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Full-Text Articles in Nanoscience and Nanotechnology

Polyanhydride Nanoparticles Induce Low Inflammatory Dendritic Cell Activation Resulting In Cd8+ T Cell Memory And Delayed Tumor Progression, Ross Darling, Sujata Senapati, John Christiansen, Luman Liu, Amanda E. Ramer-Tait, Balaji Narasimhan, Michael J. Wannemeuhler Sep 2020

Polyanhydride Nanoparticles Induce Low Inflammatory Dendritic Cell Activation Resulting In Cd8+ T Cell Memory And Delayed Tumor Progression, Ross Darling, Sujata Senapati, John Christiansen, Luman Liu, Amanda E. Ramer-Tait, Balaji Narasimhan, Michael J. Wannemeuhler

Chemical and Biological Engineering Publications

Introduction: Adjuvants and immunotherapies designed to activate adaptive immunity to eliminate infectious disease and tumors have become an area of interest aimed at providing a safe and effective strategy to prevent or eliminate disease. Existing approaches would benefit from the development of immunization regimens capable of inducing efficacious cell-mediated immunity directed toward CD8+ T cell-specific antigens. This goal is critically dependent upon appropriate activation of antigen-presenting cells (APCs) most notably dendritic cells (DCs). In this regard, polyanhydride particles have been shown to be effectively internalized by APCs and induce activation.
Methods: Here, a prophylactic vaccine regimen designed as a single-dose ...


Designing A Reactor Chamber For Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn Merrill, Bingjie Zhang, Jerry Larue Aug 2020

Designing A Reactor Chamber For Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn Merrill, Bingjie Zhang, Jerry Larue

SURF Posters and Papers

Catalysis provides pathways for efficient and selective chemical reactions by lowering the energy barriers for desired products. Gold nanoparticles (AuNPs) show excellent promise as plasmonic catalysts. Plasmonic materials have localized surface plasmon resonances, oscillations of the electron bath at the surface of a nanoparticle, that generate energetically intense electric fields which rapidly decay into energetically excited electrons. The excited electrons have the potential to destabilize atoms strongly bound to the catalysts through occupation of antibonding orbitals. Tuning the antibonding orbitals to make them accessible for occupancy by electrons is achieved by coating the AuNP in a thin layer of another ...


Interfacial And Bulk Assembly Of Anisotropic Gold Nanostructures: Implications For Photonics And Plasmonics, Hyeong Jin Kim, Md Mir Hossen, Andrew C. Hillier, David Vaknin, Surya K. Mallapragada, Wenjie Wang Jul 2020

Interfacial And Bulk Assembly Of Anisotropic Gold Nanostructures: Implications For Photonics And Plasmonics, Hyeong Jin Kim, Md Mir Hossen, Andrew C. Hillier, David Vaknin, Surya K. Mallapragada, Wenjie Wang

Chemical and Biological Engineering Publications

We report on the assembly of polymer-grafted nanostructures at the vapor/aqueous interface and in bulk solutions by using synchrotron X-ray diffraction methods. Triangular- and octahedral-shaped gold nanostructures are synthesized and grafted with polyethylene glycol (referred to as PEG-AuNTs and PEG-AuNOh, respectively) and their suspensions are manipulated with salts, (poly)electrolytes that induce interpolymer complexation and HCl to achieve organized assemblies. The assemblies at the vapor/liquid interface are explored by X-ray reflectivity and grazing incidence small angle X-ray scattering. Results show that the PEG-AuNTs and PEG-AuNOh populate the interface, with some degree of orientation with respect to the liquid ...


Transport Of Artificial Virus-Like Nanocarriers (Avn) Through Intestinal Monolayer Via Microfold Cells, Tianjian Tong, Yijun Qi, Luke Bussiere, Michael J. Wannemeuhler, Cathy L. Miller, Chenxu Yu, Qun Wang Jul 2020

Transport Of Artificial Virus-Like Nanocarriers (Avn) Through Intestinal Monolayer Via Microfold Cells, Tianjian Tong, Yijun Qi, Luke Bussiere, Michael J. Wannemeuhler, Cathy L. Miller, Chenxu Yu, Qun Wang

Agricultural and Biosystems Engineering Publications

Compared with subcutaneous or intramuscular routes for vaccination, vaccine delivery via gastrointestinal mucosa has tremendous potential as it is easy to administer and pain free. Robust immune responses can be triggered successfully once vaccine carried antigen reaches the mucosal associated lymphoid sites (e.g., Peyer’s patches). However, the absence of an efficient delivery method has always been an issue for successful oral vaccine development. In our study, inspired by mammalian orthoreovirus (MRV) transport into gut mucosal lymphoid tissue via Microfold cells (M cells), artificial virus-like nanocarriers (AVN), consisting of gold nanocages functionalized with the 1 protein from mammalian reovirus ...


