Browsing by Subject "Nanoparticle"

Now showing 1 - 13 of 13
  • Thumbnail Image
    Item
    Advanced modeling of nanoparticle nucleation: towards the simulation of particle synthesis
    (2012-11) Liu, Jun
    Nanotechnology holds a lot of promise for the discovery of new phenomena, and many of the envisioned processes involve nanoparticles. These particles are found in chemical sensors, drug targeting and delivery, and one important application is motivated by the need of clean renewable energy sources. Gas-to-particle conversion in the form of homogeneous nucleation within flow systems plays a significant role in a variety of natural and industrial processes of nanoparticle synthesis. In this work, nucleation processes of several metal materials and dibutyl phthalate (DBP) nanoparticles in laminar and turbulent flows are investigated via direct numerical simulations (DNS). The flows consist of condensing vapor diluted in argon or nitrogen issuing into a cooler particle-free stream. DNS facilitates probing the interactive effects of fluid dynamics and nucleation in an accurate manner. The fluid, thermal and chemical fields are obtained by solving the Navier-Stokes, enthalpy, and mass transport equations. Nucleation is simulated via calibrated classical homogeneous nucleation models. Recently developed size dependent surface tension model offers increased accuracy in predicting metal particle nucleation. This approach is attractive in that it promises to be more accurate than the classical nucleation theory while maintaining much of its simplicity when coupling with fluid dynamics. The effects of turbulence on metal nucleation are also studied using fully resolved DNS to elucidate the effects of different stages of fluid mixing on metal particle nucleation. The effects of nucleation on fluid dynamics are investigated via DNS of DBP nucleation within both laminar and turbulent jet flows. The simulations provide a demonstration of how heat release affects the interactions of fluid dynamics and nucleation at different Reynolds numbers and particle formation rates. The results provide insights into the interaction of fluid, thermal transport and nanoparticle nucleation in various flows, which stimulate development of models that will allow engineers to optimize the fluid and thermal environments for industrial nanoparticle production. For brevity, specific conclusions are provided in each chapter.
  • Thumbnail Image
    Item
    Critical considerations in development of mesoporous silica nanoparticles for biological applications.
    (2012-04) Lin, Yu-Shen
    In the past ten years, mesoporous silica nanoparticles have been some of the hottest materials investigated for biomedical use. Mesoporous silica nanoparticles are size-controllable and discrete particles with high surface area, large pore volume, and easy surface modification properties. These unique characteristics make mesoporous silica nanoparticles promising for biological applications. Although there is extensive literature precedent for the synthesis and applications of mesoporous silica nanoparticles, there are several critical issues resulting in limited use of multifunctional mesoporous silica nanoparticles in vitro or in vivo. For example, the large particle size (> 100-nm-diameter) and poor particle stability (aggregation) result in rapid uptake by the reticuloendothelial system, a portion of immune system which removes the nanoparticles from circulation before they reach their tumor target. Another hurdle is the possible unintentional toxicity of such nanoparticles. If the designed mesoporous silica nanoparticles cause unintentional damage to benign cells or healthy tissue and organs, their use will be greatly limited in therapeutic applications. Prior to in vivo animal experiments, unintentional cytotoxicity must be minimized and well studied. Based on the critical considerations described above, an ideal mesoporous therapeutic should possess the following characteristics prior to in vivo studies: (1) small size (<50 nm); (2) high surface area; (3) high stability; and (4) minimal unintentional cytotoxicity. Chapter One reviews the development and use of mesoporous silica nanoparticles for biomedical use. Various components have been incorporated into mesoporus silica nanoparticles to yield various functionalities, like controlled drug release, targeting, and multimodal imaging for diagnosis. With more and more complex designs for mesoporous silica nanoparticles, practical considerations for in vivo use must be taken into account. Chapter Two describes our novel method to synthesize highly stable, redispersible, and small mesoporous silica nanotherapeutics. This chapter discusses the particle stability of bare and modified mesoporous silica in various biological media. Critical synthetic parameters including introduction of hydrophilic and hydrophobic organosilanes and hydrothermal treatment are key to synthesize ultrastable and redispersible mesoporous silica nanoparticles. Chapter Three examines the cytotoxicity of mesoporous silica nanoparticles to human RBCs, mouse mast cells, and human endothelial cells using (1) a hemolysis assay, (2) an electrochemical assay of cell function and (3) a microfluidic device. The experimental results reveal that mesoporous silica nanoparticles have lower adverse effects on RBCs and mast cells than their similarly sized nonporous counterparts. In addition, shear stress effects on the cytotoxicity of unmodified mesoporous silica will be discussed. In Chapter Four, a novel one-pot synthesis route was developed to fabricate size-tunable multifunctional mesoporous silica nanoparticles. Based on the experience from improving bare mesoporous silica stability, the hydrothermally assisted organosilane modification method was applied to improve the particle stability, T2 relaxivity stability, and acid resistance of magnetic mesoporous silica nanoparticles. In the last part of my research work, Chapter Five investigates cytotoxicity of new carbon nanomaterials, graphene oxide and graphene in human erythrocytes and skin fibroblasts. The cytotoxicity results show that the physico-chemical properties, including the particle size, exfoliation extent, oxygen content, and aggregation state of graphene oxide and graphene greatly influence their cytotoxicity. This collaborative work also inspired me to consider a possible future direction involving the incorporation of graphene oxide or graphene into mesoporous silica nanoparticles to control drug release via a heat-driven route. To conclude, Chapter Six reviews my thesis work and highlights the advances I have made in the fields of nanomedicine and nanotoxicity. In addition, possible future directions are also described.
