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Full-Text Articles in Biomedical Engineering and Bioengineering

Transfer Of Assembled Collagen Fibrils To Flexible Substrates For Mechanically Tunable Contact Guidance Cues, Juan Wang, Joseph Koelbl, Anuraag Boddupalli, Zhiqi Yao, Kaitlin M. Bratlie, Ian C. Schneider Oct 2018

Transfer Of Assembled Collagen Fibrils To Flexible Substrates For Mechanically Tunable Contact Guidance Cues, Juan Wang, Joseph Koelbl, Anuraag Boddupalli, Zhiqi Yao, Kaitlin M. Bratlie, Ian C. Schneider

Chemical and Biological Engineering Publications

Contact guidance or bidirectional migration along aligned fibers modulates many physiological and pathological processes such as wound healing and cancer invasion. Aligned 2D collagen fibrils epitaxially grown on mica substrates replicate many features of contact guidance seen in aligned 3D collagen fiber networks. However, these 2D collagen self-assembled substrates are difficult to image through, do not have known or tunable mechanical properties and cells degrade and mechanically detach collagen fibrils from the surface, leading to an inability to assess contact guidance over long times. Here, we describe the transfer of aligned collagen fibrils from mica substrates to three different functionalized ...


Escherichia Coli Attachment To Model Particulates: The Effects Of Bacterial Cell Characteristics And Particulate Properties, Xiao Liang, Chunyu Liao, Michelle L. Soupir, Laura R. Jarboe, Michael L. Thompson, Philip M. Dixon Sep 2017

Escherichia Coli Attachment To Model Particulates: The Effects Of Bacterial Cell Characteristics And Particulate Properties, Xiao Liang, Chunyu Liao, Michelle L. Soupir, Laura R. Jarboe, Michael L. Thompson, Philip M. Dixon

Chemical and Biological Engineering Publications

E. coli bacteria move in streams freely in a planktonic state or attached to suspended particulates. Attachment is a dynamic process, and the fraction of attached microorganisms is thought to be affected by both bacterial characteristics and particulate properties. In this study, we investigated how the properties of cell surfaces and stream particulates influence attachment. Attachment assays were conducted for 77 E. coli strains and three model particulates (ferrihydrite, Ca-montmorillonite, or corn stover) under environmentally relevant conditions. Surface area, particle size distribution, and total carbon content were determined for each type of particulate. Among the three particulates, attachment fractions to ...


Hemolysis As A Rapid Screening Technique For Assessing The Toxicity Of Native Surfactin And A Genetically Engineered Derivative, William J. Colonna, Mustafa E. Marti, John A. Nyman, Chris Green, Charles Glatz Mar 2017

Hemolysis As A Rapid Screening Technique For Assessing The Toxicity Of Native Surfactin And A Genetically Engineered Derivative, William J. Colonna, Mustafa E. Marti, John A. Nyman, Chris Green, Charles Glatz

Chemical and Biological Engineering Publications

If biosurfactants are to achieve their promise in environmental oil-spill remediation, their toxicity to marine life must be assessed. A killifish larvae assay is commonly used as a measure of toxicity but is difficult and nonlinear in response. Red blood cell (RBC) hemolysis has also been the basis for assays of some surfactant levels. Here we present a modified sheep RBC suspension assay and compare its response to that of the fish assay for surfactin and its genetically modified variant fatty-acyl-glutamate (FA-Glu). This is the first report of hemolytic activity as a property of FA-Glu. The method's potential for ...


Myosin Phosphorylation On Stress Fibers Predicts Contact Guidance Behavior Across Diverse Breast Cancer Cells, Juan Wang, Ian C. Schneider Mar 2017

Myosin Phosphorylation On Stress Fibers Predicts Contact Guidance Behavior Across Diverse Breast Cancer Cells, Juan Wang, Ian C. Schneider

Chemical and Biological Engineering Publications

During cancer progression the extracellular matrix is remodeled, forming aligned collagen fibers that proceed radially from the tumor, resulting in invasion. We have recently shown that different invasive breast cancer cells respond to epitaxially grown, aligned collagen fibrils differently. This article develops insight into why these cells differ in their contact guidance fidelity. Small changes in contractility or adhesion dramatically alter directional persistence on aligned collagen fibrils, while migration speed remains constant. The directionality of highly contractile and adhesive MDA-MB-231 cells can be diminished by inhibiting Rho kinase or β1 integrin binding. Inversely, the directionality of less contractile and adhesive ...


