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Phototoxic Effects of Titanium Dioxide Nanoparticles on Daphnia Magna
Titanium dioxide nanoparticles (TiO2-NP) are one of the most abundantly utilized nanomaterials in the world. Studies have demonstrated the mechanism of acute toxicity in TiO2-NP to be the production of reactive oxygen species (ROS) leading to oxidative stress and mortality in exposed organisms. It has also been demonstrated that the anatase crystalline conformation is capable of catalyzing the cleavage of water molecules to further increase the concentration of ROS in the presence of ultraviolet radiation. This photoenhanced toxicity significantly lowers the toxicity threshold of TiO2-NP to environmentally relevant concentrations (ppb). The goal of this study was to determine whether dietary uptake and accumulation of TiO2-NP in the aquatic filter feeder Daphnia magna resulted in photoenhanced toxicity. D. magna and S. caprincornatum were exposed to aqueous solutions of 20ppm and 200ppm TiO2-NP for 24hrs and then transferred to clean moderately hard water. Samples were taken at various time points, dried, and TiO2 quantified using ICP-MS. Toxicity assays were run on D. magna using three TiO2-NP (20ppm, 200ppm) exposure protocols and two ultraviolet radiation treatments. The first exposure group was exposed to aqueous solutions of TiO2-NP for the duration of the test. The second exposure group was exposed to TiO2-NP for an hour and then transferred to clean water. The third exposure group was fed S. capricornatum that had been allowed to adsorb TiO2-NP. All samples were then placed in an outdoor UV exposure system and exposed to either full spectrum sunlight (with UV) or filtered sunlight (no UV). Here we show that TiO2 uptake peaked at one hour of exposure likely due to sedimentation of the particles out of suspension, thus decreasing bioavailability for the duration of the test. Interetsingly, when D. magna were moved to clean water, aqueous concentrations of TiO2 increase as a result of depuration from the gut …
Targeted and Metal-loaded Polymeric Nanoparticles As Potential Cancer Therapeutics
Polymeric nanoparticles were designed, synthesized, and loaded with metal ions to explore the therapeutic potential for transition metals other than platinum found in cisplatin. Nanoparticles were synthesized to show the potential for polymer based vectors. Metal loading and release were characterized via Inductively Coupled Plasma Mass Spectrometry (ICP MS), Energy Dispersive X-Ray Spectroscopy (EDX), X-Ray Photoelectron Spectroscopy (XPS), and Elemental Analysis. Targeting was attempted with the expectation of observed increased particle uptake by cancer cells with flow cytometry and fluorescence microscopy. Results demonstrated that a variety of metals could be loaded to the nano-sized carriers in an aqueous environment, and that the release was pH-dependent. Expected increased targeting was inconsistent. The toxicity of these particles was measured in cancer cells where significant toxicity was observed in vitro via dosing of high copper-loaded nanoparticles and slight toxicity was observed in ruthenium-loaded nanoparticles. No significant toxicity was observed in cells dosed with metal-free nanoparticles. Future research will focus on ruthenium loaded polymeric nanoparticles with different targeting ligands dosed to different cell lines for the aim of increased uptake and decreased cancer cell viability.
Cooperative bi-exponential decay of dye emission coupled via plasmons
This article demonstrates that the relaxation in the sub-radiant system leads to the population of the sub-radiant states by dephasing the super-radiant Dicke states giving rise to the bi-exponential decay in agreement with the experiments.
New mechanism of plasmons specific for spin-polarized nanoparticles
This article experimentally shows that Co nanoparticles with a single-domain crystal structure support a plasmon resonance at approximately 280 nm with better quality than gold nanoparticle resonance in the visible. The magnetic nature of these nanoparticles suggests a new type of these plasmons.
