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Organic metal halide perovskites (HPs) are attractive materials for a variety of electronic applications due to their low cost, tunable band gaps, excellent charge transport properties, and high photoluminescence efficiency. As such, HPs are being investigated for use in solar cells, photodetectors, X-ray detectors, light emitting diodes, field effect transistors, lasers, resistive random-access memory, etc. Currently the most popular metal used in HPs is lead, but the use of lead comes with the potential for heavy metal exposure. Tin-based perovskites offer a less hazardous alternative, but their optoelectronic properties lag behind those of lead and less work has been done to characterize them. In this work, we investigate Ruddlesden-Popper Phase (RPP) tin perovskites with phenethylammonium and its derivatives to determine how the structure of the A*-site cation impacts the optical and electronic properties.

Organic metal halide perovskites (HPs) are attractive materials for a variety of electronic applications due to their low cost, tunable band gaps, excellent charge transport properties, and high photoluminescence efficiency. As such, HPs are being investigated for use in solar cells, photodetectors, X-ray detectors, light emitting diodes, field effect transistors, lasers, resistive random-access memory, etc. Currently the most popular metal used in HPs is lead, but the use of lead comes with the potential for heavy metal exposure. Tin-based perovskites offer a less hazardous alternative, but their optoelectronic properties lag behind those of lead and less work has been done to characterize them. In this work, we investigate Ruddlesden-Popper Phase (RPP) tin perovskites with phenethylammonium and its derivatives to determine how the structure of the A*-site cation impacts the optical and electronic properties.

Lignin is a complex aromatic biopolymer and an important constituent in plant cell walls. The process of lignin biosynthesis, known as lignification, is poorly understood and challenging to study but has important implications in a variety of fields including sustainable energy, bioengineering, and materials science and is therefore of interest to pursue. In the final stage of lignification, H-, G-, and S-monolignols are oxidized by laccase and peroxidase enzymes to generate radical species that couple to form dimers and further oligomeric species to ultimately produce the lignin polymer. Biomimetic lignin model systems utilize in vitro oxidative coupling reactions as an important tool to further develop our understanding of this complex process. The goal of the first portion of this dissertation was to explore several aspects of monolignol oxidative coupling using high performance liquid chromatography (HPLC). These aspects included the study of relative reaction rates, both with respect to monolignol conversion and product formation, and the effects of solvent composition on product distribution. Electrospray ionization mass spectrometry (ESI-MS) was an important analytical tool for characterizing many coupling products, especially higher oligomeric compounds. The insights acquired from these experiments contributed valuable information towards a fuller understanding of the lignification process.

Plant secondary metabolites are a vital source of medicinally relevant compounds. These metabolites are involved in the plants’ highly dynamic chemical defense against environmental stressors such as UV light, predators, and pathogens. Elicitation is a process in which changes in plant secondary metabolism are induced by specific stressors to understand metabolic pathways involved in plant defense. The second portion of this dissertation focused on the study of metabolism, known as metabolomics. Methods development for sample preparation and data processing in untargeted metabolomics was applied to study elicitation of secondary metabolites in Lobelia Cardinalis hairy root cultures. This study specifically explored the potential of nanoparticles as a delivery system to enhance the elicitation effects of jasmonic acid. In this work, UHPLC-MS with high resolution accurate mass was used to evaluate the secondary metabolic response of L. Cardinalis hairy root cultures to jasmonic acid-loaded nanoparticles.

Lignin is a complex aromatic biopolymer and an important constituent in plant cell walls. The process of lignin biosynthesis, known as lignification, is poorly understood and challenging to study but has important implications in a variety of fields including sustainable energy, bioengineering, and materials science and is therefore of interest to pursue. In the final stage of lignification, H-, G-, and S-monolignols are oxidized by laccase and peroxidase enzymes to generate radical species that couple to form dimers and further oligomeric species to ultimately produce the lignin polymer. Biomimetic lignin model systems utilize in vitro oxidative coupling reactions as an important tool to further develop our understanding of this complex process. The goal of the first portion of this dissertation was to explore several aspects of monolignol oxidative coupling using high performance liquid chromatography (HPLC). These aspects included the study of relative reaction rates, both with respect to monolignol conversion and product formation, and the effects of solvent composition on product distribution. Electrospray ionization mass spectrometry (ESI-MS) was an important analytical tool for characterizing many coupling products, especially higher oligomeric compounds. The insights acquired from these experiments contributed valuable information towards a fuller understanding of the lignification process.

Plant secondary metabolites are a vital source of medicinally relevant compounds. These metabolites are involved in the plants’ highly dynamic chemical defense against environmental stressors such as UV light, predators, and pathogens. Elicitation is a process in which changes in plant secondary metabolism are induced by specific stressors to understand metabolic pathways involved in plant defense. The second portion of this dissertation focused on the study of metabolism, known as metabolomics. Methods development for sample preparation and data processing in untargeted metabolomics was applied to study elicitation of secondary metabolites in Lobelia Cardinalis hairy root cultures. This study specifically explored the potential of nanoparticles as a delivery system to enhance the elicitation effects of jasmonic acid. In this work, UHPLC-MS with high resolution accurate mass was used to evaluate the secondary metabolic response of L. Cardinalis hairy root cultures to jasmonic acid-loaded nanoparticles.

