Nanoscience and Nanotechnology Commons^™

Bio-Nano Interfaces: Enzyme Immobilization For Biomimetic Energy Harvesting, Rachel Hjelm

Nanoscience and Microsystems ETDs

In the face of todays rapidly growing energy demands accompanied by limited, non-renewable supplies, development of novel energy alternatives that are both renewable and inexpensive has become more important than ever. Development of 3D structures exploring the properties of nano-materials and biological molecules has been shown through the years as an effective path forward for the design of advanced bio-nano architectures for enzymatic fuel cells (EFCs). Despite advantages over conventional fuel cells, EFCs still suffer from several problems including low efficiency and stability. Overcoming these limitations in order to make them more viable for real world application is an ongoing …

Visualizing Mast Cell Activation: Single Molecule Dynamics Of Early Events In Fceri Signaling, Samantha Schwartz

Nanoscience and Microsystems ETDs

Healthy immune cell behavior requires sensitive and robust control over the processes that regulate signal transduction. In this work we employ single molecule fluorescence imaging techniques to quantify adapter protein recruitment, lateral mobility, receptor aggregation, and cytoskeletal organization to create a better understanding of many key processes in immune cell regulation. We focus on understanding the initiating events in FceRI signaling in mast cells. Mast cell signaling encompassing a wide array of cellular outcomes including calcium flux, release of pre-formed inflammatory mediators and the production of cytokines. Careful control over appropriate reactions to external antigens is necessary for mast cells …

Complete Design Methodology Of A Massively Parallel And Pipelined Memristive Stateful Imply Logic Based Reconfigurable Architecture, Kamela Choudhury Rahman

Dissertations and Theses

Continued dimensional scaling of CMOS processes is approaching fundamental limits and therefore, alternate new devices and microarchitectures are explored to address the growing need of area scaling and performance gain. New nanotechnologies, such as memristors, emerge. Memristors can be used to perform stateful logic with nanowire crossbars, which allows for implementation of very large binary networks that can be easily reconfigured. This research involves the design of a memristor-based massively parallel datapath for various applications, specifically SIMD (Single Instruction Multiple Data) like architecture, and parallel pipelines. The dissertation develops a new model of massively parallel memristor-CMOS hybrid datapath architectures at …

Electrically Conductive Cotton Textile And Its Applications, Sicong Liu

Electronic Thesis and Dissertation Repository

Electronic textiles (e-textiles) have been considered as important applications in wearable electronics, which can combine the functionality of smart electronic devices with the comfort and flexibility of stylish clothing. Herein, we have successfully prepared a conductive textile via electroless deposition onto cotton textiles by using a three-step treatment process. The cotton textiles are first dipped in P4VP-SU8 solution to form a uniform layer for the subsequent absorption of silver ions. Then, the cotton textiles are immersed in silver nitrate solution in preparation for the next step electroless deposition. The sheet resistance can be as low as 0.05 Ωsq^-1. …

Calcium Phosphate As A Key Material For Socially Responsible Tissue Engineering, Vuk Uskoković, Victoria M. Wu

Pharmacy Faculty Articles and Research

Socially responsible technologies are designed while taking into consideration the socioeconomic, geopolitical and environmental limitations of regions in which they will be implemented. In the medical context, this involves making therapeutic platforms more accessible and affordable to patients in poor regions of the world wherein a given disease is endemic. This often necessitates going against the reigning trend of making therapeutic nanoparticles ever more structurally complex and expensive. However, studies aimed at simplifying materials and formulations while maintaining the functionality and therapeutic response of their more complex counterparts seldom provoke a significant interest in the scientific community. In this review …

Microstructure And Mechanical Properties Of Nanofiller Reinforced Tantalum-Niobium Carbide Formed By Spark Plasma Sintering, Christopher Charles Rudolf

FIU Electronic Theses and Dissertations

Ultra high temperature ceramics (UHTC) are candidate materials for high temperature applications such as leading edges for hypersonic flight vehicles, thermal protection systems for spacecraft, and rocket nozzle throat inserts due to their extremely high melting points. Tantalum and Niobium Carbide (TaC and NbC), with melting points of 3950°C and 3600°C, respectively, have high resistivity to chemical attack, making them ideal candidates for the harsh environments UHTCs are to be used in. The major setbacks to the implementation of UHTC materials for these applications are the difficulty in consolidating to full density as well as their low fracture toughness. In …

Enhanced Adhesion Of Superhydrophobic Zno Surface, Liqiu Zheng Dr., Chan Kwaichow B.