Applications of Metallic Clusters and Nanoparticles via Soft Landing Ion Mobility, from Reduced to Ambient Pressures
Nanoparticles, simple yet groundbreaking objects have led to the discovery of invaluable information due to their physiological, chemical, and physical properties, have become a hot topic in various fields of study including but not limited to chemistry, biology, and physics. In the work presented here, demonstrations of various applications of chemical free nanoparticles are explored, from the determination of a non-invasive method for the study of the exposome via using soft-landing ion mobility (SLIM) deposited nanoparticles as a matrix-assisted laser desorption/ionization (MALDI-MS) matrix replacement, to the direct SLIM-exposure of nanoparticles onto living organisms. While there is plenty of published work in soft-landing at operating pressures of 1 Torr, the work presented here shows how this technology can be operated at the less common ambient pressure. The ease of construction of this instrument allows for various modifications to be performed for a wide array of applications, furthermore the flexibility in metallic sample, operating pressure, and deposition time only open doors to many other future applications. The work presented will also show that our ambient SLIM system is also able to be operated for toxicological studies, as the operation at ambient pressure opens the door to new applications where vacuum conditions are not desired.
Nonlinear and Quantum Optics Near Nanoparticles
We study the behavior of electric fields in and around dielectric and metal nanoparticles, and prepare the ground for their applications to a variety of systems viz. photovoltaics, imaging and detection techniques, and molecular spectroscopy. We exploit the property of nanoparticles being able to focus the radiation field into small regions and study some of the interesting nonlinear, and quantum coherence and interference phenomena near them. The traditional approach to study the nonlinear light-matter interactions involves the use of the slowly varying amplitude approximation (SVAA) as it simplifies the theoretical analysis. However, SVVA cannot be used for systems which are of the order of the wavelength of the light. We use the exact solutions of the Maxwell's equations to obtain the fields created due to metal and dielectric nanoparticles, and study nonlinear and quantum optical phenomena near these nanoparticles. We begin with the theoretical description of the electromagnetic fields created due to the nonlinear wavemixing process, namely, second-order nonlinearity in an nonlinear sphere. The phase-matching condition has been revisited in such particles and we found that it is not satisfied in the sphere. We have suggested a way to obtain optimal conditions for any type and size of material medium. We have also studied the modifications of the electromagnetic fields in a collection of nanoparticles due to strong near field nonlinear interactions using the generalized Mie theory for the case of many particles applicable in photovoltaics (PV). We also consider quantum coherence phenomena such as modification of dark states, stimulated Raman adiabatic passage (STIRAP), optical pumping in $4$-level atoms near nanoparticles by using rotating wave approximation to describe the Hamiltonian of the atomic system. We also considered the behavior of atomic and the averaged atomic polarization in $7$-level atoms near nanoparticles. This could be used as a prototype to study …
Hydrogen Adsorption on Platinum-Gold Bimetallic Nanoparticles: A Density Functional Theory Study
Article on hydrogen adsorption on platinum-gold bimetallic nanoparticles.
Electrostatic enhancement of light emitted by semiconductor quantum well
This article proposes an electrostatic mechanism for enhancement of light radiated from semiconductor emitter which is comparable in effect to plasmonic mechanism.
Synthesis of Nickel and Nickel Hydroxide Nanopowders by Simplified Chemical Reduction
This article presents a simple, inexpensive, and efficient chemical method of synthesizing nickel and nickel hydroxide powders with nanometer-sized particles.
Development of Biodegradable Nanocarriers Loaded with a Monoclonal Antibody
This article examines the feasibility of encapsulating monoclonal antibodies within poly(lactic-co-glycolic acid) (PLGA) nanoparticles using a water/oil/water double emulsion solvent evaporation technique. This method can be used to prepare protective polymeric nanoparticles for transporting functional antibodies to the cytoplasmic compartment of cancer cells. The author's studies achieved successful formulation of antibody loaded polymeric nanoparticles, thus indicating that a PLGA-based antibody nanoformulation is a promising intracellular delivery vehicle for a large number of new intracellular antibody targets in cancer cells.