  • Thumbnail Image
    Item
    Effects of nanocrystalline silicon inclusions in doped and undoped thin films of hydrogenated amorphous silicon.
    (2009-12) Blackwell, Charlie Pearman
    Hydrogenated amorphous silicon has attracted considerable interest as a low-cost material for various large-area electronic devices, such as scanners, thin film transistors employed in flat panel displays, and photovoltaic devices. A major limitation of amorphous silicon is a light-induced degradation of the photoconductivity and dark conductivity, associated with the creation of metastable dangling bond defects. Recent reports that mixed phase thin films, consisting of silicon nanocrystallites embedded within a hydrogenated amorphous silicon matrix, display a resistance to this light-induced degradation have motivated the development of a novel deposition system to synthesize such materials. Conventional techniques to generate such amorphous/nanocrystalline mixed phase films involve running a Plasma Enhanced Chemical Vapor Deposition system very far from those conditions that yield high quality amorphous silicon. A dual-plasma co-deposition system has thus been constructed, whereby the silicon nanoparticles can be fabricated in one chamber, and then injected into a second plasma reactor, in which the surrounding amorphous silicon is deposited. The deposition process, as well as structural, optical, and electronic characterization of these films, including the dark conductivity, photoconductivity, infra-red absorption spectra, micro-RAMAN spectra, and the optical absorption spectra, will be discussed for these films.
  • Thumbnail Image
    Item
    Formulation and delivery of polymeric nanoparticle-assisted vaccine against melanoma
    (2015-04) Niu, Lin
    Poly (lactide-co-glycolide) (PLGA) nanoparticle (NP) is a widely used biodegradable carrier for drug and vaccine delivery. This thesis focused on the formulation, delivery and efficacy of PLGA NP for its potential application in melanoma immunotherapy. To enable reliable PLGA NP formulation for clinical use such as vaccination, lyophilization is the method of choice to manufacture dry NP dosage form. A major risk of the lyophilization product development for NPs is the irreversible NP aggregation due to freezing and drying stress. Based on real-time imaging, freezing stress could be attributed to freeze-concentration of NPs. Cryo-scanning electron microscopy (cryo-SEM) revealed individual NP separately embedded in the freeze-concentrate interstitial space of the sucrose formulation, leading to corroborative support for the "particle isolation" hypothesis of cryo-protection. Various sphere packing models were investigated to guide the rational design of cryo-/lyo-protectant containing NP formulations. To facilitate precise intradermal delivery of NP formulation for vaccination, microneedle array-mediated administration was utilized to deliver large volume of NPs into the skin. The majority of the infused PLGA NPs were retained locally. A PLGA NP vaccine formulation delivered intradermally elicited robust humoral and cellular immunity. Antigen-loaded NP formulation triggered quicker and stronger high affinity antibody responses compared to the soluble antigen formulation. Vemurafenib, a selective inhibitor of BRAF V600E, induces apoptotic melanoma cell death and remarkable tumor burden reduction. However, drug resistance invariably occurs. Novel TLR7/8 agonists were encapsulated in PLGA particulate formulation as immunostimulatory nanoparticles (ISNP) to boost immune response against drug-resistant melanoma. NP-mediated intracellular delivery contributed to enhanced dendritic cell activation in vitro and antigen-specific CD8+ T cell proliferation in vivo. The prophylactic vaccination using NP-assisted whole tumor cell formulation prolonged the survival of mice challenged with melanoma. To take advantage of the clearance of melanoma antigens by immune system in the context of BRAF inhibition, an ISNP-assisted in situ whole tumor cell vaccination strategy was investigated using BRAF V600E positive mouse SM1 melanoma cells. Despite the suppressed tumor growth, no survival benefit was observed in this therapeutic vaccination model.