Georgia Journal of Science

The superhydrophobicity and the strong solid-liquid adhesion of the dually structured ZnO surface are attributed to the suitable size of microstructure and nanostructure. This phenomenon, so different from the Lotus effect, can be called the Petal effect— the super hydrophobicity and the enhanced solid-liquid adhesion coexist on the same surface. The Cassie impregnating model was proposed to understand the underlying reason.

Light-Activated Photocurrent Degradation And Self-Healing In Perovskite Solar Cells, Wanyi Nie, Jean-Christophe Blancon, Amanda J. Neukirch, Kannatassen Appavoo, Hsinhan Tsai, Manish Chhowalla, Muhammad A. Alam, Matthew Y. Sfeir, Claudine Katan, Jacky Even, Sergei Tretiak, Jared J. Crochet, Gautam Gupta, Aditya D. Mohite

Publications and Research

Solution-processed organometallic perovskite solar cells have emerged as one of the most promising thin-film photovoltaic technology. However, a key challenge is their lack of stability over prolonged solar irradiation. Few studies have investigated the effect of light soaking on hybrid perovskites and have attributed the degradation in the optoelectronic properties to photochemical or field-assisted ion migration. Here we show that the slow photocurrent degradation in thin-film photovoltaic devices is due to the formation of light-activated meta-stable deep-level trap states. However, the devices can self-heal completely by resting them in the dark for <1 min or the degradation can be completely prevented by operating the devices at 0°C. We investigate several physical mechanisms to explain the microscopic origin for the formation of these trap states, among which the creation of small polaronic states involving localized cooperative lattice strain and molecular orientations emerges as a credible microscopic mechanism requiring further detailed studies.

Feed-Forward Inhibitory Circuits In Hippocampus And Their Computational Role In Fragile X Syndrome, Sarah Lauren Wahlstrom Helgren

McKelvey School of Engineering Theses & Dissertations

Feed-forward inhibitory (FFI) circuits are canonical neural microcircuits. They are unique in that they are comprised of excitation rapidly followed by a time-locked inhibition. This sequence provides for a powerful computational tool, but also a challenge in the analysis and study of these circuits. In this work, mechanisms and computations of two hippocampal FFI circuits have been examined. Specifically, the modulation of synaptic strength of the excitation and the inhibition is studied during constant-frequency and naturalistic stimulus patterns to reveal how FFI circuit properties and operations are dynamically modulated during ongoing activity. In the first part, the FFI circuit dysfunction …

Focal Adhesion Kinase Regulation In Stem Cell Alignment And Spreading On Nanofibers, Mohammad Nahid Andalib, Jeong Soon Lee, Ligyeom Ha, Yuris A. Dzenis, Jung Yul Lim

Department of Mechanical and Materials Engineering: Faculty Publications

While electrospun nanofibers have demonstrated the potential for novel tissue engineering scaffolds, very little is known about the molecular mechanism of how cells sense and adapt to nanofibers. Here, we revealed the role of focal adhesion kinase (FAK), one of the key molecular sensors in the focal adhesion complex, in regulating mesenchymal stem cell (MSC) shaping on nanofibers. We produced uniaxially aligned and randomly distributed nanofibers from poly(L-lactic acid) to have the same diameters (about 130 nm) and evaluated MSC behavior on these nanofibers comparing with that on flat PLLA control. C3H10T1/2 murine MSCs exhibited upregulations in FAK expression and …

Symbiotic Plasmonic Nanomaterials: Synthesis And Properties, Abhinav Malasi

Doctoral Dissertations

Metal particles of the dimensions of the order of 1 to 100's of nanometers show unique properties that are not clearly evident in their bulk state. These nanoparticles are highly reactive and sensitive to the changes in the vicinity of the particle surface and hence find applications in the field of sensing of chemical and biological agents, catalysis, energy harvesting, data storage and many more. By synthesizing bimetallic nanoparticles, a single nanoparticle can show multifunctional characteristics. The focus of this thesis is to detail the synthesis and understand the properties of bimetallic nanomaterial systems that show interesting optical, chemical, and …

Inter-Droplet Membranes For Mechanical Sensing Applications, Nima Tamaddoni Jahromi

Doctoral Dissertations

This dissertation combines self-assembly phenomena of amphiphilic molecules with soft materials to create and characterize mechanoelectrical transducers and sensors whose sensing elements are thin-film bioinspired membranes comprised of phospholipids or amphiphilic polymers. We show that the structures of these amphiphilic molecules tune the mechanical and electrical properties of these membranes. We show that these properties affect the mechanoelectrical sensing characteristic and range of operation of these membrane transducers. In the experiments, we construct and characterize a membrane-based hair cell embodiment that enables the membrane to be responsive to mechanical perturbations of the hair. The resulting oscillations of membranes formed between …

Numerical And Experimental Studies Of Atomic Layer Deposition For Sustainability Improvement, Dongqing Pan

Theses and Dissertations

Atomic layer deposition (ALD) is an approved nano-scale thin films fabrication technique with remarkable uniformity and conformity in surface geometry. This dissertation presents numerical and experimental studies to investigate the transient physical and chemical ALD process in order to improve its sustainability performance in terms of throughput, wastes and emissions.

