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Articles 1 - 30 of 123

Full-Text Articles in Biomedical Engineering and Bioengineering

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 ...


Gravity-Drawing Flexible Silicone Filaments As Fiber Optics And Model Foldamers, Katherine Snell Jan 2020

Gravity-Drawing Flexible Silicone Filaments As Fiber Optics And Model Foldamers, Katherine Snell

CMC Senior Theses

Here, we present a method of gravity-drawing polydimethylsiloxane (PDMS) silicone fibers with application as fiber optics and as model foldamers. Beginning as a viscous liquid, PDMS is cured using heat until its measured viscosity reaches 4000 mPa•s. The semi-cured elastomer is then extruded through a tube furnace to produce thin (diameters on the order of hundred micrometers) filaments with scalable lengths. PDMS is biocompatible, gas-permeable, flexible, and hydrophobic. Additionally, the PDMS surface hydrophobicity can be modified via UV exposure, O2 plasma, and corona discharge. We demonstrate the patternibility (i.e patterns of hydrophobicity) of PDMS fibers, adding complexity to ...


Synthesis And Applications Of Theranostic Oligonucleotides Carrying Multiple Fluorine Atoms, Valeriy G. Metelev, Alexei A. Bogdanov Jan 2020

Synthesis And Applications Of Theranostic Oligonucleotides Carrying Multiple Fluorine Atoms, Valeriy G. Metelev, Alexei A. Bogdanov

Open Access Articles

The use of various oligonucleotide (ON) syntheses and post-synthetic strategies for targeted chemical modification enables improving their efficacy as potent modulators of gene expression levels in eukaryotic cells. However, the search still continues for new approaches designed for increasing internalization, lysosomal escape, and tissue specific delivery of ON. In this review we emphasized all aspects related to the synthesis and properties of ON derivatives carrying multifluorinated (MF) groups. These MF groups have unique physico-chemical properties because of their simultaneous hydrophobicity and lipophobicity. Such unusual combination of properties results in the overall modification of ON mode of interaction with the cells ...


Fluoride Removal From Water Using A 3d Printed Calcium Carbonate Filter, Sophia Bakar, David Kahler, Benjamin S. Goldschmidt May 2019

Fluoride Removal From Water Using A 3d Printed Calcium Carbonate Filter, Sophia Bakar, David Kahler, Benjamin S. Goldschmidt

Undergraduate Research and Scholarship Symposium

Groundwater containing high concentrations of fluoride is the most common source of drinking water in rural areas in parts of east Africa, India, and China. The elevated levels of fluoride cause skeletal and dental fluorosis, which is the weakening and decay of bone structures due to the leeching of calcium from the body as calcium and fluoride bond by the process of adsorption. Over 150 million people are suffering from some form of fluorosis due to the consumption of groundwater. Calcium carbonate has been demonstrated to influence fluoride removal in several forms. To make fluoride removal a cost-effective and user-friendly ...


Defining Cell Cluster Size By Dielectrophoretic Capture At An Array Of Wireless Electrodes Of Several Distinct Lengths, Joseph T. Banovetz, Min Li, Darshna Pagariya, Sungu Kim, Baskar Ganapathysubramanian, Robbyn Anand Apr 2019

Defining Cell Cluster Size By Dielectrophoretic Capture At An Array Of Wireless Electrodes Of Several Distinct Lengths, Joseph T. Banovetz, Min Li, Darshna Pagariya, Sungu Kim, Baskar Ganapathysubramanian, Robbyn Anand

Chemistry Publications

Clusters of biological cells play an important role in normal and disease states, such as in the release of insulin from pancreatic islets and in the enhanced spread of cancer by clusters of circulating tumor cells. We report a method to pattern cells into clusters having sizes correlated to the dimensions of each electrode in an array of wireless bipolar electrodes (BPEs). The cells are captured by dielectrophoresis (DEP), which confers selectivity, and patterns cells without the need for physical barriers or adhesive interactions that can alter cell function. Our findings demonstrate that this approach readily achieves fine control of ...


