Biochemical and Biomolecular Engineering Commons^™

Protein Release Study Using Heparin Modified Methacrylamide Chitosan Hydrogels, Dakotah G. Cox

Williams Honors College, Honors Research Projects

This study was performed to improve the release of proteins from hydrogels in order to increase their effectiveness in treating spinal cord injuries. Heparin, which has the ability to bind to proteins and slow their release, underwent methacrylation, was added to prepared methacrylamide chitosan (MAC) solutions with a model protein (SDF-1α) and photopolymerized to create MAC-heparin hydrogels. Varying weight percentages of methacrylated heparin were tested in order to determine the optimal amount needed to improve the release profile. The pure MAC hydrogels and gels with 10 wt% heparin had a rapid release of the SDF-1α (>23% and >29%, respectively, …

The Influence Of Light On The Electrochemical Characteristics Of Pure Aluminum, Hongbo M. Cong

Williams Honors College, Honors Research Projects

The objective of this work was to study the influence of light (wave length ~ 460 nm) on the electrochemical characteristics of pure aluminum. The open circuit potential (OCP) measurements, potentiostatic polarization, cyclic potentiodynamic polarization and Zero Resistance Ammetry (ZRA) were performed in 0.1 M NaCl solution. It was observed that the incident light shifted the OCP in the noble direction by 100 mV. Furthermore, ZRA was performed to measure the galvanic current between illuminated and non-illuminated aluminum electrodes. Cyclic potentiodynamic polarization tests revealed the influence of light on the pitting potential, passive current density, corrosion current density, and repassivation …

The Effect Of Drying On The Release Of Small Hydrophilic Molecular Drugs From Polyelectrolyte Complex Beads, Dounsavanh Letdara

Williams Honors College, Honors Research Projects

The effects of bead composition and dryness on the release rate of small molecules, like a drug or dye, from polyelectrolyte complex (PEC) beads were studied. Release studies were performed on dried and not dried beads prepared using different PEC to drug ratios. The beads were dried for two hours, which allowed them to reach a constant weight. The beads were loaded with a dye, so their release could be detected through the visible light regime. A plate reader was used to determine the absorbance of a sample, and then the amount of dye released was determined. The data presented …

Microbiologically Influenced Corrosion: Rhamnolipid Effects, Andrea M. Wildroudt

Williams Honors College, Honors Research Projects

The purpose of this experiment was to identify if a rhamnolipid could inhibit the growth of a biofilm on carbon steel coupons and result in less corrosion activity. This type of research impacts various industries (with one of the largest being the oil and gas industry). Multiple systems with varying concentrations of the rhamnolipid were created to determine, if any, the optimum concentration to inhibit biofilm growth. The systems were created and exposed to optimum physio-chemical environments to promote SRB induced corrosion. Coupons were immersed for 28 days. Seven systems were created with varying rhamnolipid concentrations; to ensure accurate results, …

Calcium Alginate Microbead Production Via An Air Assisted Shearing Process, Ryan Loftus

Williams Honors College, Honors Research Projects

The purpose of this project was to model the size of calcium alginate microbeads produced by extruding a solution of 1.5 wt.% alginate from a syringe and needle with air shear generated from a pneumatic line flowing in an annular tube around the extrusion needle. The air shear would create microdroplets that would fall into a solution of 2 wt.% calcium chloride in water, crosslinking the droplets into beads. These microbeads can be used in drug dispersion applications or in encapsulation of cells throughout the body due to their biocompatibility. The goal was to create uniform beads that ranged from …

Protein Sequence-Structure-Function Relationship: Testing Ke-50 Modification On Recombinant Green Fluorescent Protein (Acgfp), Anna E. Burkey

Williams Honors College, Honors Research Projects

Protein modification shows promise for improving the effectiveness of protein therapy, including the use of Interferon-beta-1b for the treatment of multiple sclerosis. The addition of a chain of 50 lysine and glutamic acid residues (also called a KE50 modification) was tested on green fluorescent protein (AcGFP) to determine its effect on the bioactivity of the protein. Standard transformation protocol was used to grow the normal and modified proteins in E.Coli, and the bioactivity of the protein was measured using quantum yield and extinction coefficients to determine the reduction in brightness from the native form to the modified form. The …

