ol (L4).  L4 contains two radical scavenging pyridol groups along with a metal-binding nitrogen rich ligand system.  It was hypothesized that increasing the number of pyridol groups on the ligands in our small molecule library would increase the radical scavenging activity, which in turn may provide cells protection from oxidative stress.  The radical scavenging ability of L4 was quantified using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay. This was compared to other radical scavenging small molecules to evaluate the effect of the additional radical scavenging group on the antioxidant activity.  The interaction of L4 with redox active metal-ions such as copper(II) was also evaluated using the coumarin-3-carboxylic acid (CCA) assay to show the molecule’s ability to target mis-regulated metal-ions in diseased tissues. With the end goal being to develop a potential biological therapeutic agent, metabolic stability studies were also performed.

The combination of inorganic porous silicon (pSi) and flexible biocompatible polymers has been shown to yield more beneficial hybrid scaffolds for tissue engineering (i.e. use of synthetic materials to facilitate healing). PSi has a variety of tunable properties, including pore size, pore volume and non-toxic degradation. The addition of a biocompatible polymer such as polycaprolactone (PCL) can provide control over shape and serve as an additional drug delivery component.
In this work, composite materials consisting of oxidized porous silicon (ox-pSi) with a particle size of ~ 30 μm and pore size of 40-100 nm and PCL porous fibers. Porous fibers were fabricated using an electrospinning method into sheets of desired thickness (0.1-0.4 mm), fiber diameter 3-4 μm, and fiber pore size 300-500 nm. Ox-pSi particles previously loaded with the anticancer drug-camptothecin (CPT) were placed between two sheets (6 mm in diameter each) and sealed at the edges, resulting in ~65% loading of ox-pSi. Drug release from the ox-pSi particles alone and ox-pSi/porous PCL fiber composites was monitored fluorometrically in phosphate buffered saline (PBS), showing a distinct release profile for each material.
Ox-pSi/p-PCL fiber composites release a CPT payload in accordance with the Higuchi release model and showed a significant decrease in burst effect compared to ox-pSi particles only. In addition, composite evolution after 5 weeks in PBS at 37 oC was examined using gravimetry, differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM). Overall weight loss of the composites was about 50%, mainly attributed to pSi particles dissolution and some polymer hydrolysis. Preliminary DSC results show that high surface area porous PCL fibers are less crystalline compared to solid PCL fibers, suggesting a faster hydrolysis route.

Europium contrast agents have been extensively investigated as an alternative to typical Gd3+ species for imaging. This is due to the dual imaging modalities which can accessed dependent on the oxidation state of the europium metal center (T1 or PARACEST). To achieve these functionalities, the europium containing complex must be stable enough to support both oxidation states (+3 and +2). In collaboration with UTSW, an electrochemical investigation was completed to understand the effects of the ligand environment on the metal center as a direct result of glycine modification to the ligand scaffold, DOTA. Increasing amide functionalities in close proximity to the europium core result in a positive shift in the potential in comparison to the acetate arms associated with DOTA. Furthermore, the addition of the glycine moiety to the pendant arms results in redox activity of the ligand itself, making the ligand non-innocent in nature. Additionally, a crystal structure of Eu4 (the tetraglycinate DOTA derivative) was obtained and compared to known lanthanide complexes.

Non-conventional solvents, such as room-temperature ionic liquids and deep-eutectic solvents, have attracted a lot of attention in recent years due their diverse applications in various areas of sciences, medicine and engineering. The ability to control physical properties of these solvents by simply adjusting their structure and/or the ratio of the components favorably distinguishes ionic and eutectic solvents from traditionally used molecular solvents as it allows to custom design specific types of media for given applications.

This presentation will highlight our efforts on various aspects of the synthesis of ionic liquids and deep-eutectic solvents as well as it will describe our investigations on the physical properties and nanostructural organization of these liquids using environmental probes, such as those that feature BODIPY and aza-BODIPY motifs. In addition, our initial studies on the design of multiphase systems that utilize ionic, eutectic and molecular solvents will be presented.