Deswelling Induced Morphological Changes In Dual Ph And Temperature Responsive Ultra-Low Crosslinked Poly (N-Isopropyl Acrylamide)-Co-Acrylic Acid Microgels, Molla R. Islam, Maddie Tumbarello, L. Andrew Lyon Mar 2019

Deswelling Induced Morphological Changes In Dual Ph And Temperature Responsive Ultra-Low Crosslinked Poly (N-Isopropyl Acrylamide)-Co-Acrylic Acid Microgels, Molla R. Islam, Maddie Tumbarello, L. Andrew Lyon

Engineering Faculty Articles and Research

Poly(N-isopropylacrylamide) microgels prepared without exogenous cross-linker are extremely “soft” as a result of their very low cross-linking density, with network connectivity arising only from the self-crosslinking of pNIPAm chains. As a result of this extreme softness, our group and others have taken interest in using these materials in a variety of bioengineering applications, while also pursuing studies of their fundamental properties. Here, we report deswelling triggered structural changes in poly(N-isopropylacrylamide-co-acrylic acid) (ULC10AAc) microgels prepared by precipitation polymerization. Dynamic light scattering suggests that the deswelling of these particles not only depends on the collapse of ...


Development Of In Situ Forming Hydrogels For Intra-Articular Drug Delivery, Andy Prince Feb 2019

Development Of In Situ Forming Hydrogels For Intra-Articular Drug Delivery, Andy Prince

Electronic Thesis and Dissertation Repository

Hydrogels are 3-dimensional crosslinked polymer networks that can absorb significant amounts of water. The physical properties associated with hydrogels affords them resemblance to biological tissues making them good candidates for biomedical applications. Many pharmaceuticals, specifically non-steroidal anti-inflammatory drugs (NSAIDs), have poor aqueous solubility, which limits their bioavailability and efficacy. People suffering from chronic osteoarthritis (OA) are required to frequently take large doses to mitigate pain, which can lead to serious side effects. Hydrogels are good strategies to deliver NSAIDs via articular injection because they can form solid gels in situ. This thesis describes the synthesis, formulation, mechanical testing, in vitro ...


Design And Synthesis Of Multivalent Α-1,2-Trimannose-Linked Bioerodible Microparticles For Applications In Immune Response Studies Of Leishmania Major Infection, Chelsea L. Rintelmann, Tara Grinnage-Pulley, Kathleen Ross, Daniel E. K. Kabotso, Angela Toepp, Anne Cowell, Christine Petersen, Balaji Narasimhan, Nicola Pohl Jan 2019

Design And Synthesis Of Multivalent Α-1,2-Trimannose-Linked Bioerodible Microparticles For Applications In Immune Response Studies Of Leishmania Major Infection, Chelsea L. Rintelmann, Tara Grinnage-Pulley, Kathleen Ross, Daniel E. K. Kabotso, Angela Toepp, Anne Cowell, Christine Petersen, Balaji Narasimhan, Nicola Pohl

Chemical and Biological Engineering Publications

Leishmaniasis, a neglected tropical disease, currently infects approximately 12 million people worldwide with 1 to 2 million new cases each year in predominantly underdeveloped countries. The treatment of the disease is severely underdeveloped due to the ability of the Leishmania pathogen to evade and abate immune responses. In an effort to develop anti-leishmaniasis vaccines and adjuvants, novel carbohydrate-based probes were made to study the mechanisms of immune modulation. In this study, a new bioerodible polyanhydride microparticle was designed and conjugated with a glycodendrimer molecular probe. This molecular probe incorporates a pathogen-like multivalent display of α-1,2-trimannose, for which a more ...


Spatial Fingerprinting Of Biogenic And Anthropogenic Volatile Organic Compounds In An Arid Unsaturated Zone, Christopher T. Green, Wentai Luo, Christopher H. Conaway, Karl B. Haase, Ronald J. Baker Jan 2019

Spatial Fingerprinting Of Biogenic And Anthropogenic Volatile Organic Compounds In An Arid Unsaturated Zone, Christopher T. Green, Wentai Luo, Christopher H. Conaway, Karl B. Haase, Ronald J. Baker

Chemistry Faculty Publications and Presentations

Subsurface volatile organic compounds (VOCs) can pose risks to human and environmental health and mediate biological processes. Volatile organic compounds have both anthropogenic and biogenic origins, but the relative importance of these sources has not been explored in subsurface environments. This study synthesized 17 yr of VOC data from the Amargosa Desert Research Site in Nevada with the goal of improving understanding of spatial and temporal variations that distinguish sources of VOCs from a landfill and from ambient sources including biogenic VOCs (bVOCs). Gas samples were collected from 1999 to 2016 from an array of shallow sample points (0.5- ...