International Journal of Lightweight Materials and Manufacture
This article employs a recently introduced magnesium-samarium oxide (Mg–Sm₂O₃) nanocomposite, with different volume fractions of nanosize Sm₂O₃ particles as reinforcement, to study ambient temperature rate-dependent plastic response of the material.
Shining Light on Chitosan: A Review on the Usage of Chitosan for Photonics and Nanomaterials Research
This article highlights the different molecular-nano systems that are prepared or stabilized using the Chitosan polymer.
Plasmonically-powered hot carrier induced modulation of light emission in a two-dimensional GaAs semiconductor quantum well
Article describes an experiment in which a hot-electron-enabled route to controlling light with dissipative loss compensation in semiconductor quantum light emitters has been realized for tunable quantum optoelectronic devices via a two-species plasmon system.
Potential Toxicity and Underlying Mechanisms Associated with Pulmonary Exposure to Iron Oxide Nanoparticles: Conflicting Literature and Unclear Risk
This review article will focus on known risks following iron oxide nanoparticles (IONPs) exposure supported by human, animal, and cell culture-based studies, the potential challenges intrinsic to IONPs toxicity assessment, and how these may contribute to the poorly characterized IONPs toxicity profile.
Growth of Highly-Ordered Metal Nanoparticle Arrays in the Dimpled Pores of an Anodic Aluminum Oxide Template
Article presents a reliable, scalable, and inexpensive technology for the fabrication of ordered arrays of metal nanoparticles with large areal coverage on various substrates. Using a simple model, the experimental results were interpreted and supported by numerical estimations.
The Potential Role of Nanotechnology in Therapeutic Approaches for Triple Negative Breast Cancer
This review is focused on opportunities for developing new approaches for filling the current void in an effective treatment for Triple Negative Breast Cancer, TNBC, patients. Triple Negative Breast Cancer, TNBC, a highly aggressive and metastatic type of breast cancer, is characterized by loss of expression of the estrogen receptor (ER), progesterone receptor (PR), and a lack of overexpression of the human epidermal growth factor receptor 2 (HER2).
Novel thin polymeric magnetic membranes study for applications in the future biomedical devices
Article describes how biomedical devices such as pumping/mixing fluids, cell-culturing, and drug delivery often use different actuation methods. In regard to magnetic actuation, membranes with a local distribution of magnetic particles are investigated and compared to membranes with randomly distributed magnetic particles, which in turn may enhance the actuation performance for certain applications.
Growth Mechanisms of Nano-to Micro-Sized Lead Sulfate Particles
This article aims to determine the nucleation and growth mechanisms of PbSO4 nanoparticles in various solutions to potentially reduce or control the buildup of PbSO4 on battery electrodes over time.
Electrodeposition of Cu-Ni Composite Coatings
This book chapter reviews the electrodeposition of Cu-Ni incorporated with nano- to microparticles to produce metal matrix composites.
Radio-Frequency Actuated Polymer-Based Phononic Meta-Materials for Control of Ultrasonic Waves
This article describes the achievement of radio-frequency control of a n ultrasonic phononic crystal by encapsulating it in a composite of high k-10% KF-doped BaTiO₃ dielectric nanoparticles with poly(N-isopropylacrylamide) (PNIP Am)-based hydrogel.
Synthesis, Uses and Compositions of Crystal Hydrogels
Patent relating to the synthesis, uses and compositions of crystal hydrogels.
Escherichia Coli CSRB Gene and RNA Encoded Thereby
Patent regarding the synthesis, uses and compositions of crystal hydrogels.
Single-Step Photochemical Formation of Near-Infrared-Absorbing Gold Nanomosaic within PNIPAm Microgels: Candidates for Photothermal Drug Delivery
Article demonstrating the dynamic potential for tailoring the surface plasmon resonance (SPR), size, and shapes of gold nanoparticles (AuNPs) starting from an Au(I) precursor, chloro(dimethyl sulfide)gold (I) (Au(Me2S)Cl), in lieu of the conventional Au(III) precursor hydrogen tetrachloroaurate (III) hydrate (HAuCl4). This approach presents a one-step method that permits regulation of an Au(I) precursor to form either visible-absorbing gold nanospheres or near-infrared-window (NIRW)-absorbing anisotropic AuNPs.