Surface Chemistry Of Ternary Nanocrystals: Engineering The Deposition Of Conductive Nabis2 Films, Alan M. Medina-Gonzalez, Bryan A. Rosales, Umar H. Hamdeh, Matthew G. Panthani, Javier Vela Jun 2020

Surface Chemistry Of Ternary Nanocrystals: Engineering The Deposition Of Conductive Nabis2 Films, Alan M. Medina-Gonzalez, Bryan A. Rosales, Umar H. Hamdeh, Matthew G. Panthani, Javier Vela

Chemistry Publications

The ability to engineer the surface chemistry of complex ternary nanocrystals is critical to their successful application in photovoltaic, thermoelectric, and other energy conversion devices. For many years, several studies have shed light into the surface chemistry of unary and binary semiconductor nanocrystals, as well as their surface modification with monodentate and multidentate ligands in a variety of applications. In contrast, our understanding of the surface chemistry and ligand modification of ternary and other complex multinary nanocrystals remains relatively limited. Recently, our group reported the synthesis of colloidal NaBiS2 semiconductor nanocrystals with sizes tunable between 2–60 nm, and a ...


Direct Observations Of Field-Intensity-Dependent Dielectric Breakdown Mechanisms In Tio2 Single Nanocrystals, Xinchun Tian, Geoff Lee Brennecka, Xiaoli Tan Jun 2020

Direct Observations Of Field-Intensity-Dependent Dielectric Breakdown Mechanisms In Tio2 Single Nanocrystals, Xinchun Tian, Geoff Lee Brennecka, Xiaoli Tan

Materials Science and Engineering Publications

One of the main challenges for next-generation electric power systems and electronics is to avoid premature dielectric breakdown in insulators and capacitors and to ensure reliable operations at higher electric fields and higher efficiencies. However, dielectric breakdown is a complex phenomenon and often involves many different processes simultaneously. Here we show distinctly different defect-related and intrinsic breakdown processes by studying individual, single-crystalline TiO2 nanoparticles using in situ transmission electron microscopy (TEM). As the applied electric field intensity rises, rutile-to-anatase phase transition, local amorphization/melting, and ablation are identified as the corresponding breakdown processes, the field intensity thresholds of which are ...


Facile Fabrication Of Hierarchical Mof–Metal Nanoparticle Tandem Catalysts For The Synthesis Of Bioactive Molecules, Jingwen Chen, Biying Zhang, Long Qi, Yuchen Pei, Renfeng Nie, Patrick M. Heintz, Xuechen Luan, Zongbi Bao, Qiwei Yang, Qilong Ren, Zhiguo Zhang, Wenyu Huang May 2020

Facile Fabrication Of Hierarchical Mof–Metal Nanoparticle Tandem Catalysts For The Synthesis Of Bioactive Molecules, Jingwen Chen, Biying Zhang, Long Qi, Yuchen Pei, Renfeng Nie, Patrick M. Heintz, Xuechen Luan, Zongbi Bao, Qiwei Yang, Qilong Ren, Zhiguo Zhang, Wenyu Huang

Chemistry Publications

Multifunctional metal–organic frameworks (MOFs) that possess permanent porosity are promising catalysts in organic transformation. Herein, we report the construction of a hierarchical MOF functionalized with basic aliphatic amine groups and polyvinylpyrrolidone-capped platinum nanoparticles (Pt NPs). The postsynthetic covalent modification of organic ligands increases basic site density in the MOF and simultaneously introduces mesopores to create a hierarchically porous structure. The multifunctional MOF is capable of catalyzing a sequential Knoevenagel condensation–hydrogenation–intramolecular cyclization reaction. The unique selective reduction of the nitro group to intermediate hydroxylamine by Pt NPs supported on MOF followed by intramolecular cyclization with a cyano group ...