Kcnq1/Kcne1 Interaction In The Cardiac Iks Channel And Its Physiological Consequences, Jiajing Xu Dec 2018

Kcnq1/Kcne1 Interaction In The Cardiac Iks Channel And Its Physiological Consequences, Jiajing Xu

Engineering and Applied Science Theses & Dissertations

Dynamic conformational changes of ion channel proteins during activation gating determine their function as carriers of current. The relationship between these molecular movements and channel function over the physiological timescale of the action potential (AP) has not been fully established due to limitations of existing techniques. We constructed a library of possible cardiac IKs protein conformations and applied a combination of protein segmentation and energy linearization to study this relationship computationally. Simulations reproduced the effects of the beta-subunit (KCNE1) on the alpha-subunit (KCNQ1) dynamics and function, observed in experiments. Mechanistically, KCNE1 increased the probability of “visiting” conducting pore conformations on ...


Radiolabeled Nanohydroxyapatite As A Platform For The Development Of New Pet Imaging Agents, Stacy Lee Queern Dec 2018

Radiolabeled Nanohydroxyapatite As A Platform For The Development Of New Pet Imaging Agents, Stacy Lee Queern

Arts & Sciences Electronic Theses and Dissertations

Positron emission tomography (PET) imaging utilizes drugs labeled with positron emitters to target and evaluate different biological processes occurring in the body. Tailoring medicine to the individual allows for higher quality of care with better diagnosis and treatment and is a key purpose for advancing research into developing new platforms for PET imaging agents. A PET nuclide of high interest for the development of these agents is 89Zr. This can be attributed to the long half-life of 3.27 days and low positron energy of 89Zr.

In this work, we developed a production method for 89Zr using Y sputtered coins ...


Assessing Biofiltration Without Ozonation For Removal Of Trihalomethane Precursors In Drinking Water At The Beaver Water District Drinking Water Treatment Plant, Sana Ajaz Dec 2018

Assessing Biofiltration Without Ozonation For Removal Of Trihalomethane Precursors In Drinking Water At The Beaver Water District Drinking Water Treatment Plant, Sana Ajaz

Theses and Dissertations

Biofiltration without pre-ozonation has the capability to remove natural organic matter (NOM) fractions that serve as precursors of disinfection byproducts (DBPs), which include the four regulated trihalomethanes (THMs) and dichloroacetonitrile (DCAN). Rapid small-scale column tests (RSSCTs) and Pilot Plant filters operated at empty-bed contact times (EBCTs) of 4, 8, and 16 minutes were used to evaluate the performance of nutrient-amended (free ammonia and phosphorus) biofiltration for THM and DCAN precursor removal, as measured using formation potential (FP) tests. NOM surrogates – which include dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA254) and fluorescence-PARAFAC components – were measured weekly throughout the 30-week study ...


Modulating Viscoelasticity, Stiffness, And Degradation Of Synthetic Cellular Niches Via Stoichiometric Tuning Of Covalent Versus Dynamic Noncovalent Cross-Linking, Yu Tan, Henry Huang, David C. Ayers, Jie Song Aug 2018

Modulating Viscoelasticity, Stiffness, And Degradation Of Synthetic Cellular Niches Via Stoichiometric Tuning Of Covalent Versus Dynamic Noncovalent Cross-Linking, Yu Tan, Henry Huang, David C. Ayers, Jie Song

Open Access Articles

Viscoelasticity, stiffness, and degradation of tissue matrices regulate cell behavior, yet predictive synergistic tuning of these properties in synthetic cellular niches remains elusive. We hypothesize that reversible physical cross-linking can be quantitatively introduced to synthetic hydrogels to accelerate stress relaxation and enhance network stiffness, while strategic placement of isolated labile linkages near cross-linking sites can predict hydrogel degradation, both of which are essential for creating adaptive cellular niches. To test these hypotheses, chondrocytes were encapsulated in hydrogels formed by biorthogonal covalent and noncovalent physical cross-linking of a pair of hydrophilic building blocks. The stiffer and more viscoelastic hydrogels with DBCO-DBCO ...