Metallic Nanodroplet Induced Coulomb Catalysis for Off-Resonant Plasmonic Enhancement of Photoemission in Semiconductors
This article reports a new mechanism based on electrostatic interactions of carriers and their image charges in metals to generate more photons from optical sources at frequencies that are off-resonant to the localized plasmon frequency.
Nanoparticle-assisted microwave absorption by single-wall carbon nanotubes
This article discusses nanoparticle-assisted microwave absorption by single-wall carbon nanotubes.
Biocompatible Hybrid Nanomaterials Involving Polymers and Hydrogels Interfaced with Phosphorescent Complexes and Toxin-Free Metallic Nanoparticles for Biomedical Applications
The major topics discussed are all relevant to interfacing brightly phosphorescent and non-luminescent coinage metal complexes of [Ag(I) and Au(I)] with biopolymers and thermoresponsive gels for making hybrid nanomaterials with an explanation on syntheses, characterization and their significance in biomedical fields. Experimental results and ongoing work on determining outreaching consequences of these hybrid nanomaterials for various biomedical applications like cancer therapy, bio-imaging and antibacterial abilities are described. In vitro and in vivo studies have been performed on majority of the discussed hybrid nanomaterials and determined that the cytotoxicity or antibacterial activity are comparatively superior when compared to analogues in literature. Consequential differences are noticed in photoluminescence enhancement from hybrid phosphorescent hydrogels, phosphorescent complex ability to physically crosslink, Au(I) sulfides tendency to form NIR (near-infrared) absorbing AuNPs compared to any similar work in literature. Syntheses of these hybrid nanomaterials has been thoroughly investigated and it is determined that either metallic nanoparticles syntheses or syntheses of phosphorescent hydrogels can be carried in single step without involving any hazardous reducing agents or crosslinkers or stabilizers that are commonly employed during multiple step syntheses protocols for syntheses of similar materials in literature. These astounding results that have been discovered within studies of hybrid nanomaterials are an asset to applications ranging from materials development to health science and will have striking effect on environmental and green chemistry approaches.
Synthesis and Characterization of Copper Releasing Polymer Nanoparticles
Polymeric nanoparticles were synthesized and loaded with Cu²⁺ to explore the therapeutic potential for catically active transition metal ions and complexes other than cisplatin. Two types of nanoparticles were synthesized to show the potential for polymer based vectors. Copper loading and release were characterized via inductively coupled plasma mass spectrometry (ICP MS), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and elemental analysis. Results demonstrated that Cu could be loaded to the nano-sized carriers in an aqueous environment, and that the release was pH-dependent. The toxicity of these particles was measured in HeLa cells where significant toxicity was observed in vitro via dosing of high Cu-loaded nanoparticles. No significant toxicity was observed in cells dosed with Cu-free nanoparticles.
Nanoparticles & Cancer Cells
Undergraduate research thesis studying nanoparticles as a therapeutic approach in cancer-targeting drugs and their effects on mammals. The author hypothesizes that nanoparticles can make cancer-targeting drugs more effective. This thesis also includes the PowerPoint slides presented at UNT Scholar's Day.
Metallic nanoparticle production and exposure/deposition system for toxicological research applications using zebrafish
Article presents a method that provides a novel way to synthesize NPs and expose biological organisms for various toxicological analysis.
[Examining the Role of Nanomaterials and Optical Sensors for Genomics Research]
This presentation introduces the possibility of using nanomaterials and optically active sensors in genomics research. The presenter shares the history and applications of nanomaterials, introduces their research into optical-luminescent sensors and optically active plasmonic nanoparticles, and explores how they might be used in genomics. It was presented at the UNT Transdisciplinary Conference on Ancestral Genomics Research which was held virtually on November 20-21, 2020.
