Search results

Title: MODEL-BASED EXPLORATION OF THE FEASIBILITY OF CREATING MULTIPLE PROPERTY GRADIENT IN CROSSLINKED POLYMER FILMS IN CONTROLLED LIVING POLYMERIZATION
Creator: Qin, Zikai
Date: 2014, 2014-05
Description: The functional gradient materials have been widely used in chemical engineering, biomedical engineering and tissue engineering since they have...
Show moreThe functional gradient materials have been widely used in chemical engineering, biomedical engineering and tissue engineering since they have been reported because of their admirable mechanical, physical and chemical properties. Several traditional methods of synthesis gradient materials are known to all. Here we introduced a new mathematical model of designing and producing crosslinked polymeric films with target multiple gradients. We derive our model from batch reactor system and explore how each condition of the system affects the gradient of the polymer film. Then we extend to semi-batch reactor to control the gradient in crosslink density and set up different strategies to make the target multiple gradient crosslink density accomplish. With any given target gradient crosslinked polymer film, we can make an exact similar film in our model.
M.S. in Chemical Engineering, May 2014
Show less

Title: FLIP-FLOP JET NOZZLE EXTENDED TO SUPERSONIC FLOWS
Creator: Raman, G, Hailye, M, Rice, Ej
Date: 1993-06
Publisher: AMER INST AERONAUT ASTRONAUT
Description: An experiment studying a fluidically oscillated rectangular jet flow was conducted. The Mach number was varied over a range from low subsonic...
Show moreAn experiment studying a fluidically oscillated rectangular jet flow was conducted. The Mach number was varied over a range from low subsonic to supersonic. Unsteady velocity and pressure measurements were made using hot wires, piezoresistive pressure transducers, and pitot probes. In addition, smoke flow visualization using high-speed photography was used to document the oscillation of the jet. For the subsonic flip-flop jet, it was found that the apparent time-mean widening of the jet was not accompanied by an increase in the mass flux. Fluidically oscillated jets up to a Mach number of about 0.5 have been reported before, but to our knowledge there is no information on fluidically oscillated supersonic jets. It was found that it is possible to extend the operation of these devices to supersonic flows. The streamwise velocity perturbation levels produced by this device were much higher than the perturbation levels that could be produced using conventional excitation sources such as acoustic drivers. In view of this ability to produce high amplitudes, the potential for using a small-scale fluidically oscillated jet as an unsteady excitation source for the control of shear flows in full-scale practical applications seems promising.
Show less

Title: SENSITIVITY ANALYSIS: INFLUENCE OF INFLUENT VARIABLES ON A WRP MODEL
Creator: Wang, Xiaolong
Date: 2015, 2015-07
Description: Balancing between cost and effluent quality at the Calumet water reclamation plants (WRP) is important. Influent quality has strong effects on...
Show moreBalancing between cost and effluent quality at the Calumet water reclamation plants (WRP) is important. Influent quality has strong effects on effluent quality. In this study, based on a simulation model, the influence of influent parameters on effluent ammonia concentration is identified by sensitivity analysis methods. Nine sensitivity analysis methods, including two mathematical methods, five statistical methods, and two graphical methods, are presented. Using different sensitivity analysis, most results presented all main effects have stronger effects than interactions among input variables on the output. Water temperature is always the most important parameter; the most important interaction effect is between water temperature and SS. Key words: Sensitivity analysis; water reclamation plants; design of experiments; simulation model; influent water quality; effluent ammonia
M.S. in Environmental Engineering, July 2015
Show less