  • Thumbnail Image
    Item
    Functionalization of Magnetic Nanoparticles with Deoxynucleotide Triphosphates for Utilization in DNA Sequencing
    (2023-02) Nazareth, Calvin
    Current methods for DNA sequencing leave a lot to be desired. There is immense research focused on developing methods to sequence longer and larger samples of DNA and to do so more rapidly. One possible new approach to DNA sequencing uses magnetically labeled deoxynucleotide triphosphates (dNTPs) as the complimentary bases for a sequencing-by-synthesis approach. The polymerase in this system would be immobilized on a sensor so that when the nucleotide is attached to the growing strand, the sensor can detect the signal. As the polymerase completes the strand for DNA extension, the signal from each magnetic nanoparticle (MNP) is recognized and generates a sequence.The contents of this thesis provide results for two critical initial steps in developing the proposed method. Firstly, we attached dNTPs to magnetic nanoparticles to create dNTP-MNP conjugates. We attempted two methods of conjugation with numerous characterization techniques to confirm the attachment. Secondly, we studied how the dNTP-MNP conjugation affected the dNTPs in quantitative polymerase chain reaction (qPCR) to model how they would interact with a polymerase in a hypothetical sequencer. The characterization results confirmed the conjugation of the dNTP to the MNP. qPCR was performed with various conditions and solvents which led to the conclusion that the MNP conjugation does not hinder polymerase interaction with the dNTP. This is a crucial result for the development of such a sequencer by providing the groundwork for the continuation of the project.
  • Thumbnail Image
    Item
    Glycopolymers for Targeted Gene Delivery and Genome Editing
    (2017-08) Dhande, Yogesh
    Targeted delivery of therapeutics is of great interest to reduce toxicity and immunogenicity of the treatment. In particular, the liver is an ideal target for nucleic acid therapeutics due to its large size, regenerative capacity, and the role in producing serum proteins. In this work, N-acetyl-D-galactosamine (GalNAc) ligands clustered into a polymeric architecture were studied for enhanced binding to the asialoglycoprotein receptors (ASGPRs) on hepatocytes. A series of cationic glycopolymers based on this architecture was used to encapsulate plasmids (pDNA) into polymer-pDNA complexes (polyplexes) and deliver them to receptor-specific cells. The GalNAc-derived polyplexes were colloidally stable and showed cell type-specific gene expression in cultured cells. This work demonstrated the versatility of glycopolymers in selective delivery of therapeutics to cells of interest. We sought to further understand the role of such gene-delivery vehicles in genome editing applications using the CRISPR/Cas9 system. Our results show that the gene delivery vehicle can play a role in promoting homology-directed repair over nonhomologous end joining based on its gene delivery properties. The frequency of editing correlates with the fraction of cells expressing Cas9 above a certain threshold and higher expression does not contribute to any gains in editing efficiency. Taken together, these observations suggest that future gene-delivery vehicles aimed for genome editing applications should be designed to deliver only a sufficient amount of DNA but to a large fraction of cells.