Novel Metal-Containing Nanoparticle Composites for Cancer Therapy and Imaging
With all the improvements in cancer treatments, multidrug resistance is still the major challenge in treating cancer. Cells can develop multidrug resistance (MDR) during or after treatment, which will render the cancer cells resistant not only to the chemotherapy drug being used but also to many other structurally- and mechanically-different chemotherapeutics. In the first project, the main focus was on development of drug resistant cell lines by selection with taxol. Gene changes in the L1T2 cell line after treatment with Taxol was studied. Treatment of L1T2 cells with taxol leads to changes in the expression of ABC transporter proteins, whereas the combination of Taxol with protease inhibitors leads to increased efficacy via inhibition of P-glycoprotein (P-gp). In the second project, we showed that our innovatively-designed Au-loaded poly(lactide-co-glycolic acid) nanoparticles (GPLGA NPs) are able to cross biological barriers and deliver inside the cells without being recognized by the ABC protein transporter. (We focus specifically on P-gp-mediated drug efflux in a model of HEK cell lines.) The concentration of gold was measured using inductively-coupled plasma/mass spectrometry (ICP-MS) after 6- and 24-hour treatment of GPLGA NPs, which did not show significant increase of gold inside the cells in presence of the P-gp inhibitor valspodar. Cancer cells were treated with the GPLGA NPs for 24 hours and then irradiated 5 minutes at 1Wcm-2 using laser settings at 680 or 808 nm. Heat generation in cancer cells, after internalizing GPLGA NPs and laser irradiation, was significant irrespective of laser wavelength. The plasmomic heating response in this in vitro model can be a step closer to overcome MDR. Finally, for the third and last project represented in this dissertation, the focus was on the design and synthesis of innovative, biodegradable PLGA NPs, encapsulated with the platinum(II)-based non-organometallic/non-cyclometalated phosphorescent complex PTA = [Pt(ptp)2], a brightly phosphorescent complex …
The Crucial Role of Solvation Forces in the Steric Stabilization of Nanoplatelets
Article says that the steric stability of inorganic colloidal particles in an apolar solvent is usually described in terms of the balance between three contributions: the van der Waals attraction, the free energy of mixing, and the ligand compression. The authors demonstrate that for sufficiently large nanoplatelets, solvation forces are proportional to the interacting facet area, and their strength is intrinsically tied to the softness of the ligand shell.
Plexcitonic interactions in spherical and bi-pyramidical Au nanoparticles with monolayer WSe₂
Article describes how plasmons associated with zero-dimensional (0D) metal nanoparticles and their synergistic interactions with excitons in two-dimensional (2D) semiconductors offer opportunities for remarkable spectral tunability not otherwise evident in the pristine parent materials, which necessitates an in-depth study elucidating the nature of the plasmonic and excitonic interactions, jointly referred to as plexcitons in order to understand the foundational aspects of the light–matter interactions in hybrid 0D–2D systems. The authors examine the plexcitonic interactions of van der Waals (vdWs) hybrid structures composed of 2D WSe2 and 0D Au nanoparticles (Au-NPs) in their spherical (Au-Sp) and bi-pyramidical (Au-BP) architectures, which demonstrates that geometry-mediated response of the AuNPs provides another degree of freedom to modulate the carrier photodynamics in WSe₂.
Enhanced Corrosion Resistance and Surface Wettability of PVDF/ZnO and PVDF/TiO2 Composite Coatings: A Comparative Study
Article describes how this study aims to enhance the practical performance of PVDF/ZnO and PVDF/TiO2 composite coatings known for their distinctive properties. The coatings, applied through spray coating with PVDF and ZnO or TiO2 nanoparticles on glass, steel, and aluminum substrates, underwent a comprehensive evaluation.
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