Piezoresponse, Mechanical, And Electrical Characteristics Of Synthetic Spider Silk Nanofibers, Nader Shehata, Ishac Kandas, Ibrahim Hassounah, Patrik Sobolčiak, Igor Krupa, Miroslav Mrlik, Anton Popelka, Jesse Steadman, Randolph V. Lewis Aug 2018

Piezoresponse, Mechanical, And Electrical Characteristics Of Synthetic Spider Silk Nanofibers, Nader Shehata, Ishac Kandas, Ibrahim Hassounah, Patrik Sobolčiak, Igor Krupa, Miroslav Mrlik, Anton Popelka, Jesse Steadman, Randolph V. Lewis

Biology Faculty Publications

This work presents electrospun nanofibers from synthetic spider silk protein, and their application as both a mechanical vibration and humidity sensor. Spider silk solution was synthesized from minor ampullate silk protein (MaSp) and then electrospun into nanofibers with a mean diameter of less than 100 nm. Then, mechanical vibrations were detected through piezoelectric characteristics analysis using a piezo force microscope and a dynamic mechanical analyzer with a voltage probe. The piezoelectric coefficient (d33) was determined to be 3.62 pC/N. During humidity sensing, both mechanical and electric resistance properties of spider silk nanofibers were evaluated at varying high-level ...


A Photoactivatable Bodipy Probe For Localization‐Based Super‐Resolution Cellular Imaging, Chamari S. Wijesooriya, Julie A. Peterson, Pradeep Shrestha, Elizabeth J. Gehrmann, Arthur H. Winter, Emily Smith Jul 2018

A Photoactivatable Bodipy Probe For Localization‐Based Super‐Resolution Cellular Imaging, Chamari S. Wijesooriya, Julie A. Peterson, Pradeep Shrestha, Elizabeth J. Gehrmann, Arthur H. Winter, Emily Smith

Ames Laboratory Accepted Manuscripts

The synthesis and application of a photoactivatable boron‐alkylated BODIPY probe for localization‐based super‐resolution microscopy is reported. Photoactivation and excitation of the probe is achieved by a previously‐unknown boron‐photodealkylation reaction with a single low‐power visible laser and without requiring the addition of reducing agents or oxygen scavengers in the imaging buffer. These features lead to a versatile probe for localization‐based microscopy of biological systems. The probe can be easily linked to nucleophile‐containing molecules to target specific cellular organelles. By attaching paclitaxel to the photoactivatable BODIPY, in vitro and in vivo super‐resolution imaging ...


Polymeric Peptide Mimics For Protein Delivery, Coralie Backlund Jul 2018

Polymeric Peptide Mimics For Protein Delivery, Coralie Backlund

Doctoral Dissertations

The plasma membrane is a major obstacle in the development and use of biomacromolecules for intracellular applications. Consequently, proteins with intracellular targets represent an enormous, yet under studied avenue for therapeutics. Extended research has aimed at facilitating intracellular delivery of exogenous proteins using protein transduction domains (PTDs), which allow transport of bioactive molecules into cells. Synthetic polymers, inspired by PTDs, provide a well-controlled platform to vary molecular architecture for structure activity relationship studies. Specifically, this thesis focuses on the use of ring-opening metathesis, a facile and efficient polymerization technique, through which we can vary structural parameters to optimize delivery of ...


Super‐Resolution Imaging Of Amyloid Structures Over Extended Times By Using Transient Binding Of Single Thioflavin T Molecules, Kevin Spehar, Tianben Ding, Yuanzi Sun, Niraja Kedia, Jin Lu, George R. Nahass, Matthew D. Lew, Jan Bieschke Jun 2018

Super‐Resolution Imaging Of Amyloid Structures Over Extended Times By Using Transient Binding Of Single Thioflavin T Molecules, Kevin Spehar, Tianben Ding, Yuanzi Sun, Niraja Kedia, Jin Lu, George R. Nahass, Matthew D. Lew, Jan Bieschke

Electrical & Systems Engineering Publications and Presentations

Oligomeric amyloid structures are crucial therapeutic targets in Alzheimer's and other amyloid diseases. However, these oligomers are too small to be resolved by standard light microscopy. We have developed a simple and versatile tool to image amyloid structures by using thioflavin T without the need for covalent labeling or immunostaining. The dynamic binding of single dye molecules generates photon bursts that are used for fluorophore localization on a nanometer scale. Thus, photobleaching cannot degrade image quality, allowing for extended observation times. Super‐resolution transient amyloid binding microscopy promises to directly image native amyloid by using standard probes and record ...