Title: THE PALAIS GARNIER: TOWARD AN ARCHITECTURE OF DANCE AND MUSIC IN XIX CENTURY FRANCE
Creator: Vranas Olsen, Cynthia
Date: 2017, 2017-05
Description: As a doctoral candidate, this writer has focused on the Romantic Movement of 19th century France, where the arts mutually influenced each...
Show moreAs a doctoral candidate, this writer has focused on the Romantic Movement of 19th century France, where the arts mutually influenced each other, just as in ancient Greece and Rome. This research highlights the interrelationships of the Arts to Architecture by examining artists such as Hugo in drama, Gautier in literature, Delacroix in painting, Chopin and Adam in music, Noverre in dance and Garnier in architecture. Although Noverre’s specialty was dance, he believed that theater buildings were first monuments to the arts. For Garnier, 100 years later, the Arts and Architecture were not separate identities. They complemented and enhanced one another. Both books, Observations sur la Construction d’une Nouvelle Salle de l’Opera by Jean-Georges Noverre and Le Theatre by Charles Garnier, were publications translated extensively from French to the English language as primary sources. In designing a theater building, the architect is responsible for synthesizing and translating myriad information in order to create an appropriate and responsive language. An invaluable knowledge of technical considerations - set design, lighting, backstage equipment, sightlines, acoustics and facilities for performers - is critical, as is balancing the client’s concerns and the user/spectator’s needs. As performance expresses a cultural instinct for communicative involvement, this writer believes that a theater building, itself, is a reflection of the arts. It is art, therefore, that inextricably shapes the programs and designs of our theater buildings. The Palais Garnier, completed in 1875 for the Paris Opéra and its associated Paris Opéra Ballet, is thought to mirror the cultural complexity of the age. Before this time, the Paris Opéra was housed in the Salle Le Peletier, a temporary building with inadequate facilities that did not reflect the existing, lavish, highly skilled art that was performed. Garnier’s travels to ancient sites in Greece and Rome resulted in his classic book, Le Théatre. By writing, he immersed himself in the study of the physical qualities of the theater, and it eventually became his architecture. The form and character of the theater buildings studied reflect the changing social structures, technology and patronage that sponsored them. The Palais Garnier reflects a unique intersection of the arts, along with the political, social and economic influences of that time. Musicians turned their attention toward the expressions of intense feelings that were influenced by poetry and the visual arts. The Palais Garnier, with its grandeur and opulence, became its own “performance”. The multi-disciplinary nature of architecture and the study of the interrelationships of the arts can inform creativity. Just like the timeless, majestic Palais Garnier in Paris, in 19th century France, new architectural structures can become their own profound monumental and memorable “performances” for future generations.
Ph.D. in Architecture, May 2017
Show less

Title: Facade Retrofit - High Performance Facade Systems for an Existing Building
Creator: Velichkova, Gergana
Date: 5/4/2011, 2011-05
Description: THE FAÇADE HAS THE HIGHEST POTENTIAL WHEN TRYING TO OPTIMIZE THE ENERGY PERFORMANCE OF A BUILDING. THE MAIN GOAL OF THE PROJECT IS TO...
Show moreTHE FAÇADE HAS THE HIGHEST POTENTIAL WHEN TRYING TO OPTIMIZE THE ENERGY PERFORMANCE OF A BUILDING. THE MAIN GOAL OF THE PROJECT IS TO INVESTIGATE WHAT IS THE VALUE OF FACADE RETROFIT AND STUDY THE RELATIONSHIP BETWEEN PERFORMANCE, WEIGHT, EMBODIED ENERGY, ASSEMBLY EFFORT, COST AND POTENTIAL SAVINGS. 4 DIFFERENT FACADE SYSTEMS ARE ANALYZED AND COMPARED IN THE CONTEXT OF AN EXISTING BUILDING. ONE OF THE SYSTEMS IS CURRENTLY INSTALLED AND HAS BEEN RECENTLY RETROFITTED, WHILE THE OTHER THREE ARE DESIGN PROPOSALS WHICH FOCUS ON THE FOLLOWING ASPECTS: PERFORMANCE AND DAYLIGHT, MINIMAL STRUCTURE AND ADAPTABILITY.
Sponsorship: Sobek, Werner
Show less

Title: Delta Shelter (sequence unknown), IPRO 311 - Deliverables: 311
Creator: Schug, Timothy, Bradley, Joshua, Cahan, Noah, Dobbin, Dan, Hallenbeck, Jeff, Jordan, Davyd, Strandquist, Brad, Dohm, Jacob, Hoffman, Kent, Lee, Woong-kyo, Waisath, Nathan
Date: 2009-12
Description: The Delta Tau Delta fraternity wants to make their current house as energy efficient and green as possible. The team will look at all aspects...
Show moreThe Delta Tau Delta fraternity wants to make their current house as energy efficient and green as possible. The team will look at all aspects of the DTD house and their operations to create a more energy efficient fraternity. During the term, the team will consider possible alternatives to many issues including but not limited to: mechanical heating system, building envelope, thermal properties of buildings perimeter, roofing materials, air infiltration, ventilation, and occupancy trends.
Deliverables for IPRO 311: Delta Shelter for the fall 2009
Show less