Cerium (IV) oxide, or CeO2, nanomaterials have displayed antioxidant and enzyme mimetic activities due to a Ce3+/Ce4+ redox capability enhanced through oxygen vacancies and mobility. Tri-valent, fluorescent ions such as Eu3+ increase the Ce3+/Ce4+ ratio and oxygen vacancy concentration, while contributing fluorescent properties to the nanomaterial. The combination of these attributes make europium doped cerium oxide (EuCeO¬2) nanomaterials appealing candidates for various biological applications.
To complement our earlier efforts on the synthesis and properties of EuCeO2 nanowires, nanorods, and nanocubes, this presentation addresses a new, complementary structure, EuCeO2 nanotubes. The nanotubes are prepared via deposition and subsequent oxidation of Eu-doped Ce(OH)3 to form a EuCeO2 shell on sacrificial ZnO nanowires.
Previous synthetic routes to CeO2 nanotubes have been reported featuring carbon nanotubes as sacrificial templates, the etching of cerium-based nanorods, and other less-common methods . These routes have struggled with clear evidence for distinct nanotube formation, as well as control over nanotube dimensions. Our use of a ZnO core allows for facile manipulation of inner diameter and length of the nanotube following etching of the core.
The synthesized nanotubes were characterized using scanning and transmission microscopy (SEM and TEM) for morphology, energy dispersive x-ray (EDX) for elemental composition, and photoluminescence to track europium fluorescence. Synthesized nanotubes had inner diameters from 40 nm to 200 nm, based on the ZnO core. Following synthesis and characterization, the nanotubes will be tested for use as a drug delivery vector, using ibuprofen as a model.

This project is aimed to modify a leucyl-tRNA synthetase (LeuRS) to incorporate fluorescent amino acids into proteins to produce fluorescent proteins in living cells. Fluorescent proteins are useful because they are easily analyzed and tracked in living organisms. In a small scale, we successfully prepared the library of LeuRS variants in which five amino acids are randomized in the leucine-binding site of a functional LeuRS without its editing domain. Currently, we are working on a large scale production of viable bacterial cells that cover the whole diversity of library (at least 34 million different LeuRS molecules). Initially, we attempted two-step process in which an N-terminal library fragment (for two randomized amino acids) is generated first and a C-terminal fragment (for three randomized amino acids) is added later. However, this two-step cloning process did not produce enough viable cells to cover all the possible variants. In a new approach, a complete library of LeuRS will be produced by overlapping extension PCR and introduced to E. coli in a single step to ensure highest possible transformation efficiency. Consequently, the library of LeuRS variants will be subject to a genetic selection experiment to obtain LeuRS variants that incorporate only fluorescent amino acids into proteins.

Diffusiophoresis is the migration of a relatively large particle (e.g., protein, polymer, nanoparticle) induced by a gradient of salt concentration. The salt-induced diffusiophoresis of lysozyme, a model protein, at pH 4.5 and 25 °C was examined as a function of salt concentration for three chloride salts: NaCl, KCl and MgCl2. Diffusiophoresis coefficients were theoretically extracted from experimental multicomponent diffusion data by applying irreversible thermodynamics. A selected mass-transfer process was theoretically examined to show that concentration gradients of MgCl2 produce significant lysozyme diffusiophoresis. The dependence of lysozyme diffusiophoresis on salt nature was theoretically examined and linked to protein charge. The effect of salt type on hydrogen-ion titration curves was experimentally characterized to understand the role of salt nature on protein charge. Our findings indicate that diffusiophoresis may be exploited for diffusion-based separation of proteins in the presence of salt concentration gradients and for the enhancement of protein adsorption onto solid surfaces relevant to biosensing applications.