Improving Escherichia Coli Membrane Integrity And Fatty Acid Production By Expression Tuning Of Fadl And Ompf, Zaigao Tan, William Black, Jong Moon Yoon, Jacqueline V. Shanks, Laura R. Jarboe Feb 2017

Improving Escherichia Coli Membrane Integrity And Fatty Acid Production By Expression Tuning Of Fadl And Ompf, Zaigao Tan, William Black, Jong Moon Yoon, Jacqueline V. Shanks, Laura R. Jarboe

Chemical and Biological Engineering Publications

Background

Construction of microbial biocatalysts for the production of biorenewables at economically viable yields and titers is frequently hampered by product toxicity. Membrane damage is often deemed as the principal mechanism of this toxicity, particularly in regards to decreased membrane integrity. Previous studies have attempted to engineer the membrane with the goal of increasing membrane integrity. However, most of these works focused on engineering of phospholipids and efforts to identify membrane proteins that can be targeted to improve fatty acid production have been unsuccessful.

Results

Here we show that deletion of outer membrane protein ompF significantly increased membrane integrity, fatty ...


Smart Materials For Nerve Regeneration And Neural Tissue Engineering, Surya K. Mallapragada, Metin Uz Jan 2017

Smart Materials For Nerve Regeneration And Neural Tissue Engineering, Surya K. Mallapragada, Metin Uz

Chemical and Biological Engineering Publications

Stimuli-responsive smart-biomaterial-based approaches have been identified as a promising tool for nerve regeneration and neural tissue engineering. Understanding the stimuli-responsive behavior of the smart materials, along with the fundamentals of cellular interactions, is the key to future strategies for neural tissue engineering. Advances in the development and application of smart biomaterials and 3-D scaffold fabrication techniques as well as cellular reprogramming and transdifferentiation technologies make it possible to combine stem cells, cellular engineering, drug/gene delivery systems, nanotechnology and biomaterial-based therapies to develop experimental and clinical strategies for neural tissue engineering. The application of smart biomaterials in these technologies is ...


Recovery And Utilization Of Lignin Monomers As Part Of The Biorefinery Approach, Kirsten M. Davis, Marjorie Rover, Robert C. Brown, Xianglan Bai, Zhiyou Wen, Laura R. Jarboe Oct 2016

Recovery And Utilization Of Lignin Monomers As Part Of The Biorefinery Approach, Kirsten M. Davis, Marjorie Rover, Robert C. Brown, Xianglan Bai, Zhiyou Wen, Laura R. Jarboe

Chemical and Biological Engineering Publications

Lignin is a substantial component of lignocellulosic biomass but is under-utilized relative to the cellulose and hemicellulose components. Historically, lignin has been burned as a source of process heat, but this heat is usually in excess of the process energy demands. Current models indicate that development of an economically competitive biorefinery system requires adding value to lignin beyond process heat. This addition of value, also known as lignin valorization, requires economically viable processes for separating the lignin from the other biomass components, depolymerizing the lignin into monomeric subunits, and then upgrading these monomers to a value-added product. The fact that ...


Accounting For Host Cell Protein Behavior In Anion-Exchange Chromatography, Ryan K. Swanson, Ruo Xu, Daniel S. Nettleton, Charles Glatz Jan 2016

Accounting For Host Cell Protein Behavior In Anion-Exchange Chromatography, Ryan K. Swanson, Ruo Xu, Daniel S. Nettleton, Charles Glatz

Chemical and Biological Engineering Publications

Host cell proteins (HCP) are a problematic set of impurities in downstream processing (DSP) as they behave most similarly to the target protein during separation. Approaching DSP with the knowledge of HCP separation behavior would be beneficial for the production of high purity recombinant biologics. Therefore, this work was aimed at characterizing the separation behavior of complex mixtures of HCP during a commonly used method: anion-exchange chromatography (AEX). An additional goal was to evaluate the performance of a statistical methodology, based on the characterization data, as a tool for predicting protein separation behavior. Aqueous two-phase partitioning followed by two-dimensional electrophoresis ...