Title: Impacts of Sulfur Capture Technology in Coal Power Plants (sequence unknown), IPRO 302 - Deliverables: IPRO 302 Poster F09
Creator: Contreras, Abraham, Dickman, Justin, Enadeghe, Gregory, Garcia Rodriguez, Hector, Haddad, Michael, Kyle, Ryan, Mongillo, Michael, Murphy, Ryan, Shonubi, Oluwaseun, Swillum, Bryce, Wolber, Brian, Worthon, Terrika
Date: 2009-12
Description: The IPRO team was investigating the net impact of sulfur capture technologies used in current and next generation power plants in the United...
Show moreThe IPRO team was investigating the net impact of sulfur capture technologies used in current and next generation power plants in the United States. It planned to use this knowledge to determine which sulfur capture technologies produce the greatest benefit for industry and society and to find the marketability of the sulfur byproducts created in these power plants.
Sponsorship: Sargent & Lundy, LLC
These are the deliverables for IPRO 302: Impacts of Sulfur Capture Technology in Coal Power Plants from the Fall 2009 semester.
Show less

Title: Agricultural Rehabilitation Tower: Thesis Project_RGG_JYL
Creator: Garcia, Rodrigo, Lee, Jennifer
Date: 5/4/2011, 2011-05
Description: to create a vertical community bound together by two key issues/requirements in Korean society: urban agriculture and mental health care to...
Show moreto create a vertical community bound together by two key issues/requirements in Korean society: urban agriculture and mental health care to create a ‘vertical façade farm’ capable of producing 156 tons of vegetables (predominantly lettuce, tomatoes, peppers, and strawberries) and 200 tons of fish per year to create a mental health sanctuary (or sanatorium) that provides short term (days), midterm (months) and long term (years) residence and care for people with mental health issues that may require physical operations and/or psychological care. to actively engage the mental health residents in aspects of the agricultural production to draw on research showing that engagement with plants/nature assists in mental healing. to create a large multi-purpose space at the ground floor of the building which will largely serve as a farmer’s market for sale of the agricultural produce and engagement between the community residents and the public to create a series of gardens/green spaces at height within the complex, as well as vertical green walls, for healing (residents and urban issues) to use the double-skin ‘façade farm’ for assisting in passive natural ventilation of internal spaces
Show less

Title: HIGH PERFORMANCE AND LOW POWER HARDWARE IMPLEMENTATION FOR CRYPTOGRAPHIC HASH FUNCTIONS
Creator: Zhang, Yunlong
Date: 2013-04-30, 2013-05
Description: In this thesis, we introduce hash encryption functions which are widely used in a number of protocols as digital signature to protect privacy...
Show moreIn this thesis, we introduce hash encryption functions which are widely used in a number of protocols as digital signature to protect privacy information. Since the hash algorithm can be speeded up and be more security by physical protection, hash function hardware implementation is more desired today for evaluating its performance and processing data with dramatically increased size. Then we consider those two problems in the hash function hardware implementation: throughput and power consumption. High level of throughput is significant for the efficiency of hash algorithm. By using unfolding transformation, the throughput of hash function can be increased apparently. However, power consumption, area and critical path delay will also be increased. Pipeline and parallelism is an effective technique to decrease the critical path delay, by analyzing the construction of computing process. Another Problem is power consumption which will influence the reliability and cost of device. Clock gating is a widely used and efficiency technique for dynamic power reducing at register transfer level (RTL). There are two basic modes for single level clock gating: XOR-based clock gating and load-enable based clock gating [13]. The former one is based on the comparing between output and input of flip-flops (FFs). Although this XOR-based clock gating technique is not used in our hash function hardware implementation, we will briefly introduce some techniques of this method which is our previous research work for dynamic power reduction by comparing some RTL low power techniques. x Next, load-enable based clock gating which works with an enable signal is introduced. According to the idle mode of some components in our simply hash encryption system, we use this load-enable based clock gating to eliminate wasted toggle rate of some signals, thus reducing dynamic power consumption. Finally, according to the source of dynamic power dissipation, reducing clock frequency is another choice. Frequency trade-off technique is proposed, which combines unrolling transformation with frequency scaling. In this technique, a scope of frequency value is given in each hash function with different number of iteration rounds for trading off low dynamic power consumption and high throughput.
M.S. in Electrical Engineering, May 2013
Show less