The randomization of 11 bases in the theophylline-binding domain generated a library containing millions of different theophylline riboswitch variants. The dual genetic selection of this molecular library successfully led to the identification of a caffeine-specific synthetic riboswitch. When a chloramphenicol-resistance gene was expressed under control of this caffeine riboswitch, E. coli cells showed chloramphenicol resistance only in the presence of caffeine. For a colorimetric or fluorescence assay, the caffeine riboswitch gene was inserted upstream of the B-galactosidase (LacZ) or green fluorescence protein (GFP) gene, respectively. When tested with various concentrations of caffeine, the enzymatic activity of LacZ or the fluorescence intensity of GFP was proportional to the amount of caffeine, clearly indicating the caffeine-dependent gene regulation by the caffeine riboswitch. The caffeine synthetic riboswitch can be further developed as a biosensor to detect caffeine in complex biological samples such as urine and blood.

Abacavir or Ziagen, is an antiretroviral medicine that is used in conjunction with other
medicines to treat HIV. Although it is not a cure, it has been clinically proven to be
effective in diminishing the rate of HIV replication. The synthetic process of creating
Abacavir is both timely and costly, so therefore a new synthetic process has been
created to generate a chemical analog (specifically a triazine derivative) that is cheaper
to produce that can be if not potentially more chemically effective than Abacavir. Once
the analog is produced, a series of analytical tests will be done on a micro organismic
level to determine if the analog is both effective and safe enough to be used in human
clinical studies further down the road.

The pyrrolophenanthridone alkaloid pratosine is a natural product related to hippadine, which is known to be a powerful but reversible inhibitor of spermatogenesis in rats. Hippadine has also shown cardiovascular as well as anticancer activity. Given the structural similarities between the two molecules, it is expected that pratosine and hippadine will demonstrate similar biological effects. Our work toward a laboratory synthesis of pratosine will facilitate large-scale production thus affording sufficient quantities of the material for a complete pharmacological study of its properties. Although we have a synthetic plan for preparing pratosine, several reactions have failed due to solubility problems. This research focuses on solving these problems by using an alternate starting material. The commercially available compound vanillin, which is extracted from vanilla beans, is a simple and inexpensive aldehyde with an appropriate structure for attaching other groups that should improve the solubility properties of several of the synthetic intermediates. Our goal is to find a specific substituent that will provide the required characteristics but which can also be removed later to generate the final product.

Porous silicon (pSi) is a unique nanostructured form of the elemental semiconductor Si. Due to its useful properties governed by its surface chemistry and porous morphology, pSi has been studied in the last few decades in diverse fields extending from electronic device technology to bio-relevant applications.1 Recently, one-dimensional porous nanotubes based on elemental Si (pSiNTs) with a tunable structure (sidewalls, inner void space and lengths) have been successfully synthesized.2 The well-defined structure of pSiNTs offers ample opportunities to study newly emerging properties of this material and innovative applications in multiple areas. For example, recent reports have revealed the use of SiNTs as an efficient template for loading superparamagnetic nanoparticles (Fe3O4), lithium storage and cycling, as well as acting as a template for formation of organometal perovskite nanostructures.3-5
Platinum (Pt) nanoparticles, both free-standing as well as anchored on various surfaces, have attracted widespread attention in nanocatalysis, electronics, and chemotherapeutics.6 In this work, it is suggested that pSiNTs after being functionalized with 3-(aminopropyl)triethoxysilane (APTES) can serve as a platform for Pt nanocrystal (Pt NC) formation. Particularly, incubation of APTES-functionalized SiNTs in potassium tetrachloroplatinate (II) (K2PtCl4) solution under ambient conditions subsequently yields Pt nanoclusters with sizes ranging from 1-3 nm on SiNTs. From high-resolution transmission electron microscopy (HRTEM), nanocrystals with characteristic lattice spacings associated with Pt (d = 0.21 nm) are observed on the nanotubes. The amount of Pt deposited on SiNTs can be sensitively tuned from 20-60 wt% (characterized by TEM Energy Dispersive X-ray Analysis, EDX) by varying concentration of K2PtCl4 and immersion time in this Pt salt precursor.
These findings suggest a new approach to prepare Pt NCs that are of potential benefit to a broad number of applications by using pSiNTs as a template. Further investigations into the properties of the newly discovered Pt NCs-SiNT composites are imperative to evaluate useful applications of this material.
REFERENCES
[1] Porous Silicon for Biomedical Applications, H. Santos, Ed. Cambridge: Woodhead Publishing, 2014.
[2] X. Huang, R. Gonzalez-Rodriguez, R. Rich, Z. Gryczynski, J.L. Coffer, Chem. Commun., 2013, 49, 5760-5762.
[3] P. Granitzer, K. Rumpf, R. Gonzalez, J. Coffer, M. Reissner, Nanoscale Res. Lett. 2014, 9, 413.
[4] R. Gonzalez-Rodriguez, N. Arad-Vosk, N. Rozenfeld, A. Sa'ar, J. L. Coffer, Small, 2016, 12, 4477-4480.
[5] A. T. Tesfaye, R. Gonzalez, J. L. Coffer, T. Djenizian, ACS Appl. Mater. Interfaces, 2015, 7, 20495-20498.
[6] A. Chen, and P. Holt-Hindle, Chem. Rev., 2010, 110, 3767-3804.