  • Thumbnail Image
    Item
    Laser Induced Gold Nanoparticle Heating: Thermal Contrast in Lateral Flow Immunoassays
    (2014-06) Qin, Zhenpeng
    Nanomaterial research has grown exponentially for biomedical applications in imaging, diagnostics and therapeutics. Within these areas laser nanoparticle heating uniquely enables important applications including molecular delivery or destruction, endosomal release of genes or siRNA, and selective cell or tumor destruction, with nano to macro-scale spatiotemporal control and precision. While our studies were initially motivated to support in vitro and in vivo biomedical applications, further study of laser nanoparticle heat transfer at a fundamental level, suggested a further opportunity for use in point-of-care diagnostics, in particular for gold nanoparticle (GNP) based lateral flow assays. The lateral flow immunoassay (LFA) is a point-of-care diagnostic test that has found broad applications in medicine, agriculture, and over-the-counter personal use such as for pregnancy testing. Within the LFA, antibody-coated GNPs are used as reporters due to accumulation (i.e. antigen-antibody recognition) on a test line that leads to a visually detectable signal due to a deep red color indicative of GNP accumulation. However, one universally recognized limitation of LFA is the low sensitivity of this visual readout. In this work, we developed a low cost solution to this sensitivity using laser GNP heating. Specifically, metallic nanoparticles generate heat upon optical (i.e. laser) stimulation. This in turn can be used to enhance detection of GNPs, creating a thermal contrast amplification (TCA). We have shown that TCA improves the analytical sensitivity on several existing, commercial LFAs. For instance, our results show a 32-fold improvement in analytical sensitivity using an FDA-approved cryptococcal antigen LFA. My dissertation then describes the development of TCA devices and components that will ultimately allow clinical, laboratory and eventually lay people alike to use and benefit from the technology. In particular, a benchtop TCA prototype device is described and engineering efforts continue to place TCA in a number of clinical laboratories and eventually create a product for infectious disease detection. The absorption and heat generation from nanoparticles eventually determine the magnitude of TCA. Thus, the use of higher heat generating nanoparticles can further improve the LFA sensitivity. Literature suggests that nanoparticle morphology plays an important role in the optical absorption, and nanorods absorb more light energy than nanospheres with the same amount of gold per particle based on previous calculations. Our study suggests that the optical absorption and extinction of gold nanorods are significantly reduced (more than 70%) by polydispersity (i.e. distribution of size and shape) while relatively unaffected for gold nanospheres (less than 10% change). This indicates that the expected enhancement due to absorption of gold nanorods over nanospheres may be greatly diminished by the presence of polydispersity in real nanoparticle samples. Further work incorporating higher heating gold nanoparticles (i.e. larger gold spheres and well characterized gold nanorods) to improve existing lateral flow assays such as to one day rival the sensitivity of more costly, time and labor intesive laboratory testing is underway. In summary, this dissertation describes the foundation of a new technology entitled: Thermal Contrast Amplication (TCA). TCA has been patented and licensed by a start up that is pursuing commercialization and broader societal impact of the technology. Future work including the development of a handheld TCA device for point-of-care diagnostics, and a next generation LFA optimized for TCA are underway. TCA and LFA together represent a potential disruptive platform technology that can improve early diagnosis of infectious diseases and general biomolecular screening in areas of medicine, agriculture, and biodefense where a quick and sensitive detection is needed.
  • Thumbnail Image
    Item
    Nanostructures, Nanoparticles, and 2D Materials from Nonthermal Plasmas
    (2021-02) Beaudette, Chad
    The bottom-up synthesis of thin films, nanostructures, and nanoparticles from nonthermal plasmas has been limited largely to both gas-phase and highly-volatile carbon precursors. This has stymied the application of nonthermal plasmas to several new types of materials as there are often no gas-phase or highly volatile precursors that exist for their synthesis. The sublimation of solid and low volatility liquid precursors are used here to expand the realm of new materials towards sulfide Van der Waals 2D materials, high surface area nitride nanostructured plasmonic materials, nitrogen-doped oxide nanoparticles, and crystalline metal aluminum nanoparticles. Plasmonic photodetectors and photocatalytic nanoparticles are demonstrated herein to show the utility of some of the as produced materials. Moreover, traditional nanoparticle reactor limitations such as metallic film deposition between the exciting electrode and the plasma are discussed and new reactors are developed to overcome such limitations. In addition, parameters such as the location of the powered electrode and the location of the gas inlets relative to one another are critical to the production of better materials and examples will be demonstrated herein.