To be specific, in this dissertation, the transient process of ALD is studied extensively through both numerical and experimental approaches to find the influential factors on the two main critical sustainability issues: low throughput and negative environmental impacts. Different numerical schemes are developed and studied for ALD process simulations. In …

Fundamental Interdiffusion Analysis Of Ruthenium And Cobalt Films, Bartlet Deprospo

Nanoscale Science & Engineering (discontinued with class year 2014)

No abstract provided.

Gold Nanoparticle Colorimetric Sensing Technology, Eve Borden

Nanoscale Science & Engineering (discontinued with class year 2014)

No abstract provided.

Development And Characterization Of Adhesive Hydrogels For Stem Cell Culture, Erin Byrne Rousseau

Nanoscale Science & Engineering (discontinued with class year 2014)

Pluripotent embryonic stem cells (ESCs) offer the unique capacity to differentiate into almost any cell type and have sweeping implications in both basic research and clinical applications. However, unregulated differentiation can cause issues, preventing ESCs from entering clinical research. In order to maximize ESC growth, three dimensional culturing has been utilized in order to have results more similar to in vivo conditions. In the case of alginate scaffolds, cell adhesion sites are missing from the matrix, leading to differentiation. We propose that the inclusion of adhesive polymer to the alginate scaffold will increase cell attachment and maintain pluripotency. The polymer …

Predicting Structures And Properties Of Transition Metal Dichalcogenide Alloys Using Density Functional Theory, Lucas R. Bruzgulis

Nanoscale Science & Engineering (discontinued with class year 2014)

Workflows for computationally simulating transition metal dichalcogenides using density functional theoretic methods and cluster expansion were established, as implemented in the Quantum ESPRESSO and Alloy Theoretic Automated Toolkit computer codes, respectively. Effects of energy cutoff values and k-point density on convergence of DFT results were investigated for the MoS2 structure, and theoretic band structure calculations for MoS2 and WS2 were performed. The MoXW(1-X)S2 alloy system was also investigated using the maps code in the Alloy Theoretic Automated Toolkit in order to generate a composition vs energy plot. The application of Special Quasi-random Structures to further research into TMDC alloy systems …

Graphene’S Electronic Surface States On Metal Substrates, Alex De Palma

Nanoscale Science & Engineering (discontinued with class year 2014)

Graphene is a 2-­‐D sheet of sp2 bonded carbon atoms with exceptional electrical properties. Particularly, graphene has a very high carrier mobility (~200,000 cm2/V·∙s). This is largely due to graphene’s unique electronic structure, wherein charge carriers are effectively massless Dirac fermions. However, the unique electronic structure of graphene has been shown to be affected by the underlying substrate. In this study, we characterize the electronic structure of graphene on copper. Electron energy loss spectroscopy is employed to observe the surface plasmon excitations of graphene. A small pi plasmon excitation is observed, suggesting that the graphene/Cu interaction is weak and non-­‐covalent. …

Size Controlled Formation Of A Collagen-Based Drug Delivery System, Leonardo Bezerra

Nanoscale Science & Engineering (discontinued with class year 2014)

This study investigates and troubleshoots various factors involved in the generation of collagen-based particles, such as volume of solution, temperature, and incubation time for the purposes of a potential colorectal cancer targeting drug vehicle. The particles were generated via loading into a gel mold and show a 20-200 fold decrease in size compared to those created only under chemical means.

Optimization And Modeling Of An Energy Harvesting Optical Micropropeller For Microfluidic Applications, Jacqueline Elwood

Nanoscale Science & Engineering (discontinued with class year 2014)

The design and materials optimization of a optical micropropeller comprised of silver nanorods on a fused silica substrate was developed. A combination of surface plasmon resonance, thermophoretic and convective forces enable rotation of the micropropeller in an aqueous environment. This work aims to eliminate the dependence of optical micropropellers on the requirement for a light source by relying on a blackbody radiation energy harvesting principle. This energy harvesting principle is able to plasmonically excite noble metal nanorods of a specific aspect ratio at specific wavelengths that correspond to an ambient temperature. By investigating the dependence of the aspect ratio and …