Preparation Of Supramolecular Amphiphilic Cyclodextrin Bilayer Vesicles For Pharmaceutical Applications, Kate E. Frischkorn Jun 2018

Preparation Of Supramolecular Amphiphilic Cyclodextrin Bilayer Vesicles For Pharmaceutical Applications, Kate E. Frischkorn

Master's Theses

Recent pharmaceutical developments have investigated using supramolecular nanoparticles in order to increase the bioavailability and solubility of drugs delivered in various methods. Modification of the carbohydrate cyclodextrin increases the ability to encapsulate hydrophobic pharmaceutical molecules by forming a carrier with a hydrophobic core and hydrophilic exterior. Guest molecules are commonly added to these inclusion complexes in order to add stability and further increase targeting abilities of the carriers. One such guest molecule is adamantine combined with a poly(ethylene glycol) chain. Vesicles are formed by hydrating a thin film of amphiphilic cyclodextrin and guest molecules in buffer solution that mimics ...


Controlled Positioning Of Microbubbles And Induced Cavitation Using A Dual-Frequency Transducer And Microfiber Adhesion Techniques, Alex H. Wrede, Aarthy Shah, Marilyn C. Mcnamara, Reza Montazami, Nicole N. Hashemi May 2018

Controlled Positioning Of Microbubbles And Induced Cavitation Using A Dual-Frequency Transducer And Microfiber Adhesion Techniques, Alex H. Wrede, Aarthy Shah, Marilyn C. Mcnamara, Reza Montazami, Nicole N. Hashemi

Mechanical Engineering Publications

We report a study on two methods that enable spatial control and induced cavitation on targeted microbubbles (MBs). Cavitation is known to be present in many situations throughout nature. This phenomena has been proven to have the energy to erode alloys, like steel, in propellers and turbines. It is recently theorized that cavitation occurs inside the skull during a traumatic-brain injury (TBI) situation. Controlled cavitation methods could help better understand TBIs and explain how neurons respond at moments of trauma. Both of our approaches involve an ultrasonic transducer and bio-compatible Polycaprolactone (PCL) microfibers. These methods are reproducible as well as ...


Elastin-Like Polypeptide Fusion Tag As A Protein-Dependent Solubility Enhancer Of Cysteine-Knot Growth Factors, Tamina L. Johnson Apr 2018

Elastin-Like Polypeptide Fusion Tag As A Protein-Dependent Solubility Enhancer Of Cysteine-Knot Growth Factors, Tamina L. Johnson

Graduate Theses and Dissertations

Elastin-like peptide (ELP) fusions promote therapeutic delivery and efficacy. Recombinant proteins, like neurotrophins, lack bioavailability, have short in vivo half-lives, and require high manufacturing costs. Fusing recombinant proteins with genetically encodable ELPs will increase bioavailability, enhance in vivo solubilization, as well as provide a cost-effective method for purification without the need for chromatography. During expression of neurotrophin-ELP (N-ELP) fusions, dense water-insoluble aggregates known as inclusion bodies (IBs) are formed. Inclusion bodies are partially and misfolded proteins that usually require denaturants like Urea for solubilization. Strong denaturants arrest ELPs stimuli-responsive property and increase unwanted aggregation, making purification difficult, yet possible. The ...