Chitosan-Adjuvanted Salmonella Subunit Nanoparticle Vaccine For Poultry Delivered Through Drinking Water And Feed, Sankar Renu, Yi Han, Santosh Dhakal, Yashavanth S. Lakshmanappa, Ninoshkaly Feliciano-Ruiz, Sujata Senapati, Balaji Narasimhan, Ramesh Selvaraj, Gourapura J. Renukaradhya May 2020

Chitosan-Adjuvanted Salmonella Subunit Nanoparticle Vaccine For Poultry Delivered Through Drinking Water And Feed, Sankar Renu, Yi Han, Santosh Dhakal, Yashavanth S. Lakshmanappa, Ninoshkaly Feliciano-Ruiz, Sujata Senapati, Balaji Narasimhan, Ramesh Selvaraj, Gourapura J. Renukaradhya

Chemical and Biological Engineering Publications

Poor induction of mucosal immunity in the intestines by current Salmonella vaccines is a challenge to the poultry industry. We prepared and tested an oral deliverable Salmonella subunit vaccine containing immunogenic outer membrane proteins (OMPs) and flagellin (F) protein loaded and F-protein surface coated chitosan nanoparticles (CS NPs) (OMPs-F-CS NPs). The OMPs-F-CS NPs had mean particle size distribution of 514 nm, high positive charge and spherical in shape. In vitro and in vivo studies revealed the F-protein surface coated CS NPs were specifically targeted to chicken immune cells. The OMPs-F-CS NPs treatment of chicken immune cells upregulated TLRs, and Th1 ...


Probing Nanoelectroporation And Resealing Of The Cell Membrane By The Entry Of Ca2+ And Ba2+ Ions, Wenfei Bo, Mantas Silkunas, Uma Mangalanathan, Vitalij Novickij, Maura Casciola, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Andrei G. Pakhomov May 2020

Probing Nanoelectroporation And Resealing Of The Cell Membrane By The Entry Of Ca2+ And Ba2+ Ions, Wenfei Bo, Mantas Silkunas, Uma Mangalanathan, Vitalij Novickij, Maura Casciola, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Andrei G. Pakhomov

Bioelectrics Publications

The principal bioeffect of the nanosecond pulsed electric field (nsPEF) is a lasting cell membrane permeabilization, which is often attributed to the formation of nanometer-sized pores. Such pores may be too small for detection by the uptake of fluorescent dyes. We tested if Ca2+, Cd2+, Zn2+, and Ba2+ ions can be used as nanoporation markers. Time-lapse imaging was performed in CHO, BPAE, and HEK cells loaded with Fluo-4, Calbryte, or Fluo-8 dyes. Ca2+ and Ba2+ did not change fluorescence in intact cells, whereas their entry after nsPEF increased fluorescence within <1 ms. The threshold for one 300-ns pulse was at 1.5–2 kV/cm, much lower than >7 kV/cm for ...


Size-Dependent Inhibitory Effects Of Antibiotic Nanocarriers On Filamentation Of E. Coli, Preeyaporn Songkiatisak, Feng Ding, Pavan Kumar Cherukuri, Xiao-Hong Nancy Xu May 2020

Size-Dependent Inhibitory Effects Of Antibiotic Nanocarriers On Filamentation Of E. Coli, Preeyaporn Songkiatisak, Feng Ding, Pavan Kumar Cherukuri, Xiao-Hong Nancy Xu

Chemistry & Biochemistry Faculty Publications

Multidrug membrane transporters exist in both prokaryotic and eukaryotic cells and cause multidrug resistance (MDR), which results in an urgent need for new and more effective therapeutic agents. In this study, we used three different sized antibiotic nanocarriers to study their mode of action and their size-dependent inhibitory effects against Escherichia coli (E. coli). Antibiotic nanocarriers (AgMUNH–Oflx NPs) with 8.6 × 102, 9.4 × 103 and 6.5 × 105 Oflx molecules per nanoparticle (NP) were prepared by functionalizing Ag NPs (2.4 ± 0.7, 13.0 ± 3.1 and 92.6 ± 4.4 nm) with a ...


Crystallographic Facet Selective Her Catalysis: Exemplified In Fep And Nip2 Single Crystals, Bryan Owens-Baird, Juliana P.S. Sousa, Yasmine Ziouani, Dmitri Y. Petrovykh, Nikolai A. Zarkevich, Duane D. Johnson, Yury V. Kolen'ko, Kirill Kovnir Apr 2020

Crystallographic Facet Selective Her Catalysis: Exemplified In Fep And Nip2 Single Crystals, Bryan Owens-Baird, Juliana P.S. Sousa, Yasmine Ziouani, Dmitri Y. Petrovykh, Nikolai A. Zarkevich, Duane D. Johnson, Yury V. Kolen'ko, Kirill Kovnir

Ames Laboratory Accepted Manuscripts

How the crystal structures of ordered transition-metal phosphide catalysts affect the hydrogen-evolution reaction (HER) is investigated by measuring the anisotropic catalytic activities of selected crystallographic facets on large (mm-sized) single crystals of iron-phosphide (FeP) and monoclinic nickel-diphosphide (m-NiP2). We find that different crystallographic facets exhibit distinct HER activities, in contrast to a commonly held assumption of severe surface restructuring during catalytic activity. Moreover, density-functional-theory-based computational studies show that the observed facet activity correlates well with the H-binding energy to P atoms on specific surface terminations. Direction dependent catalytic properties of two different phosphides with different transition metals, crystal structures, and ...