Epitaxially Grown Collagen Fibrils Reveal Diversity In Contact Guidance Behavior Among Cancer Cells, Juan Wang, Joseph W. Petefish, Andrew C. Hillier, Ian C. Schneider Jan 2015

Epitaxially Grown Collagen Fibrils Reveal Diversity In Contact Guidance Behavior Among Cancer Cells, Juan Wang, Joseph W. Petefish, Andrew C. Hillier, Ian C. Schneider

Chemical and Biological Engineering Publications

Invasion of cancer cells into the surrounding tissue is an important step during cancer progression and is driven by cell migration. Cell migration can be random, but often it is directed by various cues such as aligned fibers composed of extracellular matrix (ECM), a process called contact guidance. During contact guidance, aligned fibers bias migration along the long axis of the fibers. These aligned fibers of ECM are commonly composed of type I collagen, an abundant structural protein around tumors. In this paper, we epitaxially grew several different patterns of organized type I collagen on mica and compared the morphology ...


Hemagglutinin-Based Polyanhydride Nanovaccines Against H5n1 Influenza Elicit Protective Virus Neutralizing Titers And Cell-Mediated Immunity, Kathleen Alaine Ross, Hyelee Park Loyd, Wuwei Wu, Lucas Mark Huntimer, Shaheen Ahmed, Anthony Sambol, Scott Broderick, Zachary Flickinger, Krishna Rajan, Tatiana Bronich, Surya K. Mallapragada, Michael J. Wannemuehler, Susan Long Carpenter, Balaji Narasimhan Jan 2015

Hemagglutinin-Based Polyanhydride Nanovaccines Against H5n1 Influenza Elicit Protective Virus Neutralizing Titers And Cell-Mediated Immunity, Kathleen Alaine Ross, Hyelee Park Loyd, Wuwei Wu, Lucas Mark Huntimer, Shaheen Ahmed, Anthony Sambol, Scott Broderick, Zachary Flickinger, Krishna Rajan, Tatiana Bronich, Surya K. Mallapragada, Michael J. Wannemuehler, Susan Long Carpenter, Balaji Narasimhan

Chemical and Biological Engineering Publications

H5N1 avian influenza is a significant global concern with the potential to become the next pandemic threat. Recombinant subunit vaccines are an attractive alternative for pandemic vaccines compared to traditional vaccine technologies. In particular, polyanhydride nanoparticles encapsulating subunit proteins have been shown to enhance humoral and cell-mediated immunity and provide protection upon lethal challenge. In this work, a recombinant H5 hemagglutinin trimer (H53) was produced and encapsulated into polyanhydride nanoparticles. The studies performed indicated that the recombinant H53 antigen was a robust immunogen. Immunizing mice with H53 encapsulated into polyanhydride nanoparticles induced high neutralizing antibody titers and enhanced CD4+ T ...


Responsive Pentablock Copolymers For Sirna Delivery, Surya K. Mallapragada, Metin Uz, Sacide Alsoy Altinkaya Jan 2015

Responsive Pentablock Copolymers For Sirna Delivery, Surya K. Mallapragada, Metin Uz, Sacide Alsoy Altinkaya

Chemical and Biological Engineering Publications

In this study, temperature and pH responsive cationic and amphiphilic pentablock copolymers, which consist of the temperature responsive triblock Pluronic F127 sandwiched between pH responsive PDEAEM (poly(2-diethylaminoethyl methacrylate)) end blocks, were used for the first time in the development of polyplex and gold nanoparticle (AuNP) based multicomponent siRNA delivery systems (MCSs). Copolymers in both systems protected siRNA from external effects, provided cell entry and endosomal escape. The thermoreversible micellization of the hydrophobic PPO block facilitated the cellular entry while the PDEAEM blocks enhanced the endosomal escape through protonated tertiary amine groups by pH buffering. The synergistic advantages of the ...