Metabolism-Driven High-Throughput Cancer Identification With Glut5-Specific Molecular Probes, Srinivas Kannan, Vagarshak Begoyan, Joseph Fedie, Shuai Xia, Łukasz J. Weseliński, Marina Tanasova, Smitha Rao Apr 2018

Metabolism-Driven High-Throughput Cancer Identification With Glut5-Specific Molecular Probes, Srinivas Kannan, Vagarshak Begoyan, Joseph Fedie, Shuai Xia, Łukasz J. Weseliński, Marina Tanasova, Smitha Rao

Michigan Tech Publications

Point-of-care applications rely on biomedical sensors to enable rapid detection with high sensitivity and selectivity. Despite advances in sensor development, there are challenges in cancer diagnostics. Detection of biomarkers, cell receptors, circulating tumor cells, gene identification, and fluorescent tagging are time-consuming due to the sample preparation and response time involved. Here, we present a novel approach to target the enhanced metabolism in breast cancers for rapid detection using fluorescent imaging. Fluorescent analogs of fructose target the fructose-specific transporter GLUT5 in breast cancers and have limited to no response from normal cells. These analogs demonstrate a marked difference in adenocarcinoma and ...


Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein, Pegah Kord Forooshani, Bruce P. Lee Mar 2018

Recent Approaches In Designing Bioadhesive Materials Inspired By Mussel Adhesive Protein, Pegah Kord Forooshani, Bruce P. Lee

Bruce Lee

Marine mussels secret protein-based adhesives, which enable them to anchor to various surfaces in a saline, intertidal zone. Mussel foot proteins (Mfps) contain a large abundance of a unique, catecholic amino acid, Dopa, in their protein sequences. Catechol offers robust and durable adhe-sion to various substrate surfaces and contributes to the curing of the adhesive plaques. In this article, we review the unique features and the key functionalities of Mfps, catechol chemistry, and strategies for preparing catechol-functionalized poly- mers. Specifically, we reviewed recent findings on the contributions of various features of Mfps on interfacial binding, which include coacervate formation, surface ...


Enhanced Hot Electron Lifetimes In Quantum Wells With Inhibited Phonon Coupling, Hamidreza Esmaielpour, Vincent R. Whiteside, Herath P. Piyathilaka, Sangeetha Vijeyaragunathan, Bin Wang, Echo Adcock-Smith, Kenneth P. Roberts, Tetsuya D. Mishima, Michael B. Santos, Alan D. Bristow, Ian R. Sellers Jan 2018

Enhanced Hot Electron Lifetimes In Quantum Wells With Inhibited Phonon Coupling, Hamidreza Esmaielpour, Vincent R. Whiteside, Herath P. Piyathilaka, Sangeetha Vijeyaragunathan, Bin Wang, Echo Adcock-Smith, Kenneth P. Roberts, Tetsuya D. Mishima, Michael B. Santos, Alan D. Bristow, Ian R. Sellers

Faculty & Staff Scholarship

Hot electrons established by the absorption of high-energy photons typically thermalize on a picosecond time scale in a semiconductor, dissipating energy via various phonon-mediated relaxation pathways. Here it is shown that a strong hot carrier distribution can be produced using a type-II quantum well structure. In such systems it is shown that the dominant hot carrier thermalization process is limited by the radiative recombination lifetime of electrons with reduced wavefunction overlap with holes. It is proposed that the subsequent reabsorption of acoustic and optical phonons is facilitated by a mismatch in phonon dispersions at the InAs-AlAsSb interface and serves to ...


Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed Dec 2017

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of ...


Design And Synthesis Of Analogs Of Myo-Inositol, Serine, And Cysteine To Enable Chemical Biology Studies, Tanei J. Ricks Dec 2017

Design And Synthesis Of Analogs Of Myo-Inositol, Serine, And Cysteine To Enable Chemical Biology Studies, Tanei J. Ricks

Doctoral Dissertations

Phosphorylated myo-inositol compounds including inositol phosphates (InsPs) as well as the phosphatidylinositol polyphosphate lipids (PIPns) are critical biomolecules that regulate many of the most important biological processes and pathways. They are aberrant in many disease states due to their regulatory function. The same is true of the phospholipid phosphatidylserine (PS) which can serve as a marker to begin apoptosis. However, the full scope of activities of these structures is not clear, particularly since techniques that enable global detection and analysis of the production of these compounds spatially and temporally are lacking. With all of these obstacles in ...


Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel Nov 2017

Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel

Doctoral Dissertations

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic ...