With the continuing rise in demand for energy, it is becoming increasingly necessary to invest more effort into the research and development of new materials that generate or harvest energy. One avenue of materials science is continued research into perovskites, a class of materials having a similar structure to its namesake mineral, which has seen use in piezoelectrics, photovoltaics, and sensors. An adaptation of perovskites; hybrid organic-inorganic materials/metalates, referred to here as HOIMs or just simply as halometalates, have been promising alternatives to traditional perovskites. Derived from the perovskite A2+B4+(X-2)3 formula, HOIMs following the A2+Bn+Xn+2 format where A represents the organic cation, B the metal cation, and X the halide anion are synthesized from a combination of organic and inorganic components which allows for deviations from the stricter crystal structure of the perovskites. These organic components allow for lower temperature requirements and solution processability, making them promising materials with a low barrier of entry. Because of this versatility in synthesis and structure, the corresponding tunability of their constituents provides an excellent avenue of approach for the development of novel, task-specific HOIMs the physical, optical and electronic properties of which could be carefully controlled for. While there has been and currently is research being done to elucidate the tuning of individual changes to the various cation and anion sites within halometalate materials there remains a need to combine these various approaches together into a cohesive manual for the design and fabrication of these materials for future use. The hypothesis upon which this work is structured lies in that tying together of the disparate structures which have been shown to exhibit tunability before. That is the ability to individually yet cotemporally alter specific structural characteristics of an HOIM in such a way as to select for a unique combination of performant traits, and in so doing show a verifiable, reproducible methodology. This work investigates several promising halometalate materials whose similar structures allow for simple, stepwise alterations with the intent of measuring the effect these changes have on their physical arrangement and nonlinear properties.

With the continuing rise in demand for energy, it is becoming increasingly necessary to invest more effort into the research and development of new materials that generate or harvest energy. One avenue of materials science is continued research into perovskites, a class of materials having a similar structure to its namesake mineral, which has seen use in piezoelectrics, photovoltaics, and sensors. An adaptation of perovskites; hybrid organic-inorganic materials/metalates, referred to here as HOIMs or just simply as halometalates, have been promising alternatives to traditional perovskites. Derived from the perovskite A2+B4+(X-2)3 formula, HOIMs following the A2+Bn+Xn+2 format where A represents the organic cation, B the metal cation, and X the halide anion are synthesized from a combination of organic and inorganic components which allows for deviations from the stricter crystal structure of the perovskites. These organic components allow for lower temperature requirements and solution processability, making them promising materials with a low barrier of entry. Because of this versatility in synthesis and structure, the corresponding tunability of their constituents provides an excellent avenue of approach for the development of novel, task-specific HOIMs the physical, optical and electronic properties of which could be carefully controlled for. While there has been and currently is research being done to elucidate the tuning of individual changes to the various cation and anion sites within halometalate materials there remains a need to combine these various approaches together into a cohesive manual for the design and fabrication of these materials for future use. The hypothesis upon which this work is structured lies in that tying together of the disparate structures which have been shown to exhibit tunability before. That is the ability to individually yet cotemporally alter specific structural characteristics of an HOIM in such a way as to select for a unique combination of performant traits, and in so doing show a verifiable, reproducible methodology. This work investigates several promising halometalate materials whose similar structures allow for simple, stepwise alterations with the intent of measuring the effect these changes have on their physical arrangement and nonlinear properties.

Graphene and other two-dimensional (2D) materials exhibit remarkable electronic, thermal, and optical properties that can be tailored by material selection, structural design, and the incorporation of transition metals. This study explores graphite intercalation compounds (GIC) via sonication techniques and extends the approach to alternative carbon allotropes. This work also highlights our advancements on hexagonal boron nitride (hBN), a wide band gap insulator structurally related to graphene, and advancement of intercalation via sonication at ambient temperature.

Additionally, the manipulation of ferromagnetic 2D materials, including chromium (III) iodide and chromium sulfur bromide, is demonstrated through electron beam patterning, highlighting advancements in artificial spin lattices and spin ices.

These works are characterized using PXRD, TEM, and STEM coupled with EDS analysis. This comprehensive research underscores the potential of 2D materials for innovative applications in nanoelectronics and material science.

Graphene and other two-dimensional (2D) materials exhibit remarkable electronic, thermal, and optical properties that can be tailored by material selection, structural design, and the incorporation of transition metals. This study explores graphite intercalation compounds (GIC) via sonication techniques and extends the approach to alternative carbon allotropes. This work also highlights our advancements on hexagonal boron nitride (hBN), a wide band gap insulator structurally related to graphene, and advancement of intercalation via sonication at ambient temperature.