Urea is a low-cost, water-soluble fertilizer that is used as the major source of nitrogen in agricultural production. However, the problem with leaching, in which urea in soil is rapidly washed away through rain and irrigation, results in inefficiency in nutrient absorption, low crop yield, poor harvest, and economic failure for farmers (Broadbent 1958), as well as the environmental pollution of groundwater by the release of excessive amounts of nitrate, which adversely affects this non-rechargeable water source. Therefore, recent research attempts to design a suitable system to prolong the release of urea from water in soil to improve soil fertility, agricultural economy, and ground water protection. A prospective approach is to integrate urea into a stable matrix that releases the desired material with an optimal time window.

Porous Silicon (pSi) has been studied as the material of diverse interest, due to its surface chemistry and porous morphology that has promoted many nanotechnology advances, in conjunction with its biocompatibility and biodegradability (Canham 2014). Since pSi degrades slowly in aqueous media and does not react with the soil component, it is selected to be a possible matrix for sustaining urea release. pSi is believed to interact with urea via hydrogen bonds (via surface silanol species), and thus its porous structure is the key to trap urea particles for relatively long periods in water, while exposing the fertilizer to plants. This bioactive pSi material is produced from the eco-friendly Tabasheer-derived silica, during which pSi porosity is maintained (Kalluri et al. 2016). Loading of urea into pSi is carried out using ethanol as a solvent, with theoretical loadings ranging from 27-33% of the composite mass. Release kinetics of urea from water is currently being investigated using highly sensitive colorimetric assay that applies Jung’s method (Jung et al. 1975).

The urea-loaded pSi prepared in these experiments were characterized using several different techniques. X-ray diffraction (XRD) evaluates the crystallinity of pSi after fabrication, with the presence of three peaks consistent with a cubic unit cell structure [Si (111), (220), and (311)]. Thermal gravimetric analysis (TGA) gives the mass loss percentage between melting (132oC) and boiling (203oC) points of urea, which represents the practical loading of urea in a given sample. The results deviate 1-2% from the theoretical loading percentage. TGA also shows the stability of the composite over two months at room temperature, with the recent loading measurement analyses consistent with the previous ones. Differential scanning calorimetry (DSC) analysis confirms that the urea is incorporated in the pSi matrix. Loading and characterization studies were conducted in triplicate to ensure reproducibility of results.