Title: Orthotics and Prosthetics in Latin America (sequence unknown), IPRO 309 - Deliverables: IPRO 309 Midterm Presentation F09
Creator: Ashley, Trevor, Claxton, Matt, Conover, Stephen, Gotanco, Francis, Mathai, Alexander, Nizich, Adam, Park, Yong, Quikr, Kerry, Ray, Monmayuri, Vasquez, Raul
Date: 2009-12
Description: The overall goal of our IPRO team is to create a program for delivering orthotics and prosthetics that is sustainable. This will be...
Show moreThe overall goal of our IPRO team is to create a program for delivering orthotics and prosthetics that is sustainable. This will be accomplished by improving the quality of the product by increasing availability of funding, improving cost effectiveness of prosthetics, and promoting awareness of treatment available.
Deliverables for IPRO 309: Orthotics and Prosthetics in Latin America for the fall 2009 semester.
Show less

Title: REAL TIME STATIC SCENE 3D RECONSTRUCTION USING DEPTH SENSORS FOR AUGMENTED TELEOPERATION
Creator: Srinivasan, Ranga Ramanujam
Date: 2015, 2015-05
Description: In the first part of this Master’s Thesis, literature survey is done to find the best performing algorithm in terms of real-time performance...
Show moreIn the first part of this Master’s Thesis, literature survey is done to find the best performing algorithm in terms of real-time performance and quality of 3D reconstruction from depth images. Kinfu of PCL is found to be the best in terms of real-time performance and maintainability, as it is open-source software, with thousands of users working on to improve it. The primary part of the thesis is to improve on the 3D reconstruction quality of Kinfu and this is achieved by improving on the three important stages of Kinfu, Depth Filtering, Pose-estimation and 3D reconstruction. A new Anisotropic depth filtering kernel is proposed and it is found to give 23% quantitative improvement over baseline Kinfu. A modified pose-estimation which incorporates the uncertainty or error characteristics of the depth measured as part of the ICP algorithm is proposed. This results in a 51% quantitative improvement and a big subjective quality improvement over baseline Kinfu. A similar approach based on depth error characteristics but applied to 3D reconstruction stage which is based on an already published paper [1], is implemented. All the improvements in each of the three stages are combined together, to get a robust, real-time 3D reconstruction framework.
M.S. in Electrical Engineering, May 2015
Show less

Title: Cure for the IKIA Syndrome : presented at IACRL 2008 conference
Creator: Uth, Charles, Link, Jeanne
Date: 2008-02
Description: Informal observations of a practical and creative approach piloting Blended Library Instruction for undergraduate Civil Architecture and...
Show moreInformal observations of a practical and creative approach piloting Blended Library Instruction for undergraduate Civil Architecture and Engineering students, in collaboration with faculty. At Illinois Institute of Technology students don’t receive library instruction as a required class or in tandem with a composition class. Faculty will schedule one-time sessions, which ideally should be planned with a class assignment in mind, but students are rarely engaged with a one time instruction. Many have IKIA syndrome or I Know It Already syndrome. The Millennials are a group that has integrated technology into every aspect of their lives and they assume that retrieving useful or necessary information will be easy. When they discover this isn’t the case lack of time, heightened anxiety, and increased frustration can prevent them from doing their best work. By intentionally creating a similar crisis prior to library instruction, students were more interested in what they stood to gain during pending library instruction. In this presentation we will discuss: 1) A creative means of delivering library instruction to a traditionally challenging population: engineering undergraduate students 2) Qualitative information collected via multiple assignments and interpreted in a quantitative fashion, as well as our observations. 3) A method for preparing students for library instruction that can be applied in almost any discipline without asking the instructor to sacrifice class time.
Show less

Title: Computational Aeroacoustics
Creator: Raman, Ganesh
Date: 2008
Publisher: Multi-Science Pub.