  • Thumbnail Image
    Item
    Nonthermal Plasma Synthesis Of Nanoparticles And Double Probe Diagnostic
    (2023-04) Xiong, Zichang
    Nanoparticles are tiny particles that range in size from 1 to 100 nanometers. Their large surface area-to-volume ratio allows them to interact with their surroundings in unique ways. Nonthermal plasmas are particularly attractive sources for nanoparticle synthesis. In these plasmas, energetic plasma electrons decompose molecular gaseous precursors, producing radicals, which lead to the nucleation and growth of nanoparticles. This thesis investigates the feasibility of double probe measured in nonthermal dusty plasma and the mechanism of particle trapping and heating in nonthermal plasma synthesis of nanoparticles. This thesis also studies ICP synthesized size-tunable y-Al2O3 nanocrystals and reducing iron oxide particles by a MW hydrogen plasma. Double probes are utilized to diagnose the plasma properties of an argon:silane plasma containing nanoparticles. We demonstrate good stability of current-voltage characteristics over several minutes of operation. In addition, we developed a zero-dimensional global model to investigate the effect of the presence of nanoparticles on the plasma properties. Critical processes were investigated in nonthermal plasma synthesis of nanoparticles. We present experimental and computational evidence that, during their growth in the plasma, sub-10 nm silicon particles become temporarily confined in an electrostatic trap in radio-frequency excited plasmas until they grow to a size at which the increasing drag force imparted by the flowing gas entrains the particles, carrying them out of the trap. Furthermore, a nanoparticle heating model was used to study the temperature increase of a particle exposed to a plasma by exothermic surface reactions. y-Al2O3 is widely used as a catalyst and catalytic support due to its high specific surface area and porosity. We report a single-step synthesis of size-controlled and monodisperse, facetted y-Al2O3 nanocrystals in an inductively coupled nonthermal plasma reactor using trimethylaluminum and oxygen as precursors. Nanocrystal size tuning was achieved by varying the total reactor pressure yielding particles as small 3.5 nm, below the predicted thermodynamic stability limit for y-Al2O3. CO2 emissions from the steel production account for 8% of the global anthropogenic CO2 emissions and are a key challenge towards achieving a carbon-neutral future. We report an electrified process for reducing iron ore particles using atmospheric pressure hydrogen plasma powered by microwave energy. Iron ore particles were reduced steadily on a mesh exposed to the plasma. Moreover, in-flight iron ore reduction was achieved using the atmospheric pressure hydrogen microwave plasma, which is more than 100 times faster than the previously reported flash in-flight iron ore reduction by a thermal hydrogen technique.
  • Thumbnail Image
    Item
    Synthesis, characterization, and applications of porous and hierarchically-porous silica nanostructures
    (2014-10) Swindlehurst, Garrett Richard
    Silicate nanostructures can be broadly defined as any material primarily composed of silicon dioxide and having one or more dimensions smaller than 100 nm. Silica is formed of SiO4 tetrahedra connected at their vertices, and the way in which these tetrahedra can be arranged leads to materials classified as amorphous or crystalline, depending on the degree of long-range order in the structure. Due to the complexity of tetrahedral connectivity that is possible, pores can be formed in silicas with length scales ranging from a few angstroms to tens of nanometers. Some microporous silicates exist in nature, but many other porous silicas of considerable importance to chemical engineering are synthetic. One important class of these synthetic porous silicates is the zeolites, which contain pores on the size of angstroms and therefore can act as molecular sieves. In this dissertation, methods for the synthesis and characterization of "zero-dimensional" silica nanoparticles, "two-dimensional" zeolite nanosheets, and "three-dimensional" mesoporous silicas and zeolites are presented. Applications for these materials in catalytic and adsorption processes are also explored. Many of these nanostructured silicates contain hierarchical pore structure with different characteristic pore sizes existing in the materials. One particularly studied material, the self-pillared pentasil (SPP) zeolite, contains both the microporosity of traditional zeolites and mesoporosity resulting from its crystal growth mechanism. Hierarchical pore networks can significantly improve intraparticle mass transfer for interacting chemical species, offering great performance gain in the considered applications.
  • Thumbnail Image
    Item
    Synthesis, characterization, and applications of porous and hierarchically-porous silica nanostructures
    (2014-10) Swindlehurst, Garrett Richard
    Silicate nanostructures can be broadly defined as any material primarily composed of silicon dioxide and having one or more dimensions smaller than 100 nm. Silica is formed of SiO4 tetrahedra connected at their vertices, and the way in which these tetrahedra can be arranged leads to materials classified as amorphous or crystalline, depending on the degree of long-range order in the structure. Due to the complexity of tetrahedral connectivity that is possible, pores can be formed in silicas with length scales ranging from a few angstroms to tens of nanometers. Some microporous silicates exist in nature, but many other porous silicas of considerable importance to chemical engineering are synthetic. One important class of these synthetic porous silicates is the zeolites, which contain pores on the size of angstroms and therefore can act as molecular sieves. In this dissertation, methods for the synthesis and characterization of "zero-dimensional" silica nanoparticles, "two-dimensional" zeolite nanosheets, and "three-dimensional" mesoporous silicas and zeolites are presented. Applications for these materials in catalytic and adsorption processes are also explored. Many of these nanostructured silicates contain hierarchical pore structure with different characteristic pore sizes existing in the materials. One particularly studied material, the self-pillared pentasil (SPP) zeolite, contains both the microporosity of traditional zeolites and mesoporosity resulting from its crystal growth mechanism. Hierarchical pore networks can significantly improve intraparticle mass transfer for interacting chemical species, offering great performance gain in the considered applications.