Additionally, the manipulation of ferromagnetic 2D materials, including chromium (III) iodide and chromium sulfur bromide, is demonstrated through electron beam patterning, highlighting advancements in artificial spin lattices and spin ices.

These works are characterized using PXRD, TEM, and STEM coupled with EDS analysis. This comprehensive research underscores the potential of 2D materials for innovative applications in nanoelectronics and material science.

Bacterial vesicles hold immense potential in various biomedical fields, including vaccines, antimicrobial agents, drug delivery systems, and cancer immunotherapy. Among these, outer membrane vesicles (OMVs) produced by Gram-negative bacteria are among the most extensively studied. While the exact mechanism of OMV production remains unclear, numerous environmental factors have been shown to influence both the yield and composition of OMVs. In this study, we investigated the effect of three different antimicrobial families on OMV production by E. coli. Interestingly, antimicrobials within the same family did not provide the same effects on OMV yield, suggesting that OMV production may not directly correlate with the antimicrobial mechanism of action.

OMVs have demonstrated tumor-inhibitory activity in multiple mouse tumor models. However, their potential toxicity poses a significant challenge, as OMVs have been shown to cause mortality in mice. To address this limitation, we developed bacterial-engineered vesicles (BEVs) as a safer alternative to OMVs. Proteomic analysis revealed that BEVs contained fewer outer membrane proteins compared to OMVs. In vitro assays, BEVs effectively repolarized pro-tumor macrophages (M2) to the anti-tumor phenotype (M1) and promoted dendritic cell maturation. Additionally, BEVs were shown to serve as a versatile platform for antigen peptide display, with the displayed peptides not interfering with BEVs' inherent immunomodulatory activity.

We further evaluated the anti-tumor efficacy of BEVs in a B16F10 melanoma model. The intravenous administration of BEVs significantly inhibited tumor growth and elicited robust immune responses. Flow cytometry analysis of spleen and lymph node samples from BEV-treated mice revealed an elevated M1/M2 macrophage ratio and an increased population of CD8+ T cells. To explore combination therapies, we generated cancer cell-derived vesicles (PD-1 CEVs) using PD-1-transfected B16F10 cells. Interestingly, while BEVs alone inhibited tumor growth effectively, the co-administration of BEVs and PD-1 CEVs resulted in comparable tumor suppression but attenuated immune responses. However, a significant decrease in regulatory T cell percentages was monitored among all vesicle-treated groups compared to the PBS control group. This unexpected immune modulation warrants further investigation to understand the mechanisms underlying PD-1 CEV-mediated immune suppression.

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Bacterial vesicles hold immense potential in various biomedical fields, including vaccines, antimicrobial agents, drug delivery systems, and cancer immunotherapy. Among these, outer membrane vesicles (OMVs) produced by Gram-negative bacteria are among the most extensively studied. While the exact mechanism of OMV production remains unclear, numerous environmental factors have been shown to influence both the yield and composition of OMVs. In this study, we investigated the effect of three different antimicrobial families on OMV production by E. coli. Interestingly, antimicrobials within the same family did not provide the same effects on OMV yield, suggesting that OMV production may not directly correlate with the antimicrobial mechanism of action.

OMVs have demonstrated tumor-inhibitory activity in multiple mouse tumor models. However, their potential toxicity poses a significant challenge, as OMVs have been shown to cause mortality in mice. To address this limitation, we developed bacterial-engineered vesicles (BEVs) as a safer alternative to OMVs. Proteomic analysis revealed that BEVs contained fewer outer membrane proteins compared to OMVs. In vitro assays, BEVs effectively repolarized pro-tumor macrophages (M2) to the anti-tumor phenotype (M1) and promoted dendritic cell maturation. Additionally, BEVs were shown to serve as a versatile platform for antigen peptide display, with the displayed peptides not interfering with BEVs' inherent immunomodulatory activity.

We further evaluated the anti-tumor efficacy of BEVs in a B16F10 melanoma model. The intravenous administration of BEVs significantly inhibited tumor growth and elicited robust immune responses. Flow cytometry analysis of spleen and lymph node samples from BEV-treated mice revealed an elevated M1/M2 macrophage ratio and an increased population of CD8+ T cells. To explore combination therapies, we generated cancer cell-derived vesicles (PD-1 CEVs) using PD-1-transfected B16F10 cells. Interestingly, while BEVs alone inhibited tumor growth effectively, the co-administration of BEVs and PD-1 CEVs resulted in comparable tumor suppression but attenuated immune responses. However, a significant decrease in regulatory T cell percentages was monitored among all vesicle-treated groups compared to the PBS control group. This unexpected immune modulation warrants further investigation to understand the mechanisms underlying PD-1 CEV-mediated immune suppression.

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