Quantifying Wicking In Functionlized Surfaces, Maureen Winter, Ryan Regan, Alfred Tsubaki, Craig Zuhlke, Dennis Alexander, George Gogos Apr 2020

Quantifying Wicking In Functionlized Surfaces, Maureen Winter, Ryan Regan, Alfred Tsubaki, Craig Zuhlke, Dennis Alexander, George Gogos

UCARE Research Products

Wicking remains the enigmatic key factor in many research areas. From boiling in power plants, to anti-icing on plane wings, to medical instruments, to heat pipes, efficiency and safety depend on how quickly a surface becomes wet. Yet wicking remains difficult to quantify and define as a property of the surface. This experiment strives to measure the wicking property by examining the rate that a liquid can be pulled out of a container. A superhydrophilic surface is placed in contact with the liquid at the bottom of a tube so that the volume flow rate across the surface can be ...


Effective Dispersion Of Mgo Nanostructure On Biochar Support As A Basic Catalyst For Glucose Isomerization, Season S. Chen, Yang Cao, Daniel C.W. Tsang, Jean-Philippe Tessonnier, Jin Shang, Deyi Hou, Zhengtao Shen, Shicheng Zhang, Yong Sik Ok, Kevin C.-W. Wu Apr 2020

Effective Dispersion Of Mgo Nanostructure On Biochar Support As A Basic Catalyst For Glucose Isomerization, Season S. Chen, Yang Cao, Daniel C.W. Tsang, Jean-Philippe Tessonnier, Jin Shang, Deyi Hou, Zhengtao Shen, Shicheng Zhang, Yong Sik Ok, Kevin C.-W. Wu

Chemical and Biological Engineering Publications

Glucose isomerization to fructose is one of the most important reactions in the field of biomass valorization. We demonstrate wood waste valorization with MgCl2 salt to synthesize an environment-friendly catalyst (i.e., MgO-biochar), which exhibits effective glucose-to-fructose isomerization with over 30% fructose yield and 80% selectivity at only 100 °C for 30 min in water as a green medium. This study highlights that one-step synthesis can effectively disperse and tether MgO nanostructures to the biochar matrix, which displays a significant reduction of Mg leaching compared to MgO-biochars produced by two-step synthesis and pure MgO. The MgCl2 acts as a porogen ...


Enhanced Carrier Transport By Transition Metal Doping In Ws2 Field Effect Transistors, Maomao Liu, Sichen Wei, Simran Shahi, Hemendra Nath Jaiswal, Paolo Paletti, Sara Fathipour, Maja Remskar, Jun Jiao, Wansik Hwang, Fei Yao, Huamin Li Apr 2020

Enhanced Carrier Transport By Transition Metal Doping In Ws2 Field Effect Transistors, Maomao Liu, Sichen Wei, Simran Shahi, Hemendra Nath Jaiswal, Paolo Paletti, Sara Fathipour, Maja Remskar, Jun Jiao, Wansik Hwang, Fei Yao, Huamin Li

Physics Faculty Publications and Presentations

High contact resistance is one of the primary concerns for electronic device applications of two-dimensional (2D) layered semiconductors. Here, we explore the enhanced carrier transport through metal–semiconductor interfaces in WS2 field effect transistors (FETs) by introducing a typical transition metal, Cu, with two different doping strategies: (i) a “generalized” Cu doping by using randomly distributed Cu atoms along the channel and (ii) a “localized” Cu doping by adapting an ultrathin Cu layer at the metal–semiconductor interface. Compared to the pristine WS2 FETs, both the generalized Cu atomic dopant and localized Cu contact decoration can provide a ...