Cellular Contractility And Extracellular Matrix Stiffness Regulate Matrix Metalloproteinase Activity In Pancreatic Cancer Cells, Amanda Haage, Ian C. Schneider Aug 2014

Cellular Contractility And Extracellular Matrix Stiffness Regulate Matrix Metalloproteinase Activity In Pancreatic Cancer Cells, Amanda Haage, Ian C. Schneider

Chemical and Biological Engineering Publications

The pathogenesis of cancer is often driven by local invasion and metastasis. Recently, mechanical properties of the tumor microenvironment have been identified as potent regulators of invasion and metastasis, while matrix metalloproteinases (MMPs) are classically known as significant enhancers of cancer cell migration and invasion. Here we have been able to sensitively measure MMP activity changes in response to specific extracellular matrix (ECM) environments and cell contractility states. A pancreatic cancer cell line, Panc-1 cells, up-regulate MMP activities between 3- and 10- fold with increased cell contractility. Conversely, they down-regulate MMP activities when contractility is blocked to levels seen with ...


Characterization Of Sheared Colloidal Aggregation Using Langevin Dynamics Simulation, Sergiy Markutsya, Rodney O. Fox, Shankar Subramaniam Jun 2014

Characterization Of Sheared Colloidal Aggregation Using Langevin Dynamics Simulation, Sergiy Markutsya, Rodney O. Fox, Shankar Subramaniam

Chemical and Biological Engineering Publications

Aggregation of colloidal particles under shear is studied in model systems using a Langevin dynamics model with an improved interparticle interaction potential. In the absence of shear, aggregates that form are characterized by compact structure at small scales and ramified structure at larger scales. This confirms the structural crossover mechanism previously suggested by Sorensen and coworkers, that colloidal aggregation occurs due to monomer addition at small scales and due to cluster-cluster aggregation at large scales. The fractal dimension of nonsheared aggregates is scale-dependent. Smaller aggregates have a higher fractal dimension than larger ones, but the radius of gyration where this ...


The Number Of Lines A Cell Contacts And Cell Contractility Drive The Efficiency Of Contact Guidance, Nicholas R. Romsey, Yue Hou, Laura L. Rodriguez, Ian C. Schneider Mar 2014

The Number Of Lines A Cell Contacts And Cell Contractility Drive The Efficiency Of Contact Guidance, Nicholas R. Romsey, Yue Hou, Laura L. Rodriguez, Ian C. Schneider

Chemical and Biological Engineering Publications

Cell migration is an important biological function that impacts many physiological and pathological processes. Often migration is directed along various densities of aligned fibers of collagen, a process called contact guidance. However, cells adhere to other components in the extracellular matrix, possibly affecting migrational behavior. Additionally, changes in intracellular contractility are well known to affect random migration, but its effect on contact guidance is less known. This study examines differences in directed migration in response to variations in the spacing of collagen, non-specific background adhesion strength and myosin II-mediated contractility. Collagen was microcontact printed onto glass substrates and timelapse live-cell ...


Angle-Tunable Enhanced Infrared Reflection Absorption Spectroscopy Via Grating-Coupled Surface Plasmon Resonance, Joseph W. Petefish, Andrew C. Hillier Jan 2014

Angle-Tunable Enhanced Infrared Reflection Absorption Spectroscopy Via Grating-Coupled Surface Plasmon Resonance, Joseph W. Petefish, Andrew C. Hillier

Chemical and Biological Engineering Publications

Surface enhanced infrared absorption (SEIRA) spectroscopy is an attractive method for increasing the prominence of vibrational modes in infrared spectroscopy. To date, the majority of reports associated with SEIRA utilize localized surface plasmon resonance from metal nanoparticles to enhance electromagnetic fields in the region of analytes. Limited work has been performed using propagating surface plasmons as a method for SEIRA excitation. In this report, we demonstrate angle-tunable enhancement of vibrational stretching modes associated with a thin poly(methyl methacrylate) (PMMA) film that is coupled to a silver-coated diffraction grating. Gratings are fabricated using laser interference lithography to achieve precise surface ...


