Browsing by Subject "nanotechnology"
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Item Dissecting Transient Protein Interactions Implicated in Cardiovascular Disease: G Protein-Coupled Receptors and Cardiac Myosin-Binding Protein C(2021-10) Touma, AnjaWeak, transient protein-protein interactions in the cell are being increasingly appreciated, yet characterization of these interactions presents a unique challenge. We have used protein engineering techniques, including ER/K α-helical linkers and DNA nanotechnology, to characterize G protein-coupled receptor (GPCR) and cardiac myosin-binding protein C (cMyBP-C) interactions.The cellular environment can have a significant impact on GPCR signaling and functional selectivity. Our lab has found that GPCR interactions with non-cognate G-proteins can enhance, or ‘prime’, signaling through the canonical pathway. To investigate the impact of non-cognate interactions on signaling in two promiscuous Gi-coupled receptors, adenosine type 1 (A1R) and cannabinoid type 1 (CB1), we utilized a variation of the Systematic Protein Affinity Strength Modulation (SPASM) approach to observe the impact on downstream signaling in live cells. To the C-terminus of intact A1R or CB1, we tethered native G-peptides (s-pep, i-pep, and q-pep) derived from the Gα subunit of G-proteins. We found that i-pep and q-pep enhanced Gi signaling while suppressing Gq signaling. This study provides an initial model for the impact of G-peptide interactions in Gi-coupled receptors, and highlights the potential of G-peptide interactions to enhance receptor specificity. CMyBP-C is an important regulator of cardiac muscle contraction and is commonly implicated in hypertrophic cardiomyopathy (HCM). However, the mechanism of regulation by cMyBP-C remains unclear due to experimental challenges in dissecting these weak, transient interactions. In this study we utilized a nanosurf assay, containing a synthetic β-cardiac myosin thick filament, to systematically probe cMyBP-C interactions with actin and myosin. We recapitulated inhibition of β-cardiac myosin HMM nanotube motility by C0-C2 and C1-C2 N-terminal fragments. Equivalent inhibition of an β-cardiac myosin S1 construct suggests the actin-cMyBP-C interaction dominates this inhibitory mechanism. We found that a C0-C1f fragment lacking the majority of the M-domain did not inhibit β-cardiac myosin nanotube motility, confirming the importance of the M-domain in regulatory interactions. Release of inhibition by phosphomimetic fragments further highlights the importance of the phosphorylatable serines in the regulatory M-domain. These results shed light on the mechanism of cMyBP-C and highlight the utility of the nanosurf assay for precisely manipulating and defining transient protein interactions.Item Nanoparticle Transformations and Toxicity: Impact of Complex Metal Oxide Nanoparticles, Experimental Tools, and Methods for Communicating Nanotechnology to the Public(2020-11) Hudson-Smith, NatalieDue to the unique and advantageous physiochemical properties of nanoparticles, they have been increasingly incorporated into consumer products and emerging technologies. The manufacture, wear and tear of use, and disposal of these nano-enabled products will likely result in the release of nanoparticles into the environment. Unfortunately, environmental response and regulation, as well as public awareness, has lagged behind the development and inclusion of nanoparticles into products. In recent years, there have been advances in understanding the mechanisms of toxicity to many nanoparticle types to model organisms in lab conditions. However, there is a still a need to advance these understandings of interaction with and toxicity to organisms to more closely represent the conditions in the environment, including their transformations in complex, protein-containing media and their toxicity towards communities of organisms as opposed to single model species.Chapter One outlines the basis for this work, including the conclusions of previous work in identifying the mechanisms of toxicity of an energy storage nanomaterial, NMC, and highlights some of the challenges in communicating the advances in nanotechnology research to the public. Chapter Two illustrates the role of nanoparticle morphology and surface area in toxicity. Three morphologies of NMC, with the same chemical composition, are evaluated for toxicity. Ultimately, toxicity of the materials is shown to be most predicted by surface area due to the correlation between surface area and dissolution. In Chapter Three, the formation of a protein corona on these same three morphologies of NMC is explored. The formation of a protein corona has been shown to impact the transformations of nanoparticles and often, mitigate their toxicity. Four environmentally relevant