Formation Of Size And Density Controlled Nanostructures By Galvanic Displacement, Minh Tran, Sougata Roy, Steven Kmiec, Alison Whale, Steve W. Martin, Sriram Sundararajan, Sonal Padalkar Mar 2020

Formation Of Size And Density Controlled Nanostructures By Galvanic Displacement, Minh Tran, Sougata Roy, Steven Kmiec, Alison Whale, Steve W. Martin, Sriram Sundararajan, Sonal Padalkar

Mechanical Engineering Publications

Gold (Au) and copper (Cu)-based nanostructures are of great interest due to their applicability in various areas including catalysis, sensing and optoelectronics. Nanostructures synthesized by the galvanic displacement method often lead to non-uniform density and poor size distribution. Here, density and size-controlled synthesis of Au and Cu-based nanostructures was made possible by galvanic displacement with limited exposure to hydrofluoric (HF) acid and the use of surfactants like L-cysteine (L-Cys) and cetyltrimethylammonium bromide (CTAB). An approach involving cyclic exposure to HF acid regulated the nanostructure density. Further, the use of surfactants generated monodisperse nanoparticles in the initial stages of the ...


High-Throughput Synthesis And Screening Of Rapidly-Degrading Polyanhydride Nanoparticles, Adam S. Mullis, Sarah J. Jacobson, Balaji Narasimhan Mar 2020

High-Throughput Synthesis And Screening Of Rapidly-Degrading Polyanhydride Nanoparticles, Adam S. Mullis, Sarah J. Jacobson, Balaji Narasimhan

Chemical and Biological Engineering Publications

Combinatorial techniques can accelerate the discovery and development of polymeric nanodelivery devices by pairing high-throughput synthesis with rapid materials characterization. Biodegradable polyanhydrides demonstrate tunable release, high cellular internalization, and dose sparing properties when used as nanodelivery devices. This nanoparticle platform shows promising potential for small molecule drug delivery, but the pace of understanding and rational design of these nanomedicines is limited by the low throughput of conventional characterization. This study reports the use of a high-throughput method to synthesize libraries of a newly synthesized, rapidly-eroding polyanhydride copolymer based on 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane (CPTEG) and sebacic acid (SA) monomers ...


Intermetallic Nanocatalysts From Heterobimetallic Group 10–14 Pyridine-2-Thiolate Precursors, Carena L. Daniels, Megan Knobeloch, Philip Yox, Marquix A.S. Adamson, Yunhua Chen, Rick W. Dorn, Hao Wu, Guoquan Zhou, Huajun Fan, Aaron J. Rossini, Javier Vela Mar 2020

Intermetallic Nanocatalysts From Heterobimetallic Group 10–14 Pyridine-2-Thiolate Precursors, Carena L. Daniels, Megan Knobeloch, Philip Yox, Marquix A.S. Adamson, Yunhua Chen, Rick W. Dorn, Hao Wu, Guoquan Zhou, Huajun Fan, Aaron J. Rossini, Javier Vela

Chemistry Publications

Intermetallic compounds are atomically ordered inorganic materials containing two or more transition metals and main-group elements in unique crystal structures. Intermetallics based on group 10 and group 14 metals have shown enhanced activity, selectivity, and durability in comparison to simple metals and alloys in many catalytic reactions. While high-temperature solid-state methods to prepare intermetallic compounds exist, softer synthetic methods can provide key advantages, such as enabling the preparation of metastable phases or of smaller particles with increased surface areas for catalysis. Here, we study a generalized family of heterobimetallic precursors to binary intermetallics, each containing a group 10 metal and ...


The Surface Termination Of Cspbbr3 Perovskite Quantum Dots Determined By Solid-State Nmr Spectroscopy, Yunhua Chen, Sara R. Smock, Anne H. Flintgruber, Frederic A. Perras, Richard L. Brutchey, Aaron J. Rossini Mar 2020

The Surface Termination Of Cspbbr3 Perovskite Quantum Dots Determined By Solid-State Nmr Spectroscopy, Yunhua Chen, Sara R. Smock, Anne H. Flintgruber, Frederic A. Perras, Richard L. Brutchey, Aaron J. Rossini

Chemistry Publications

Cesium lead halide perovskite quantum dots (QDs) have gained significant attention as next-generation optoelectronic materials; however, their properties are highly dependent on their surface chemistry. The surfaces of cuboidal CsPbBr3 QDs have been intensively studied by both theoretical and experimental techniques, but fundamental questions still remain about the atomic termination of the QDs. The binding sites and modes of ligands at the surface remain unproven. Herein, we demonstrate that solid-state NMR spectroscopy allows the unambiguous assignments of organic surface ligands via 1H, 13C, and 31P NMR. Surface-selective 133Cs solid-state NMR spectra show the presence of an additional 133Cs NMR signal ...