Collagen Attachment To The Substrate Controls Cell Clustering Through Migration, Yue Hou, Laura L. Rodriguez, Juan Wang, Ian C. Schneider Jan 2014

Collagen Attachment To The Substrate Controls Cell Clustering Through Migration, Yue Hou, Laura L. Rodriguez, Juan Wang, Ian C. Schneider

Chemical and Biological Engineering Publications

Cell clustering and scattering play important roles in cancer progression and tissue engineering. While the extracellular matrix (ECM) is known to control cell clustering, much of the quantitative work has focused on the analysis of clustering between cells with strong cell-cell junctions. Much less is known about how the ECM regulates cells with weak cell-cell contact. Clustering characteristics were quantified in rat adenocarcinoma cells, which form clusters on physically adsorbed collagen substrates, but not on covalently attached collagen substrates. Covalently attaching collagen inhibited desorption of collagen from the surface. While changes in proliferation rate could not explain differences seen in ...


Nucleation Of Iron Oxide Nanoparticles Mediated By Mms6 Protein In Situ, Sanjay Kashyap, Taylor J. Woehl, Xunpei Liu, Surya K. Mallapragada, Tanya Prozorov Jan 2014

Nucleation Of Iron Oxide Nanoparticles Mediated By Mms6 Protein In Situ, Sanjay Kashyap, Taylor J. Woehl, Xunpei Liu, Surya K. Mallapragada, Tanya Prozorov

Chemical and Biological Engineering Publications

Biomineralization proteins are widely used as templating agents in biomimetic synthesis of a variety of organic-inorganic nanostructures. However, the role of the protein in controlling the nucleation and growth of biomimetic particles is not well understood, because the mechanism of the bioinspired reaction is often deduced from ex situ analysis of the resultant nanoscale mineral phase. Here we report the direct visualization of biomimetic iron oxide nanoparticle nucleation mediated by an acidic bacterial recombinant protein, Mms6, during an in situ reaction induced by the controlled addition of sodium hydroxide to solution-phase Mms6 protein micelles incubated with ferric chloride. Using in ...


A Systems Approach To Designing Next Generation Vaccines: Combining α-Galactose Modified Antigens With Nanoparticle Platforms, Yashdeep Phanse, Brenda Rocio Carrillo-Conde, Amanda Ellen Ramer-Tait, Scott Broderick, Chang Sun Kong, Krishna Rajan, Ramon Flick, Robert B. Mandell, Balaji Narasimhan, Michael J. Wannemuehler Jan 2014

A Systems Approach To Designing Next Generation Vaccines: Combining α-Galactose Modified Antigens With Nanoparticle Platforms, Yashdeep Phanse, Brenda Rocio Carrillo-Conde, Amanda Ellen Ramer-Tait, Scott Broderick, Chang Sun Kong, Krishna Rajan, Ramon Flick, Robert B. Mandell, Balaji Narasimhan, Michael J. Wannemuehler

Chemical and Biological Engineering Publications

Innovative vaccine platforms are needed to develop effective countermeasures against emerging and re-emerging diseases. These platforms should direct antigen internalization by antigen presenting cells and promote immunogenic responses. This work describes an innovative systems approach combining two novel platforms, αGalactose (αGal)-modification of antigens and amphiphilic polyanhydride nanoparticles as vaccine delivery vehicles, to rationally design vaccine formulations. Regimens comprising soluble αGal-modified antigen and nanoparticle-encapsulated unmodified antigen induced a high titer, high avidity antibody response with broader epitope recognition of antigenic peptides than other regimen. Proliferation of antigen-specific CD4 + T cells was also enhanced compared to a traditional ...


Development Of A Combined Catalyst And Sorbent For The Water Gas Shift Reaction, Meng Kong, Karl O. Albrecht, Brent H. Shanks, Thomas D. Wheelock Jan 2014

Development Of A Combined Catalyst And Sorbent For The Water Gas Shift Reaction, Meng Kong, Karl O. Albrecht, Brent H. Shanks, Thomas D. Wheelock

Chemical and Biological Engineering Publications

A combined catalyst and sorbent was developed for reacting CO with steam to produce H2 in a single reaction stage at 600 °C by employing the water gas shift (WGS) reaction. The combined material was in the form of spherical pellets where each pellet consisted of a CaO core for absorbing byproduct CO2 surrounded by a porous shell of Al2O 3 which supported a Ni catalyst. The best results were achieved by incorporating 5 wt % limestone in the shell material to suppress coking. By employing the best core-in-shell pellets and supplying a 3:1 mol ratio ...