proteins and a model protein are studied. Preliminary results show that surface area does not predict protein corona formation for these NMC materials it predicted toxicity. Additionally, results suggest that protein corona formation on NMC may not mitigate toxicity for this class of nanomaterials. In Chapter Four, advances in methodology for studying nanomaterial toxicity in poly-microbial communities are demonstrated. Nanomaterials have been shown to induce dysbiosis in microbiota and may have a different impact of poly-bacterial communities than they do on individual monocultures of the species that make up such communities. However, most techniques to study nanomaterial impacts on communities are expensive and labor intensive. Here, modifications for a method previously established to assess nanomaterial toxicity to bacteria are presented. Chapters Five, Six, and Seven focus on scientific communication about sustainability and nanotechnology to students and the public. Chapter Five presents a module with videos paired with hands-on demonstrations for explaining the chemistry behind climate change. Chapter Six presents a low-cost, model transmission electron microscope (TEM) that students can use to make pseudo-micrographs. Evaluations of this model and activity show that it is effective in explaining this characterization technique and engaging for students. Chapter Seven presents the development of a text-based adventure game that leads the player through a nano-scale world. These modules are all suitable for scientific communications or teaching and provide new ways to communicate modern science, particularly nanotechnology, to the public.Item Wave-Based Computer Graphic Light Modeling with Applications to Computer Aided Design(2016-08) Musbach, AveryThis work demonstrates the utility of wave-based optics in computer graphics. Whereas computer graphics is ordinarily done with mostly ray-based optics and relatively little wave-based optics, this research illustrates the possibility of creating pictures using only wave-based optics and no ray-based optics. Also, ray-based optics and wave-based optics are combined to produce images that demonstrate how an understanding of both approaches, using only ray-based optics and using only wave-based optics, gives the perspective needed to make a judgment about what is truly a good middle ground. This improved understanding of physically based rendering is leveraged for computer aided design. Pure wave-based optics is applied to nanotechnology with a focus on plasmonic biosensing. Then a healthy balance of ray-based optics and wave-based optics drives computer aided design of car paint. To start, light is simulated with the well-established finite difference time domain method for solving Maxwell's equations. Maxwell's equations are a tightly coupled system of differential equations that describe electromagnetic radiation, and this expression lies at the heart of wave-based optics because light waves are electromagnetic waves. This straightforward numerical solution scheme is shown to constitute a rendering algorithm, proving that it is possible to synthesize an image without using ray-based optics at all. The approach is also shown to be useful for making a shader which can be employed in a ray-based rendering algorithm. Toward computer aided design, the focus is on photonic crystals which can be modeled by a recently proposed high order perturbation scheme that is more efficient than the broadly applicable finite difference time domain method. The algorithm is parallelized to take advantage of a CPU with multiple cores and to allow the algorithm to run at interactive rates. The computation speed is leveraged to deliver real time feedback in a computer aided design system for nanotechnology. Spectral reflectance plots are continuously updated during click-and-drag operations that modify the geometry profile of a nanostructure. The high order perturbation scheme is then combined with a path tracer to facilitate computer aided design for car paint. This contribution places more serious demands on the high order perturbation scheme, namely three dimensions and multiple layers, making real time performance more difficult. Real time feedback is achieved partly by precomputation and partly because in simple cases, commonly occurring in car paint, the high order perturbation scheme reduces to the Fresnel equations for multilayer thin film interference. A new paint product with a novel color appearance is proposed. Supplementary material: butterfly.mov is a video portraying a morpho butterfly sitting on one of the leaves of a plant and flapping its wings to show off the iridescence modeled in this work. This animation was created with a shader based on the finite difference time domain method for Maxwell's equations.