Atomic partial charges obtained from computed wavefunctions are widely used for interpreting quantum chemistry simulations and chemical reactivities of molecules, solids, surfaces, and nanoparticles. In many cases, partial charge alone gives an incomplete picture of reactivity: PhS(-) is a better nucleophile compared to PhO(-) in SN2 reactions with MeI, though PhO(-) has a more negative charge on the nucleophilic atom, the carbons of benzene and cyclobutadiene, or those of diamond, graphene, and C60, possess nearly identical partial charges and very different reactivities, deprotonated amides perform nucleophilic attack via the less negative nitrogen, rather than the more negative oxygen, in anionic cyclization of o-alkynyl benzamides, halide anions F(-), Cl(-), Br(-) and I(-) have identical charges but different nucleophilicities, carbons in aromatic benzene and anti-aromatic cyclobutadiene have nearly identical partial charges, but different reactivities. Our atomic overlap distance complements computed partial charges by measuring the size of orbital lobes that best overlap with the wavefunction around an atom. Compact, chemically stable atoms tend to have overlap distances smaller than chemically soft, unstable atoms. Combining atomic charges and overlap distances captures trends in aromaticity, nucleophilicity, allotrope stability, and substituent effects. Applications to recent experiments in organic chemistry (counterintuitive Lewis base stabilization of alkenyl anions in anionic cyclization), nanomaterials chemistry (facile doping of the central atom in Au7 hexagons) and selective binding of ligands in proteins illustrate this combination’s predictive power.

Amaryllidaceae isoquinoline alkaloids, as well as their analogs, have long been of interest in research for drug discovery due to their biologically active nature. Many of these compounds have been found to be anti-tumor agents.1 Moreover, there have also been studies that show the effectiveness of these molecules against diseases such as Yellow Fever and other RNA-containing flaviviruses.2 Though these compounds are pharmaceutical drug prospects, their low natural abundance lowers that potential.3 For this reason, many synthetic chemists have pursued novel routes to synthesize a wide variety of these compounds.
Techniques toward the synthesis of Pancratistatin-type natural products are presented herein. Manipulations were tested and optimized on a model system to save both time and funds while developing a synthetic pathway to be utilized in the formation of more complex compounds. Setbacks such as controlling the stereochemistry of a tetrasubstituted alkene reduction have been encountered. However, adjustments are being made to avoid such difficulties. Ideally, the proposed scheme will ultimately allow for the synthesis of multiple biologically active Phenanthridone analogs.

A library of novel tetra-aza macrocyclic molecules, specifically 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene derivatives, capable of chelating metal ions in vivo have been synthesized. Applications of these complexes are currently being pursued as a 1) therapeutic focusing on radical scavenging and metal chelation and 2) diagnostic tool such as magnetic resonance imaging (MRI) contrast agents when complexed with specific metal ions. However, a full study of the electronic effects imparted by substitution to the pyridyl moiety (position 13) and the subsequent impact on the metal center have not been explored. The objective of the present study is to characterize metal complexes of four tetra-aza macrocyclic metal chelating molecules. The pyridyl functional groups studied include: A) unmodified pyridyl, B) p-hydroxyl, C) p-nitrile, and D) m-hydroxyl modified pyridyls on a pyclen base structure (position 13). Notable progress has been made in developing an optimal procedure for obtaining copper (II) complexes and will be presented. Analysis of the resulting copper (II) complex of the p-nitrile tetra-aza macrocycle indicate a six-coordinate metal center based on X-ray diffraction. UV-Visible spectroscopy and electrochemistry help to confirm donor strength among the ligand series as well as a comparison to other tetra-aza macrocycles. Ultimately, this project is focused on understanding the electronic contribution of these functional groups on the pyridine ring and the influence of the ligand and complexed systems as therapeutic and diagnostic agents.