The Influence Of Alkali And Alkaline Earth Metals And The Role Of Acid Pretreatments In Production Of Sugars From Switchgrass Based On Solvent Liquefaction, Xianglan Bai, Robert C. Brown, Jie Fu, Brent H. Shanks, Matthew Kieffer Jan 2014

The Influence Of Alkali And Alkaline Earth Metals And The Role Of Acid Pretreatments In Production Of Sugars From Switchgrass Based On Solvent Liquefaction, Xianglan Bai, Robert C. Brown, Jie Fu, Brent H. Shanks, Matthew Kieffer

Chemical and Biological Engineering Publications

This study investigated the influence of alkali and alkaline earth metals (AAEM) and the role of acid pretreatments in the production of sugars during solvent liquefaction of lignocellulosic biomass using 1,4-dioxane and water as solvents. The present study found that removal of AAEM by acid washing/water rinsing did not enhance sugar production during solvent liquefaction of pretreated switchgrass nearly to the extent observed for fast pyrolysis nor did it inhibit lignin decomposition, suggesting that AAEM play less of a role in determining product yields in solvent liquefaction. On the other hand, acid infusion greatly enhanced the yields of ...


Sodium Ion Interactions With Aqueous Glucose: Insights From Quantum Mechanics, Molecular Dynamics, And Experiment, Heather B. Mayes, Jianhui Tian, Michael W. Nolte, Brent H. Shanks, Gregg T. Beckham, S. Gnanakaran, Linda J. Broadbelt Jan 2014

Sodium Ion Interactions With Aqueous Glucose: Insights From Quantum Mechanics, Molecular Dynamics, And Experiment, Heather B. Mayes, Jianhui Tian, Michael W. Nolte, Brent H. Shanks, Gregg T. Beckham, S. Gnanakaran, Linda J. Broadbelt

Chemical and Biological Engineering Publications

In the last several decades, significant efforts have been conducted to understand the fundamental reactivity of glucose derived from plant biomass in various chemical environments for conversion to renewable fuels and chemicals. For reactions of glucose in water, it is known that inorganic salts naturally present in biomass alter the product distribution in various deconstruction processes. However, the molecular-level interactions of alkali metal ions and glucose are unknown. These interactions are of physiological interest as well, for example, as they relate to cation-glucose cotransport. Here, we employ quantum mechanics (QM) to understand the interaction of a prevalent alkali metal, sodium ...


Cemox-Promoted Ketonization Of Biomass-Derived Carboxylic Acids In The Condensed Phase, Ryan William Snell, Brent H. Shanks Jan 2014

Cemox-Promoted Ketonization Of Biomass-Derived Carboxylic Acids In The Condensed Phase, Ryan William Snell, Brent H. Shanks

Chemical and Biological Engineering Publications

Ketonization of the model bio-oil compound acetic acid was performed in a toluene-solvent condensed phase using five different CeMOx catalysts. The catalysts were characterized using a number of different techniques both before and after reaction testing to gain understanding of how material traits influence their catalytic performance. A number of potentially important catalytic properties were found to be of little importance for the respective reaction. For instance, it was discovered that there was no direct correlation between prereaction surface area with activity for ketonization at high or at low temperatures. Furthermore, better reducibility of the oxide did not appear to ...


Multiple-Input Subject-Specific Modeling Of Plasma Glucose Concentration For Feedforward Control, Kaylee Renee Kotz, Ali Cinar, Yong Mei, Amy Roggendorf, Elizabeth Littlejohn, Laurie Quinn, Derrick K. Rollins Sr. Jan 2014

Multiple-Input Subject-Specific Modeling Of Plasma Glucose Concentration For Feedforward Control, Kaylee Renee Kotz, Ali Cinar, Yong Mei, Amy Roggendorf, Elizabeth Littlejohn, Laurie Quinn, Derrick K. Rollins Sr.