Construction Of Polyurethane Fabric Nanocomposites For Use In Resistance Temperature Detectors-Effect Of Polyurethane Concentration, Multi-Walled Carbon Nanotubes, And Oxidant, Jordan M. Shaffer

Williams Honors College, Honors Research Projects

Current resistance temperature detectors (RTDs) are rigid and create pressure points when used in contact with the human body. The current RTDs can also not be used in confined areas like the inside of a prosthetic. The research done for this paper explores the possibility of creating a soft fabric like RTD that can accurately measure temperature. This RTD could be used in medical devices, be placed in prosthetic legs, and be worn for a long period of time creating no discomfort for the user. Polyurethane scaffolds were created through an electrospinning process and multiwalled carbon nanotubes were adhered to …

Thermal Responsive Release Of A Model Drug, Rhoadmine B, From Alginate Bead System, Heather F. Fairbairn Miss

Williams Honors College, Honors Research Projects

Smart drug delivery systems have garnered increased interest in the biomedical community during recent years. Investigation into thermal, pH, and light responsive delivery systems allows for targeted drug release systems to be developed. For this project, thermal responsive release behavior was investigated for the purpose of tuning release systems to achieve 60% release in a specified time by varying the content of thermal responsive polymer. To investigate this, the release profile of a model small hydrophilic drug (rhodamine B) from polymeric alginate beads that have been modified by the addition of thermal responsive poly(N-isopropylacrylamide) (PNIPAAm). It was determined that when …

A Versatile Microparticle-Based Immunoaggregation Assay For Macromolecular Biomarker Detection And Quantification, Haiyan Wu, Yu Han, George G. Chase, Qiong Tang, Chen-Jung Lee, Bin Cao, Jiang Zhe, Gang Cheng

Mechanical Engineering Faculty Research

The rapid, sensitive and low-cost detection of macromolecular biomarkers is critical in clinical diagnostics, environmental monitoring, research, etc. Conventional assay methods usually require bulky, expensive and designated instruments and relative long assay time. For hospitals and laboratories that lack immediate access to analytical instruments, fast and low-cost assay methods for the detection of macromolecular biomarkers are urgently needed. In this work, we developed a versatile microparticle (MP)-based immunoaggregation method for the detection and quantification of macromolecular biomarkers. Antibodies (Abs) were firstly conjugated to MP through streptavidin-biotin interaction; the addition of macromolecular biomarkers caused the aggregation of Ab-MPs, which were subsequently …

Predicting Key Residues Relevant To Hiapp Fibril Stability Using Permuted Residue Minimal Distance Pairs Of Riapp And Hiapp Dimers, Zak Kohler

Williams Honors College, Honors Research Projects

In order to discover the most significant residues involved in hIAPP fibril formation, Replica Exchange Molecular Dynamics (REMD) trajectories of both fibril forming hIAPP dimers and non-fibril-forming rIAPP dimers were analyzed. An import heuristic for this is the minimum distance between the peptides. To gain a greater resolution than the standard center of mass distance or 1-1, 2-2, etc.\ residue distances, every permutation of residue distance between molecules of the dimer was measured ranked. It was found that while the rIAPP had a single favored contact, (26 10), hIAPP appeared to have a network of at least three significant contacts: …

Formation Of Polymer Micro-Tubes, Daniel Peters

Williams Honors College, Honors Research Projects

Abstract

Current demand for organs is greater than the supply of donated organs, which means that a new method of obtaining replacement organs needs to be found. The objective of the research is to evaluate the use of thermo-triggered self-rolling polymer tubes that can be used for scaffolds in tissue engineering. Additionally, the research also includes a method for forming polymer tubes through the removal of a sugar fiber, coated with a thin film of polymer, by dissolving it in deionized water. For the first approach, the effect of the aqueous environment and temperature on a polymer bilayer was observed …

Determining The Critical Micelle Concentration Of Polymer Matrix For Drug Delivery Purposes, Katie Emmert

Williams Honors College, Honors Research Projects

Targeted oral release systems have been a large topic within drug delivery systems. There are several benefits to an oral delivery including patient convenience and lower chance of infection. The colon specifically has been researched as the release media. The colon is an ideal location for a release because the pH is stable with high levels of microorganisms. Like any type of drug delivery research, there are several hurdles to overcome. In order for a drug to be released in the colon, the drug must survive the stomach and be biocompatible. This biocompatibility and pH sensitivity was created using a …