Identifying The Molecular Edge Termination Of Exfoliated Hexagonal Boron Nitride Nanosheets With Solid-State Nmr Spectroscopy And Plane-Wave Dft Calculations, Rick W. Dorn, Matthew J. Ryan, Tae-Hoon Kim, Tian Wei Goh, Patrick M. Heintz, Lin Zhou, Wenyu Huang, Aaron J. Rossini Feb 2020

Identifying The Molecular Edge Termination Of Exfoliated Hexagonal Boron Nitride Nanosheets With Solid-State Nmr Spectroscopy And Plane-Wave Dft Calculations, Rick W. Dorn, Matthew J. Ryan, Tae-Hoon Kim, Tian Wei Goh, Patrick M. Heintz, Lin Zhou, Wenyu Huang, Aaron J. Rossini

Chemistry Publications

Hexagonal boron nitride nanosheets (h-BNNS), the isoelectronic analog to graphene, have received interest over the past decade due to their high thermal oxidative resistance, high bandgap, catalytic activity, and low cost. The functional groups that terminate boron and nitrogen zigzag and/or armchair edges directly affect their chemical, physical, and electronic properties. However, an understanding of the molecular edge termination present in h-BNNS is lacking. Here, high-resolution magic-angle spinning (MAS) solid-state NMR (SSNMR) spectroscopy, and plane-wave density-functional theory (DFT) calculations are used to determine the molecular edge termination in exfoliated h-BNNS. 1H → 11B cross-polarization MAS (CPMAS) SSNMR ...


A Single Dose Polyanhydride-Based Nanovaccine Against Paratuberculosis Infection, Akanksha Thukral, Kathleen Ross, Chungyi Hansen, Yashdeep Phanse, Balaji Narasimhan, Howard Steinberg, Adel M. Talaat Feb 2020

A Single Dose Polyanhydride-Based Nanovaccine Against Paratuberculosis Infection, Akanksha Thukral, Kathleen Ross, Chungyi Hansen, Yashdeep Phanse, Balaji Narasimhan, Howard Steinberg, Adel M. Talaat

Chemical and Biological Engineering Publications

Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) causes Johne’s disease in ruminants and is characterized by chronic gastroenteritis leading to heavy economic losses to the dairy industry worldwide. The currently available vaccine (inactivated bacterin in oil base) is not effective in preventing pathogen shedding and is rarely used to control Johne’s disease in dairy herds. To develop a better vaccine that can prevent the spread of Johne’s disease, we utilized polyanhydride nanoparticles (PAN) to encapsulate mycobacterial antigens composed of whole cell lysate (PAN-Lysate) and culture filtrate (PAN-Cf) of M. paratuberculosis. These nanoparticle-based vaccines (i.e., nanovaccines) were well ...


Shapes Of Fe Nanocrystals Encapsulated At The Graphite Surface, Ann Lii-Rosales, Yong Han, Scott E. Julien, Olivier Pierre-Louis, Dapeng Jing, Kai-Tak Wan, Michael C. Tringides, James W. Evans, Patricia A. Thiel Feb 2020

Shapes Of Fe Nanocrystals Encapsulated At The Graphite Surface, Ann Lii-Rosales, Yong Han, Scott E. Julien, Olivier Pierre-Louis, Dapeng Jing, Kai-Tak Wan, Michael C. Tringides, James W. Evans, Patricia A. Thiel

Chemistry Publications

We describe and analyze in detail the shapes of Fe islands encapsulated under the top graphene layers in graphite. Shapes are interrogated using scanning tunneling microscopy. The main outputs of the shape analysis are the slope of the graphene membrane around the perimeter of the island, and the aspect ratio of the central metal cluster. Modeling primarily uses a continuum elasticity (CE) model. As input to the CE model, we use density functional theory to calculate the surface energy of Fe, and the adhesion energies between Fe and graphene or graphite. We use the shaft-loaded blister test (SLBT) model to ...


In-Situ Gold-Ceria Nanoparticles: Superior Optical Fluorescence Quenching Sensor For Dissolved Oxygen, Nader Shehata, Ishac Kandas, Effat Samir Feb 2020

In-Situ Gold-Ceria Nanoparticles: Superior Optical Fluorescence Quenching Sensor For Dissolved Oxygen, Nader Shehata, Ishac Kandas, Effat Samir

Electrical & Computer Engineering Faculty Publications

Cerium oxide (ceria) nanoparticles (NPs) have been proved to be an efficient optical fluorescent material through generating visible emission (~530 nm) under violet excitation. This feature allowed ceria NPs to be used as an optical sensor via the fluorescence quenching Technique. In this paper, the impact of in-situ embedded gold nanoparticles (Au NPs) inside ceria nanoparticles was studied. Then, gold–ceria NPs were used for sensing dissolved oxygen (DO) in aqueous media. It was observed that both fluorescence intensity and lifetime were changed due to increased concentration of DO. Added gold was found to enhance the sensitivity of ceria to ...