  • Thumbnail Image
    Item
    Three-dimensional dosimetry around small distributed high-Z materials
    (2016-05) Warmington, Leighton
    Patients are increasingly undergoing radiotherapy procedures, in which small metals are implanted in the body for target localization for IGRT or targeted therapies. Previous, interface dosimetry studies focused high-Z materials irradiated by low energy beams where the dose enhancement is large. In the majority of the cases, they used one or two dimensional detectors. Therapeutic beams, however, are mostly 6 MV and higher with significantly less dose enhancement. Over the last decade, significant improvements in polymer gel dosimetry have been made allowing for improved 3D dose measurements. The purpose of this study was to better understand the dose around distributed high-Z materials irradiated by high energy photon beams and investigate the feasibility of 3D dose measurements. A Monte Carlo code was used to determine the effect of various foil configurations. The dosimetric effect of foil thickness, separation, energy and other factors were investigated. Software tools were also developed to process the data. These results were used to help identify suitable experimental setups. The dose around two foils was compared to the dose resulting from adding the dose of two single foils. The dose around a single foil was also compared to the dose around a fiduciary marker. Later on, we looked at how distributing the thickness of the high-Z foil over a wider area affected dose and how that compared to a to the dose around a single foil. Finally, we looked at the effect of pair production and how it affected the distribution of dose in select configurations. Several polymer gel dosimeter (PGD) were evaluated and two were selected for further study. Various formulations were investigated and procedures developed to meet the needs of the project. Materials compatibility studies were performed to ensure that there were no reactions between the PGD and inserted materials within the time frame of the studies. PGDs were manufactured and thin lead foils with the configuration determined earlier were inserted into the polymer gel. The PGDs was irradiated with 18 MV photons and the dose was quantified using MRI with a multiple spin echo technique for the measurement of the spin-spin relaxation rate (R2). The measured dose data were compared to theoretical data obtained from Monte Carlo experiments. The dose profiles around the foils from the PGD were in agreement with dose values from simulation. This project demonstrated that it is feasible to use polymer gel dosimetry to measure the fine dosimetric structures around a small metallic object. We also determined that material, foil thickness, separation and photon energy had the largest effect on the dose in-between a two foil configuration. When the foils were close, we found that the dose around the two foils was larger but not significantly different from the combined dose of two single foils with the same separation. We also found that the dose upstream and downstream of a distributed foil is less that the upstream and downstream dose around a single foil of equivalent thickness.
  • Thumbnail Image
    Item
    Zinc oxide nanoparticles: doping, Inkjet printing, and electron accepting from photoexcited porphyrin dyes
    (2013-06) Bierbaum, Andrew Joseph
    This research attempted to extend the useful applications of ZnO by investigating ZnO nanoparticles, doping ZnO nanoparticles, characterizing electron injection from dye molecules into ZnO nanoparticles, and depositing thin films of doped ZnO nanoparticles using inkjet printing. Chapter 1 describes research that produced particles ranging from 2.7 nm to 1 μm of undoped and doped ZnO. These particles were made using solution methods with zinc acetate and aluminum and gallium nitrate salts as dopants, and the particles were characterized by ultraviolet visible absorption, photoluminescence, infrared absorption, and transmission or scanning electron microscopy. The doped ZnO nanoparticles displayed optical signatures of doping in particles larger than 10 nm. This is significant because doping of nanoparticles is still not fully understood, and there are few examples of successfully doping nanoparticles. Chapter 2 describes the research done toward inkjet printing of ZnO films for potential use in a fully inkjet printed solar cell. The research aim was to produce a TCO film of ZnO using inkjet printing that had a bulk resistivity between 10-2 and10-3 Ω cm, a thickness between 0.1 and 1 μm, the highest transparency possible, and processed using conditions under 250 ºC. Film produced using solution methods including inkjet printing were characterized by four point probe ohmmeter, x-ray diffraction, ultraviolet visible absorption, visible microscopy, profilometry, and scanning electron microscopy. Inkjet printed films produced using nanoparticles did not meet the production requirements, but ii progress towards these goals are presented along with the successes and shortcoming of the methods used. Chapter 3 describes the research done on charge transfer from photoexcited porphyrin dyes into ZnO nanoparticles dispersions in methanol. The goal of this research was to further the understanding of the dye-semiconductor interaction and important electron transfer characteristics. Using a series of three porphyrin dyes and a range of particle sizes, the rate of electron transfer was investigated.