Title: Cure for the IKIA Syndrome : presented at IACRL 2008 conference: revised_assignment1for approval
Creator: Uth, Charles, Link, Jeanne
Date: 2008-02
Description: Informal observations of a practical and creative approach piloting Blended Library Instruction for undergraduate Civil Architecture and...
Show moreInformal observations of a practical and creative approach piloting Blended Library Instruction for undergraduate Civil Architecture and Engineering students, in collaboration with faculty. At Illinois Institute of Technology students don’t receive library instruction as a required class or in tandem with a composition class. Faculty will schedule one-time sessions, which ideally should be planned with a class assignment in mind, but students are rarely engaged with a one time instruction. Many have IKIA syndrome or I Know It Already syndrome. The Millennials are a group that has integrated technology into every aspect of their lives and they assume that retrieving useful or necessary information will be easy. When they discover this isn’t the case lack of time, heightened anxiety, and increased frustration can prevent them from doing their best work. By intentionally creating a similar crisis prior to library instruction, students were more interested in what they stood to gain during pending library instruction. In this presentation we will discuss: 1) A creative means of delivering library instruction to a traditionally challenging population: engineering undergraduate students 2) Qualitative information collected via multiple assignments and interpreted in a quantitative fashion, as well as our observations. 3) A method for preparing students for library instruction that can be applied in almost any discipline without asking the instructor to sacrifice class time.
Show less

Title: reVOLT: An Electric Vehicle Charging Station Prototype: Bristow_Abby_EVStation
Creator: Bristow, Abby
Date: 5/4/2011, 2011-05
Description: An electric vehicle charging station prototype. The project proposes coupling vehicle charging with other revenue generating program that...
Show moreAn electric vehicle charging station prototype. The project proposes coupling vehicle charging with other revenue generating program that grows and shrinks according to site restrictions. A small, medium, and large prototype are developed.
Show less

Title: Sloan Valve Company (sequence unknown), IPRO 306 - Deliverables
Creator: Delahanty, Sean, Jaouen, Julien, Thakkar, Hetul, Jones, Santiago Guerrero, Kim, Sung, Toor, Hammad, Jalan, Arjun, Soleja, Sikander, Zhang, Yayan
Date: 2009-12
Description: Sloan Valve manufactures and distributes commercial valves and plumbing fixtures globally. The IPRO team will work to improve the 'procure to...
Show moreSloan Valve manufactures and distributes commercial valves and plumbing fixtures globally. The IPRO team will work to improve the 'procure to pay' process and also assist in the development of a new warehouse management module.
Sponsorship: Sloan Valve Company
Deliverables for IPRO 306: Sloan Valve for the fall 2009 semester.
Show less

Title: ENABLING TOOLS FOR SINGLE CELL ANALYSIS
Creator: Li, Zhaoxia
Date: 2011-07, 2011-07
Description: Cells are basic functional units of life. A cell function is mediated by proteins and genes, whose distribution and expression level depends...
Show moreCells are basic functional units of life. A cell function is mediated by proteins and genes, whose distribution and expression level depends remarkably on the microenvironment. In the native environment, individual cells behave differently but communicate with surrounding cells. It is imperative to investigate proteins and genes at the single cell level in their native environment. The current representative single cell analysis methods, fluorescent techniques, are the most direct tools to study a single cell. The commonly used methods to measure protein and gene expression levels in single cells are on the basis of fluorescence labeling, such as fluorescence-activated cell sorting and live cell microscopy. They become more powerful when combine with the use of microfluidic devices. The disadvantages of these methods are, (1) their limited sensitivity doesn’t allow the detection of low-abundance proteins and genes; (2) they are unable to detect the cell-to-cell difference within a population; (3) the cell-sorting based method is lack of spatial resolution since the isolation of cells from the natural environment is required for analysis. To tackle these challenges, we established atomic force microscopy based approaches for in-situ gene and protein analysis on a target single live cell. The methods provide the spatial and quantitative information of cells in their native culture environment. They are effective and sensitive to detect low-abundant proteins and genes. In this thesis work, we developed a novel immunofluorescence assisted affinity mapping (IF-AM) method, in which immunofluorescence provides the guidance to locate a desired type of cell in a cell community for performing affinity mapping to quantify the local protein density at a high spatial resolution. Due to the ability of directly assessing proteins of individual cells, the IF-AM method is shown to be a sensitive tool for xiii resolving subtle differences in the local expression of membrane proteins even at low abundance. In the following work, we improved the accuracy of protein quantification by adapting the separation work based calculation rather than the previously used maximum adhesion force based calculation, and established a practical model to analyze the data systematically. We applied the methods to investigate the membrane proteins TRA-1-81 and E-cadherin on human embryonic stem cells. The heterogeneous distribution of TRA- 1-81 and the homogeneous distribution of E-cadherin as well as the quantitative measurement of the protein local abundance provided comprehensive information in understanding the strategy of hES cells to maintain the stemness during cell proliferation and to initiate the differentiation. An mRNA retrieval method was also developed to perform the gene expression analysis on a single cell of a desired type in a cell community. This was achieved by using a functionalized AFM tip as a bait to bind and retrieve mRNA from a desired single cell, followed by sensitive Quantitative Polymerase Chain Reaction (Q-PCR) analysis. The extraction of mRNA from live cells was performed with non/negligible damage to the cells. The established method here enabled the gene expression analysis of individual live cells at the original sites without disrupting the cell context. Thus the gene expression of a target cell and its surrounding cells can be analyzed in parallel, deriving concrete data for understanding the behavior of one cell in concert with that of the surrounding cells in the same or different cell population. The method was successfully applied in the study of side population cells in ovarian cancer cells. The methods developed in this thesis are versatile, and can be broadly applied to the study of different membrane proteins and genes of various cell types.
Ph.D. in Chemistry, July 2011
Show less