Hippadine and pratosine are lycorine-type pharmacologically active Amaryllidaceae alkaloids. Various total syntheses of these natural products have been developed. However, most of these synthetic routes require prohibitively expensive materials and/or achieve yields that are subpar, making these schemes unlikely to be used in an industrial setting. Current research involves developing better synthetic methods for these two alkaloids starting with a 6,7-disubstituted isoquinoline. These syntheses are appealing since they utilize readily available starting materials and avoid expensive catalysts. The key step in the synthetic scheme centers around an intramolecular de Mayo photocyclization which involves a reaction between an alkene moiety in the isocarbostyril system and a 1,3-diketone (a functionalized tether on nitrogen), which forms a third ring in the structure of the molecule. When the photochemical reaction was attempted, an unexpected cyclic photoproduct was obtained; fortunately, this product is a cyclic hemiketal of the expected 1,5-dicarbonyl compound. A base-catalyzed aldol addition affords the final ring in the system; dehydration of this product affords a β-enone that can be transformed to a diene. Oxidation of the diene with DDQ affords the target natural products after simple chromatographic purification. This new synthetic pathway circumvents the need for catalysts that are either expensive or contain metals such as palladium or iridium; moreover, our method allows for the synthesis of various natural and unnatural alkaloids in high yields by modification of the N-tether.

Molecules previously developed by the Green Research Group (L2 and L3) have been shown to reduce reactive oxygen species (ROS) through multiple pathways of activity. Although unclear if ROS is the only source, Alzheimer’s disease and other neurodegenerative disorders are known to be initiated from the formation of these ROS. For these molecules to appropriately execute their antioxidant and radical scavenging ability, they must enter into the brain where the damaging ROS are located. The blood brain barrier (BBB) is a natural obstacle that prevents toxins and infections from reaching the brain. The L2 and L3 ligands must penetrate this barrier to be in the desired site of action to reduce the number of ROS. Addition of a glucose moiety to other therapeutic molecules has been shown to increase permeability across the BBB. The target of this project is to enhance these synthetic pathways of glycosylation and increase product yield. Initially, direct addition of the glucose moiety to the L2 and L3 molecules was achieved. However, challenges with purification techniques suggested a different route to purification or design should be considered and one new route is presented here. With L2 and L3 being inherently hydrophilic, addition of an aliphatic chain to the hydroxyl group of L2 or L3 should increase the hydrophobicity of the molecule allowing for different purification techniques, which can ultimately be glycosylated to give purified desired compounds.

A recent and promising development in solar energy involves a class of materials known as organometal halide perovskites, capable of efficiencies (>20%) comparable to the current industry standard of silicon. These materials also demonstrate strong light emission, a key property associated with energy-efficient sources of lighting, suggesting potential applications in light-emitting devices such as light-emitting diodes (LED). The goal of this project was to investigate the fundamental photoluminescence (PL) properties of perovskites housed in a nanoporous material known as semiconducting porous silicon (pSi).

pSi provides a nanoscale template to control the growth of the light-emitting perovskite structure and is an electrically-responsive host matrix, ideally regulating the flow of charge to/from the perovskite. Samples were prepared within the pores of surface oxidized pSi and hydride-terminated pSi, each with a mesoporous width in the 5 – 50 nm range. The perovskite-loaded pSi was fabricated through solution-loading of perovskite precursors into warmed pSi (60ºC), removal of excess reactant solution, and drying. While perovskites can feature a wide range of halide compositions (including mixed halides), this research thus far has focused on methylammonium lead iodide (MAPbI3) perovskite.

These perovskite nanostructures formed within pSi were characterized using a variety of techniques. Following synthesis, the stability of each prepared sample was monitored for 3 weeks through tracking its relative photoluminescence intensity at its maximum value. Perovskite morphology was evaluated by SEM (scanning electron microscope) and TEM (transmission electron microscope) imaging, crystalline structure was evaluated by XRD (x-ray powder diffraction), and elemental analysis was evaluated by EDX (energy-dispersive x-ray spectroscopy).

In this study, SEM imaging showed consistent perovskite particle size and ununiformed perovskite infiltration. It is found that the emission intensity for MAPbI3 formed within hydride-terminated pSi (at ~730nm) and oxidized pSi (at ~740nm) were relatively stable over a 3 week period, but the emission intensity for perovskite microrods formed in the absence of any pSi template actually decreased over time. More detailed measurements of the long term stability of these new nanoscale materials are currently under evaluation.