Chemical and Biological Engineering Publications

The ability to accurately develop subject-specific, input causation models, for blood glucose concentration (BGC) for large input sets can have a significant impact on tightening control for insulin dependent diabetes. More specifically, for Type 1 diabetics (T1Ds), it can lead to an effective artificial pancreas (i.e., an automatic control system that delivers exogenous insulin) under extreme changes in critical disturbances. These disturbances include food consumption, activity variations, and physiological stress changes. Thus, this paper presents a free-living, outpatient, multiple-input, modeling method for BGC with strong causation attributes that is stable and guards against overfitting to provide an e ffective ...


Understanding Biocatalyst Inhibition By Carboxylic Acids, Laura R. Jarboe, Liam Royce, Ping Liu Sep 2013

Understanding Biocatalyst Inhibition By Carboxylic Acids, Laura R. Jarboe, Liam Royce, Ping Liu

Chemical and Biological Engineering Publications

Carboxylic acids are an attractive biorenewable chemical in terms of their flexibility and usage as precursors for a variety of industrial chemicals. It has been demonstrated that such carboxylic acids can be fermentatively produced using engineered microbes, such as Escherichia coli andSaccharomyces cerevisiae. However, like many other attractive biorenewable fuels and chemicals, carboxylic acids become inhibitory to these microbes at concentrations below the desired yield and titer. In fact, their potency as microbial inhibitors is highlighted by the fact that many of these carboxylic acids are routinely used as food preservatives. This review highlights the current knowledge regarding the ...


Influence Of Carbon To Nitrogen Ratios On Soybean Somatic Embryo (Cv. Jack) Growth And Composition, Quyen Xuan Truong, Kaelynn Adele Koch, Jong Moon Yoon, John D. Everard, Jacqueline V. Shanks Jun 2013

Influence Of Carbon To Nitrogen Ratios On Soybean Somatic Embryo (Cv. Jack) Growth And Composition, Quyen Xuan Truong, Kaelynn Adele Koch, Jong Moon Yoon, John D. Everard, Jacqueline V. Shanks

Chemical and Biological Engineering Publications

Soybean [Glycine max (L.) Merr.] seed are valued for their protein and oil content. Soybean somatic embryos cultured in Soybean Histodifferentiation and Maturation (SHaM) medium were examined for their suitability as a model system for developing an understanding of assimilate partitioning and metabolic control points for protein and oil biosynthesis in soybean seed. This report describes the growth dynamics and compositional changes of SHaM embryos in response to change in the carbon to nitrogen ratio of the medium. It was postulated that at media compositions that were sufficient to support maximal growth rates, changes in the C:N ratio are ...


Substrate Binding By The Catalytic Domain And Carbohydrate Binding Module Of Ruminococcus Flavefaciens Fd-1 Xyloglucanase/ Endoglucanase, Christopher D. Warner, Gulden Camci-Unal, Nicola L.B. Pohl, Clark Ford, Peter J. Reilly Jan 2013

Substrate Binding By The Catalytic Domain And Carbohydrate Binding Module Of Ruminococcus Flavefaciens Fd-1 Xyloglucanase/ Endoglucanase, Christopher D. Warner, Gulden Camci-Unal, Nicola L.B. Pohl, Clark Ford, Peter J. Reilly

Chemical and Biological Engineering Publications

Binding and thermodynamic properties of a carbohydrate binding module (CBM) and a glycoside hydrolase family 44 xyloglucanase/endoglucanase catalytic domain (CD) fromRuminococcus flavefaciens, both when separate and when linked to each other, have been quantified when binding various β-1,4-linked glucans and xylans. The three constructs bind cellotetraose, cellopentaose, and cellohexaose with association constants that increase with chain length. The CBM does not bind xylotetraose, xylopentaose, or xylohexaose. The CD appears to bind carboxymethylcellulose (CMC) and xylan only weakly, while the CBM and the CD/CBM bind them much more strongly than they bind the cellooligosaccharides. CMC is bound ...