Title: Tungsten lamp as a secondary standard of light
Creator: Bremers, H. J., Jr., Chapman, A. J., Jr.
Date: 2009, 1910
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/tungstenlampasse00brem
Thesis (B.S.)--Armour Institute of Technology

Title: FORCED PERIODIC CONTROL OF AN EXOTHERMIC CSTR WITH MULTIPLE INPUT OSCILLATIONS
Creator: Rigopoulos, K., Shu, X. S., Cinar, A.
Date: 1988-12
Publisher: AMER INST CHEMICAL ENGINEERS
Description: Interaction among various oscillating inputs may result in significant modifications in the behavior of a system under forced periodic control...
Show moreInteraction among various oscillating inputs may result in significant modifications in the behavior of a system under forced periodic control. Forced oscillations in the input flow rate and input concentrations of an exothermic continuous stirred tank reactor enable the stabilized operation of the CSTR in the unstable steady state region. Reactor temperature oscillations under forced periodic control are similar to the oscillations resulting from proportional-integral feedback or nonlinear (push-pull) feedback control, and under some operating conditions the oscillation amplitude is significantly lower. Theoretical and experimental studies illustrate the effects of forcing frequency and phase shift on reactor behavior.
Endnote format citation
Show less

Title: PEGYLATION OF FIBRONECTIN AND ITS FUNCTIONAL DOMAINS: EFFECT ON STABILITY AND BIOLOGICAL ACTIVITY
Creator: Zhang, Chen
Date: 2013, 2013-07
Description: Delayed wound healing in many chronic wounds has been linked to the lack of extracellular matrix (ECM) support and the degradation of...
Show moreDelayed wound healing in many chronic wounds has been linked to the lack of extracellular matrix (ECM) support and the degradation of fibronectin (FN) by an abnormally high protease level. The ECM is important in wound healing because it provides physical and chemical cues that direct tissue growth and development. FN is a key ECM protein that attracts and binds different molecules and cells and thereby supports biological responses associated with wound healing. The goal of my study is two fold: (1) To create an ECM analogue based on a composite of polyethylene glycol (PEG) hydrogels and FN binding domains and (2) To stabilize FN against proteolytic degradation by conjugating it to PEG. To address the first goal, I used Michael addition chemistry to covalently link the cell-binding domain of FN, III9−10, to PEG diacrylate and cross-linked the conjugate to PEG hydrogels. The conjugation of PEG to III9−10 was through cysteines in the affinity tag Glutathione S Transferase (GST). The conjugate of GST-III9−10 and PEG was characterized by: (i) Circular dichroism studies to determine secondary structure, (ii) Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to determine molecular weight, and (iii) Ellmans reagent to determine the efficiency of PEG conjugation to GST-III9−10. The conjugate of PEG and GST-III9−10 had comparable secondary structure to GST-III9−10. SDS-PAGE studies showed that up to three PEG molecules were attached to one GST-III9−10 molecule. The efficiency of PEG conjugation was greater than 90% and occurred within 30 minutes after PEG diacrylate addition. Adhesion assays were used as a metric of biological activity. These assays demonstrated that on a molar basis cell adhesion and spreading were significantly higher on PEG hydrogels with GST-III9−10 than those with the commonly used arginine-glycine-aspartic acid (RGD) peptide. Scaffold rigidity is an important biological cues that influence xi cell responses. However, a comparative study of rigidity on GST-III9−10 and RGD functionalized PEG hydrogels demonstrated that differences in rigidity could not account for differences in cell adhesion and spreading between RGD and GST-III9−10 functionalized PEG hydrogels. Thus as ECM analogues, GST-III9−10 functionalized hydrogels provide more robust biochemical cues than RGD functionalized