Significant increases in average life expectancy in the last century have brought a growth in human illnesses related to aging: chronic wounds, bone diseases, eye diseases and cancer. In this work, we demonstrate fabrication of biodegradable polymer scaffolds that can be used for drug delivery and tissue engineering to treat the above-mentioned ailments. Tissue engineering can be defined as the use of a combination of engineering and materials methods and appropriate biochemical factors to improve or replace biological tissues.
This project includes fabrication of solid and porous fibers from the biocompatible PCL polymer. This polymer is currently used for surgical sutures, nerve guides and three-dimensional scaffolds for use in tissue engineering. The drug release rate is faster when it is loaded into porous PCL fibers compared to solid PCL fibers, creating an advantage for porous fiber fabrication. Use of a technique known as electrospinning of a solution of PCL and chloroform results in solid fibers that are 4 (± 2.0) micrometers (μm) in diameter. The porous fiber scaffolds are fabricated using a 50% weight of PCL compared to volume of solvent (w/v) solution prepared in a mixture of solvents 9:1 dichloromethane (DCM):dimethyl sulfoxide (DMSO) and 60% w/v PCL in 8:2 DCM:DMSO. The porous fibers are collected at 0-5 oC with a pore size of 50.0 (± 10.0) nanmoeters (nm) and fiber diameter of 3.0 (± 1.0) μm. The porosity for 50% w/v PCL and 60% w/v PCL fibers ranges from 40-50%.
Fiber surface morphology is characterized using field emission scanning electron microscopy (FESEM). In addition, the melting temperature and percent crystallinity are determined via differential scanning calorimetry (DSC). The melting temperature was collected of PCL bulk, 30%w/w PCL solid fibers, 50% w/v PCL and 60% w/v PCL. The crystallinity of PCL in solid fiber and porous fiber forms ranges from 52-55%, compared to the 60% crystallinity of PCL bulk. Solid PCL fibers showed to be more crystalline compared to porous PCL fibers, which in turn can effect the degradation time.
In order for these composites to be identified as a major technological advancement, the aging and degradation of the polymer scaffold must also be understood. The degradation of a given polymer matrix impacts the potential drug delivery behavior when testing in vitro. Degradation studies of the above mentioned materials are currently ongoing.

While cis/Z-substituted alkenes are usually less stable than their trans/E-substituted counterparts, the cis-2-butenyl anion shows a higher preference over the trans-isomer. Calculations suggest that the discrepancy is due to two cooperating effects: electrostatic interactions between the anionic center (C1) to the methyl group (C4) and coupling between the C=C pi* antibonding orbital and both the CH2 pz and CH3 C-H sigma bonds. Supporting the charge transfer is the fact that substitution on C1 with EDG stabilizes the cis more while substitution on C4 with EWG stabilizes the cis more. For the coupling interaction the C=C bond was stretched which increased the cis stabilization by lowering the pi* orbital energy and increasing the coupling between the lone pair on C1 and pi*.

Oxidative stress in the brain is a known contributor to the development of neurodegenerative diseases, including Alzheimer’s. The focus of this project is to target the amyloid-β plaque formations and reactive oxygen species (ROS) derived from misregulated metal-ions that lead to disease-causing oxidative stress. The present investigation is measuring the antioxidant reactivity of the new molecule L4. L4 contains two radical scavenging pyridol groups along with a metal-binding nitrogen rich ligand system. It was hypothesized that increasing the number of pyridol groups in our small molecule library would increase the radical scavenging activity, which in turn may provide cells protection from oxidative stress. The radical scavenging ability of L4 was quantified using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay and this was compared to other radical scavenging small molecules to evaluate the effect of the additional radical scavenging group on the antioxidant activity. The interaction of L4 with redox active metal-ions such as copper(II) was also evaluated to show the molecule’s ability to target misregulated metal-ions in diseased tissues.