Protein-Nanoparticle Co-Engineering: Self-Assembly, Intracellular Protein Delivery, And Crispr/Cas9-Based Gene Editing, Rubul Mout Nov 2017

Protein-Nanoparticle Co-Engineering: Self-Assembly, Intracellular Protein Delivery, And Crispr/Cas9-Based Gene Editing, Rubul Mout

Doctoral Dissertations

Direct cytoplasmic delivery of gene editing nucleases such CRISPR/Cas9 systems and therapeutic proteins provides enormous opportunities in curing human genetic diseases, and assist research in basic cell biology. One approach to attain such a goal is through engineering nanotechnological tools to mimic naturally existing intra- and extracellular protein delivery/transport systems. Nature builds transport systems for proteins and other biomolecules through evolution-derived sophisticated molecular engineering. Inspired by such natural assemblies, I employed molecular engineering approaches to fabricate self-assembled nanostructures to use as intracellular protein delivery tools. Briefly, proteins and gold nanoparticles were co-engineered to carry complementary electrostatic recognition elements ...


How Strongly Do Oysters Stick?, Nicolás M. Morato, Andrés M. Tibabuzo, Jonathan J. Wilker Aug 2017

How Strongly Do Oysters Stick?, Nicolás M. Morato, Andrés M. Tibabuzo, Jonathan J. Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Biological adhesives are a type of interfacial material that has incredible potential to generate new biomimetic compounds that can replace current strong, but toxic, adhesives. Therefore, a study of the chemical composition and mechanical properties of those bio-adhesives is necessary. However, in the case of oysters, despite known chemical characterization of the adult’s adhesive, there are almost no studies on its mechanical properties. Furthermore, there is no available information on the adhesive properties of spat (oysters in their larvae state). Herein, we present the first mechanical characterization of the spat adhesive, measuring its adhesion strength by hydrodynamic determination using ...


Chelator-Free Radiolabeling Of Serrs Nanoparticles For Whole-Body Pet And Intraoperative Raman Imaging, Matthew A. Wall, Travis Shaffer, Stefan Harmsen, Darjus-Felix Tschaharganeh, Chun-Hao Huang, Scott W. Lowe, Charles Michael Drain, Moritz F. Kircher Jul 2017

Chelator-Free Radiolabeling Of Serrs Nanoparticles For Whole-Body Pet And Intraoperative Raman Imaging, Matthew A. Wall, Travis Shaffer, Stefan Harmsen, Darjus-Felix Tschaharganeh, Chun-Hao Huang, Scott W. Lowe, Charles Michael Drain, Moritz F. Kircher

Publications and Research

A single contrast agent that offers whole-body non-invasive imaging along with the superior sensitivity and spatial resolution of surface-enhanced resonance Raman scattering (SERRS) imaging would allow both pre-operative mapping and intraoperative imaging and thus be highly desirable. We hypothesized that labeling our recently reported ultrabright SERRS nanoparticles with a suitable radiotracer would enable pre-operative identification of regions of interest with whole body imaging that can be rapidly corroborated with a Raman imaging device or handheld Raman scanner in order to provide high precision guidance during surgical procedures. Here we present a straightforward new method that produces radiolabeled SERRS nanoparticles for ...


Understanding The Surface Fouling Mechanism Of Ultrananocrystalline Diamond Microelectrodes Using Microfluidics For Neurochemical Detection, An-Yi Chang Jul 2017

Understanding The Surface Fouling Mechanism Of Ultrananocrystalline Diamond Microelectrodes Using Microfluidics For Neurochemical Detection, An-Yi Chang

Doctoral Dissertations

Electrochemical methods are widely used for chronic neurochemical sensing, but thus far, the organic solution redox reactions fouled the electrodes' surface. It caused the reduction of sensitivity and the electrodes' lifetime.

Here, we present the boron-doped nanocrystalline diamond microelectrodes (BDUNCD) as the next generation electrode material for neurochemical sensor development. To aid in long-term chronic monitoring of neurochemicals, they have a wide window of electrochemical potential, extremely low background current, and excellent chemical inertness. The main research goal is to reduce the rate of electrode fouling due to the reaction by-products, and significantly extend their useful lifetime.

We systematically characterize ...