Evaluation Of The Signature Molecular Descriptor With Blosum62 And An All-Atom Description For Use In Sequence Alignment Of Proteins, Lindsay M. Aichinger

Williams Honors College, Honors Research Projects

This Honors Project focused on a few aspects of this topic. The second is comparing the molecular signature kernels to three of the BLOSUM matrices (30, 62, and 90) to test the accuracy of the mathematical model. The kernel matrix was manipulated in order to improve the relationship by focusing on side groups and also by changing how the structure was represented in the matrix by increasing the initial height distance from the central atom (Height 1 and Height 2 included).

There were multiple design constraints for this project. The first was the comparison with the BLOSUM matrices (30, 62, …

Polymer Interactions With Nucleic Acids Under Various Physiological Conditions, Matthew S. Obrzut

Williams Honors College, Honors Research Projects

The goal of this project is to improve our understanding of nucleic acid interactions with cationic polymers with the theory that the polymers could protect the nucleic acids from degradation caused by biological enzymes. We seek to understand what the limitations of the cationic polymers are which, in this case, is mainly polymer-DNA compatibility. This experiment utilized peptide-dextran hybrid polymers with differing functionalizations to condense anionic nucleic acids into nanometer-sized polyplexes. Techniques of dynamic light scattering and zeta-potential were utilized to determine the particle sizes and surface charges of polyplexes.

In this experiment, dextran with a molecular weight of 20 …

New Multiphase Reactor Design Using Electrospun Nanofibers, Victoria Smith

Williams Honors College, Honors Research Projects

No abstract provided.

3d Differentiation Of Neural Stem Cells In Macroporous Photopolymerizable Hydrogel Scaffolds, Nic Leipzig

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Neural stem/progenitor cells (NSPCs) are the stem cell of the adult central nervous system (CNS). These cells are able to differentiate into the major cell types found in the CNS (neurons, oligodendrocytes, astrocytes), thus NSPCs are the mechanism by which the adult CNS could potentially regenerate after injury or disorder. Microenviromental factors are critical for guiding NSPC differentiation and are thus important for neural tissue engineering. In this study, D-mannitol crystals were mixed with photocrosslinkable methacrylamide chitosan (MAC) as a porogen to enhance pore size during hydrogel formation. D-mannitol was admixed to MAC at 5, 10 and 20 wt% D-mannitol …

Fabrication And Degradation Of Electrospun Scaffolds From L-Tyrosine Based Polyurethane Blends For Tissue Engineering Applications, Lingyun Liu

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

It is important to control the degradation rate of a tissue-engineered scaffold so that the scaffold will degrade in an appropriate matching rate as the tissue cells grow in. A set of potential tissue engineering scaffolds with controllable rates of degradation were fabricated from blends of two biocompatible, biodegradable L-tyrosine-based polyurethanes (PEG1000-HDI-DTH and PCL1250-HDI-DTH) using the electrospinning process. The scaffolds were characterized by mat morphology, fiber diameter, diameter distribution, pore size, and hydrolytic degradation behavior. The majority of the scaffolds, despite having radically different chemical compositions, possessed no statistical difference with pore sizes and fiber diameters. The degradation pattern observed …

Polymorphic Structures Of Alzheimer's Beta-Amyloid Globulomers, Jie Zheng

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Misfolding and self-assembly of Amyloid-β (Aβ) peptides into amyloid fibrils is pathologically linked to the development of Alzheimer's disease. Polymorphic Aβ structures derived from monomers to intermediate oligomers, protofilaments, and mature fibrils have been often observed in solution. Some aggregates are on-pathway species to amyloid fibrils, while the others are off-pathway species that do not evolve into amyloid fibrils. Both on-pathway and off-pathway species could be biologically relevant species. But, the lack of atomic-level structural information for these Aβ species leads to the difficulty in the understanding of their biological roles in amyloid toxicity and amyloid formation.