Multimodal Multiplexed Immunoimaging With Nanostars To Detect Multiple Immunomarkers And Monitor Response To Immunotherapies, Yu-Chuan Ou, Xiaona Wen, Christopher A. Johnson, Daniel Shae, Oscar D. Ayala, Joseph A. Webb, Eugene C. Lin, Rossane C. Delapp, Kelli L. Boyd, Ann Richmond, Anita Mahadevan-Jansen, Marjan Rafat, John T. Wilson, Justin M. Balko, Mohammed N. Tantawy, Anna E. Vilgelm, Rizia Bardhan Jan 2020

Multimodal Multiplexed Immunoimaging With Nanostars To Detect Multiple Immunomarkers And Monitor Response To Immunotherapies, Yu-Chuan Ou, Xiaona Wen, Christopher A. Johnson, Daniel Shae, Oscar D. Ayala, Joseph A. Webb, Eugene C. Lin, Rossane C. Delapp, Kelli L. Boyd, Ann Richmond, Anita Mahadevan-Jansen, Marjan Rafat, John T. Wilson, Justin M. Balko, Mohammed N. Tantawy, Anna E. Vilgelm, Rizia Bardhan

Chemical and Biological Engineering Publications

The overexpression of immunomarker programmed cell death protein 1 (PD-1) and engagement of PD-1 to its ligand, PD-L1, are involved in the functional impairment of cluster of differentiation 8+ (CD8+) T cells, contributing to cancer progression. However, heterogeneities in PD-L1 expression and variabilities in biopsy-based assays render current approaches inaccurate in predicting PD-L1 status. Therefore, PD-L1 screening alone is not predictive of patient response to treatment, which motivates us to simultaneously detect multiple immunomarkers engaged in immune modulation. Here, we have developed multimodal probes, immunoactive gold nanostars (IGNs), that accurately detect PD-L1+ tumor cells and CD8+ T cells simultaneously in ...


Unusual Effect Of Iodine Ions On The Self-Assembly Of Poly(Ethylene Glycol)-Capped Gold Nanoparticles, Wenjie Wang, Hyeong Jin Kim, Wei Bu, Surya Mallapragada, David Vaknin Jan 2020

Unusual Effect Of Iodine Ions On The Self-Assembly Of Poly(Ethylene Glycol)-Capped Gold Nanoparticles, Wenjie Wang, Hyeong Jin Kim, Wei Bu, Surya Mallapragada, David Vaknin

Chemical and Biological Engineering Publications

We use synchrotron X-ray reflectivity and grazing incidence small-angle X-ray scattering to investigate the surface assembly of the polyethylene glycol (PEG) grafted gold nanoparticles (PEG-AuNPs) induced by different salts. We find that NaCl and CsCl behave as many other electrolytes, namely drive the PEG-AuNPs to the vapor/suspension interface to form a layer of single particle depth and organize them into very high quality two-dimensional (2D) hexagonal crystals. By contrast, NaI induces the migration of PEG-AuNPs to the aqueous surface at much higher surface densities than the other salts (at similar concentrations). The resulting 2D ordering at moderate NaI concentrations ...


Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, Meikun Shen, Tianben Ding, Steven T. Hartman, Fudong Wang, Christina Krucylak, Zheyu Wang, Che Tan, Bo Yin, Rohan Mishra, Matthew D. Lew, Bryce Sadtler Jan 2020

Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, Meikun Shen, Tianben Ding, Steven T. Hartman, Fudong Wang, Christina Krucylak, Zheyu Wang, Che Tan, Bo Yin, Rohan Mishra, Matthew D. Lew, Bryce Sadtler

Electrical & Systems Engineering Publications and Presentations

Defect engineering is a strategy that has been widely used to design active semiconductor photocatalysts. However, understanding the role of defects, such as oxygen vacancies, in controlling photocatalytic activity remains a challenge. Here, we report the use of chemically triggered fluorogenic probes to study the spatial distribution of active regions in individual tungsten oxide nanowires using super-resolution fluorescence microscopy. The nanowires show significant heterogeneity along their lengths for the photocatalytic generation of hydroxyl radicals. Through quantitative, coordinate-based colocalization of multiple probe molecules activated by the same nanowires, we demonstrate that the nanoscale regions most active for the photocatalytic generation of ...