hydrogels. Studies of PEG hydrogel composites with mixtures of III9−10 and a fibronectin binding domain demonstrated that biological responses of adhesion and spreading and extracellular matrix assembly could be controlled by varying the ratio of these two domains and the rigidity of the PEG hydrogels. FN was stabilized against proteolytic degradation by covalent attaching it to PEG or by PEGylating it. FN was first isolated from human plasma by gelatin affinity chromatography and then PEGylated using two methods. The first method is to PEGylate human plasma fibronectin (HPFN) at cysteine residues with 3.4 kDa PEG diacrylate. The second method is to PEGylate HPFN at lysine residues on the surface with 2-10 kDa PEG Succinimidyl carboxy methyl esters. Cysteine PEGylation of HPFN was first carried out because cysteines are concentrated in the amino- terminus of HPFN which leaves two-thirds of the molecule, including the cell-binding domain, unperturbed. PEGylation of HPFN on cysteines resulted in a molecule that supported cell adhesion, spreading, focal adhesion formation and cell migration in a comparable manner to native HPFN. Moreover, PEGylated HPFN was incorporated into the ECM in a similar manner to native HPFN when present in the culture media but not when coated on a surface indicating that PEGylation on cysteines modified some biological activity of HPFN. Additionally, HPFN PEGylated by this manner could not bind denatured collagen or gelatin. The gelatin-binding domain is at the site of cysteine PEGylation. The second approach for PEGylation of HPFN was through lysine residues xii on the surface of the protein. This approach was used because it targeted different amino acid residues in FN. The length of PEG and extent of PEGylation have been reported to influence biological activity of proteins. In the second approach, both PEG length and extent were varied. HPFN completely PEGylated on lysines residues was significantly more proteolytically stable than native HPFN but had reduced cell attachment and spreading. Furthermore, cell spreading and attachment on surfaces conjugated with this lysine PEGylated HPFN decreased with increasing PEG length. Partially PEGylated HPFN was synthesized by masking the cell and gelatin binding domains during PEGylation. The partially PEGylated HPFN supported cell adhesion and spreading in a similar manner to native HPFN and was more proteolytically stable. For the partially PEGylated HPFN, the size of PEG poly had no significant influence on the attachment and spreading of cells. These studies are the first attempt by any laboratory to stabilize FN against proteolytic degradation while retaining activity and show the feasibility of this approach as a potential therapeutic approach. The work presented here shows a two-prong approach by which the problem of ECM degradation and deficiency chronic wound healing can be addressed. The first approach for addressing ECM deficiency is through a scaffold design methodology. The novelty of the scaffold approach is that it uses the cell-binding domains of FN instead of the often-used RGD peptide. I demonstrate that a PEG hydrogel with the cell-binding domain produces a more robust biological response in cells than a PEG hydrogel with the RGD peptide. I also demonstrate that varying different functional domains of fibronectin can be used to controllably stimulate multiple biological responses. The second approach demonstrates a method by which FN, a key ECM protein, is stabilized against proteolytic degradation without perturbing its activity. These studies of creating PEG-FN conjugates are the first of their kind. Collectively, the data that I present in this thesis will lead to novel therapeutic methods for treating chronic wounds.
PH.D in Chemical Engineering, December 2012
Show less

repository.iit

Search the repository

Pages

Pages

Enabled Filters

Refine Results

Type

Date

Academic status of creator

Department

Subject

Creator

Part of