Hemocompatibility Of Silicon-Based Substrates For Biomedical Implant Applications, Lingyan Liu

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Silicon membranes with highly uniform nanopore sizes fabricated using microelectromechanical systems (MEMS) technology allow for the development of miniaturized implants such as those needed for renal replacement therapies. However, the blood compatibility of silicon has thus far been an unresolved issue in the use of these substrates in implantable biomedical devices. We report the results of hemocompatibility studies using bare silicon, polysilicon, and modified silicon substrates. The surface modifications tested have been shown to reduce protein and/or platelet adhesion, thus potentially improving biocompatibility of silicon. Hemocompatibility was evaluated under four categories—coagulation (thrombin–antithrombin complex, TAT generation), complement activation (complement protein, C3a …

Surface Hydration: Principles And Applications Toward Low-Fouling/Nonfouling Biomaterials, Lingyan Liu, Jie Zheng

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Surface resistance to nonspecific protein adsorption, cell/bacterial adhesion, and biofilm formation is critical for the development and performance of biomedical and analytical devices. Significant needs and efforts have been made in the development of biocompatible and bioactive materials for antifouling surfaces, but much of the work retains an empirical flavor due to the complexity of experiments and the lack of robust theoretical models. In this review, two major classes of nonfouling materials (i.e. hydrophilic and zwitterionic materials) and associated basic nonfouling mechanisms and practical examples are discussed. Highly hydrated chemical groups with optimized physical properties of the surface, along with …

Ptau Bimetallic Heteronanostructures Made By Post-Synthesis Modification Of Pt-On-Au Nanoparticles, Zhenmeng Peng

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

imetallic PtAu heteronanostructures have been synthesized from Pt-on-Au nanoparticles, which were made from platinum acetylacetonate and gold nanoparticles. Using the Pt-on-Au nanoparticles as precursors, Ptsurface rich PtAu bimetallic heteronanostructures can be produced through controlled thermal treatments, as confirmed by field emission high-resolution transmission electron microscopy (HR-TEM) and elemental mapping using a high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM). Oxidation of formic acid was used as a model reaction to demonstrate the effects of varying composition and surface structure on the catalytic performance of PtAu bimetallic nanostructures. Cyclic voltammetry (CV) showed that these carbon-supported PtAu heteronanostructures were much more active …

Promoting Neuron Adhesion And Growth, Laura M. Y. Yu, Nic Leipzig, Molly S. Schoichet

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

During nervous system development, the extracellular matrix (ECM) plays a pivotal role offering anchorage points to maturing neurons and neurites, as well as a permissive environment for tissue formation. Thus enhancement of cell adhesion is often an important criterion when designing biomaterials for neural tissue engineering. In addition to functionalizing biomaterials with ECM-derived cell adhesive molecules, there is emerging evidence that indicates the surface topography, stiffness, and electrical properties play an important role in neuron adhesion and neurite outgrowth. We describe recent developments in biomaterials modification for simulating the microenvironment in order to promote neuron adhesion and growth, as well …

The Effects Of Tgf-Beta1 And Igf-I On The Biomechanics And Cytoskeleton Of Single Chondrocytes, Nic Leipzig

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Objective Ascertaining how mechanical forces and growth factors mediate normal and pathologic processes in single chondrocytes can aid in developing strategies for the repair and replacement of articular cartilage destroyed by injury or disease. This study examined effects of transforming growth factor-β1 (TGF-β1) and insulin-like growth factor-I (IGF-I) on the biomechanics and cytoskeleton of single zonal chondrocytes. Method Superficial and middle/deep bovine articular chondrocytes were seeded on tissue culture treated plastic for 3 and 18 h and treated with TGF-β1 (5 ng/mL), IGF-I (100 ng/mL), or a combination of TGF-β1 (5 ng/mL) + IGF-I (100 ng/mL). Single chondrocytes from all …

Designing A Nanotube Using Naturally Occurring Protein Building Blocks, Jie Zheng

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Here our goal is to carry out nanotube design using naturally occurring protein building blocks. Inspection of the protein structural database reveals the richness of the conformations of proteins, their parts, and their chemistry. Given target functional protein nanotube geometry, our strategy involves scanning a library of candidate building blocks, combinatorially assembling them into the shape and testing its stability. Since self-assembly takes place on time scales not affordable for computations, here we propose a strategy for the very first step in protein nanotube design: we map the candidate building blocks onto a planar sheet and wrap the sheet around …