Multi-Well Plate Channel Device With Reversible Seals, Haipeng Zhang, Timothy Wei, Sangjin Ryu Jan 2020

Multi-Well Plate Channel Device With Reversible Seals, Haipeng Zhang, Timothy Wei, Sangjin Ryu

Mechanical & Materials Engineering Faculty Publications

Atherosclerosis is a cardiovascular disease which causes over 26,000 yearly deaths in the United States. This disease involves accumulation of substances in arterial walls (or plaques) that occurs frequently to arterial regions experiencing low shear stress, such as bends and bifurcations. A possible reason of plaque growth in arterial walls is the change of endothelial cell (EC)’s shape, which is related to fluid shear stresses tangentially acting on intimal layer (the EC surface) of the arterial wall. Lambert et al. studied the relationship between EC shape and shear stress (Lambert et al., 2019) using a BioFlux system (Fluxion ...


Nanothermomechanical And And Or Logic Gates, Ahmed Hamed, Sidy Ndao Jan 2020

Nanothermomechanical And And Or Logic Gates, Ahmed Hamed, Sidy Ndao

Mechanical & Materials Engineering Faculty Publications

Today’s electronics cannot perform in harsh environments (e.g., elevated temperatures and ionizing radiation environments) found in many engineering applications. Based on the coupling between near-field thermal radiation and MEMS thermal actuation, we presented the design and modeling of NanoThermoMechanical AND, OR, and NOT logic gates as an alternative, and showed their ability to be combined into a full thermal adder to perform complex operations. in this work, we introduce the fabrication and characterization of the first ever documented Thermal AND and OR logic gates. Theresults show thermal logic operations can be achieved successfully through demonstrated and easy-to- manufacture ...


Three-Dimensional Characterization Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer In Patients Following Lumbar Puncture, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu Jan 2020

Three-Dimensional Characterization Of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer In Patients Following Lumbar Puncture, Junfei Tong, Pengfei Dong, Sachin Kedar, Deepta Ghate, Linxia Gu

Mechanical & Materials Engineering Faculty Publications

Purpose: To develop and test an innovative semi-automatic method for quantifying the three-dimensional morphology of the peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer, with application to lumbar puncture (LP) patients. Methods: Nineteen patients undergoing LP were recruited. The optic nerve head images of both eyes were acquired in 12 radial directions using optical coherence tomography (OCT) before and after LP. For each OCT image, the ppRPE/BM layer was automatically segmented with manual corrections by independent graders when necessary. The linear regression model of the ppRPE/BM layer was fitted using the least squares approach, and the ppRPE/BM ...


Additive Manufacturing Of Magnesium Alloys, Rakeshkumar Karunakaran, Sam Ortgies, Ali Tamayol, Florin Bobaru, Michael P. Sealy Jan 2020

Additive Manufacturing Of Magnesium Alloys, Rakeshkumar Karunakaran, Sam Ortgies, Ali Tamayol, Florin Bobaru, Michael P. Sealy

Mechanical & Materials Engineering Faculty Publications

Magnesium alloys are a promising new class of degradable biomaterials that have a similar stiffness to bone, which minimizes the harmful effects of stress shielding. Use of biodegradable magnesium implants eliminates the need for a second surgery for repair or removal. There is a growing interest to capitalize on additive manufacturing's unique design capabilities to advance the frontiers of medicine. However, magnesium alloys are difficult to 3D print due to the high chemical reactivity that poses a combustion risk. Furthermore, the low vaporization temperature of magnesium and common biocompatible alloying elements further increases the difficulty to print fully dense ...


Passivation Of Defects In Perovskite Materials For Improved Solar Cell Efficiency And Stability, Jinsong Huang, Xiaopeng Zheng Jan 2020

Passivation Of Defects In Perovskite Materials For Improved Solar Cell Efficiency And Stability, Jinsong Huang, Xiaopeng Zheng

Mechanical & Materials Engineering Faculty Publications

Semiconductor devices, and methods of forming the same, include a cathode layer, an anode layer, and an active layer disposed between the cathode layer and the anode layer, wherein the active layer includes a perovskite layer. A passivation layer is disposed directly on a surface of the active layer between the cathode layer and the active layer, the passivation layer including a layer of material that passivates both cationic and anionic defects in the surface of the active layer.