Integrated Self-Assembly Of The Mms6 Magnetosome Protein To Form An Iron-Responsive Structure, Shuren Feng, Lijun Wang, Pierre Palo, Xunpei Liu, Surya K. Mallapragada, Marit Nilsen-Hamilton Jan 2013

Integrated Self-Assembly Of The Mms6 Magnetosome Protein To Form An Iron-Responsive Structure, Shuren Feng, Lijun Wang, Pierre Palo, Xunpei Liu, Surya K. Mallapragada, Marit Nilsen-Hamilton

Chemical and Biological Engineering Publications

A common feature of biomineralization proteins is their self-assembly to produce a surface consistent in size with the inorganic crystals that they produce. Mms6, a small protein of 60 amino acids from Magnetospirillum magneticum strain AMB-1 that promotes the in vitro growth of superparamagnetic magnetite nanocrystals, assembles in aqueous solution to form spherical micelles that could be visualized by TEM and AFM. The results reported here are consistent with the view that the N and C-terminal domains interact with each other within one polypeptide chain and across protein units in the assembly. From studies to determine the amino acid residues ...


Combinatorial Evaluation Of In Vivo Distribution Of Polyanhydride Particle-Based Platforms For Vaccine Delivery, Latrisha K. Petersen, Lucas Mark Huntimer, Katharine Walz, Amanda Ellen Ramer-Tait, Michael J. Wannemuehler, Balaji Narasimhan Jan 2013

Combinatorial Evaluation Of In Vivo Distribution Of Polyanhydride Particle-Based Platforms For Vaccine Delivery, Latrisha K. Petersen, Lucas Mark Huntimer, Katharine Walz, Amanda Ellen Ramer-Tait, Michael J. Wannemuehler, Balaji Narasimhan

Chemical and Biological Engineering Publications

Several challenges are associated with current vaccine strategies, including repeated immunizations, poor patient compliance, and limited approved routes for delivery, which may hinder induction of protective immunity. Thus, there is a need for new vaccine adjuvants capable of multi-route administration and prolonged antigen release at the site of administration by providing a depot within tissue. In this work, we designed a combinatorial platform to investigate the in vivo distribution, depot effect, and localized persistence of polyanhydride nanoparticles as a function of nanoparticle chemistry and administration route. Our observations indicated that the route of administration differentially affected tissue residence times. All ...


Tin Dioxide-Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Wilinger, Nicola Donato, Giovanni Neri, Nicola Pinna Jan 2013

Tin Dioxide-Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Wilinger, Nicola Donato, Giovanni Neri, Nicola Pinna

Chemical and Biological Engineering Publications

Carbon materials such as carbon nanotubes (CNTs), graphene, and reduced graphene oxide (RGO) exhibit unique electrical properties, which are also influenced by the surrounding atmosphere. They are therefore promising sensing materials. Despite the existence of studies reporting the gas-sensing properties of metal oxide (MOx) coated nanostructured carbon, an incomplete understanding of their sensing mechanism remains. Here we report a systematic study on the preparation, characterization, and sensing properties of CNT and RGO composites with SnO2 coating. Atomic layer deposition (ALD) was applied to the conformal coating of the inner and outer walls of CNTs with thin films of SnO2 of ...


Insights Into The Ceria-Catalyzed Ketonization Reaction For Biofuels Applications, Ryan William Snell, Brent H. Shanks Jan 2013

Insights Into The Ceria-Catalyzed Ketonization Reaction For Biofuels Applications, Ryan William Snell, Brent H. Shanks

Chemical and Biological Engineering Publications

The ketonization of small organic acids is a valuable reaction for biorenewable applications. Ceria has long been used as a catalyst for this reaction; however, under both liquid and vapor phase conditions, it was found that given the right temperature regime of about 150-300 °C, cerium oxide, which was previously believed to be a stable catalyst for ketonization, can undergo bulk transformations. This result, along with other literature reports, suggest that the long held belief of two separate reaction pathways for either bulk or surface ketonization reactions are not required to explain the interaction of cerium oxide with organic acids ...