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Georgia Tech
1.
Jones, Clinton D.
Poly(N-Isopropylacrylamide) based microgels :
I Fundamental properties of core/shell microgels II Assembly and photothermal patterning of microgel colloidal crystals.
Degree: PhD, Chemistry and biochemistry, 2003, Georgia Tech
URL: http://hdl.handle.net/1853/30355 
Subjects/Keywords: Colloids; Nanoparticles
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APA (6th Edition):
Jones, C. D. (2003). Poly(N-Isopropylacrylamide) based microgels :
I Fundamental properties of core/shell microgels II Assembly and photothermal patterning of microgel colloidal crystals. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/30355
Chicago Manual of Style (16th Edition):
Jones, Clinton D. “Poly(N-Isopropylacrylamide) based microgels :
I Fundamental properties of core/shell microgels II Assembly and photothermal patterning of microgel colloidal crystals.” 2003. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/30355.
MLA Handbook (7th Edition):
Jones, Clinton D. “Poly(N-Isopropylacrylamide) based microgels :
I Fundamental properties of core/shell microgels II Assembly and photothermal patterning of microgel colloidal crystals.” 2003. Web. 15 Jan 2021.
Vancouver:
Jones CD. Poly(N-Isopropylacrylamide) based microgels :
I Fundamental properties of core/shell microgels II Assembly and photothermal patterning of microgel colloidal crystals. [Internet] [Doctoral dissertation]. Georgia Tech; 2003. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/30355.
Council of Science Editors:
Jones CD. Poly(N-Isopropylacrylamide) based microgels :
I Fundamental properties of core/shell microgels II Assembly and photothermal patterning of microgel colloidal crystals. [Doctoral Dissertation]. Georgia Tech; 2003. Available from: http://hdl.handle.net/1853/30355
2.
Smith, Michael Hughes.
The design of multifunctional hydrogel nanoparticles for drug delivery.
Degree: PhD, Chemistry and Biochemistry, 2012, Georgia Tech
URL: http://hdl.handle.net/1853/43609
► Hydrogel micro- and nanoparticles (microgels and nanogels) are a promising class of drug delivery vehicles. Composed of hydrophilic polymers arranged into a cross-linked network structure,…
(more)
▼ Hydrogel micro- and nanoparticles (microgels and nanogels) are a promising class of drug delivery vehicles. Composed of hydrophilic polymers arranged into a cross-linked network structure, nanogels show several attractive features for the delivery of macromolecule therapeutics. For instance, the hydrated, porous internal cavity of the nanogel may serve as a high capacity compartment for loading macromolecules, whereas the periphery of the nanogel may be used as a scaffold for conjugating cell-specific targeting moieties. This dissertation presents recent investigations of nanogels as targeted delivery vehicles for oligonucleotides to cancer cells, while exploring new nanogel chemistries that enable future in vivo applications. For instance, synthetic efforts have produced particles capable of erosion into low molar mass constituents, providing a possible mechanism of particle clearance after repeated administration in vivo. In another example, the microgel network chemistry was tuned to promote the encapsulation of charged proteins. In parallel with those synthetic efforts, new light scattering methodologies were developed to accurately quantify the particle behaviors (e.g. loading, erosion). Using multiangle light scattering (MALS), changes in particle molar mass and radius were measured, providing a quantitative and direct approach for monitoring nanogel erosion and macromolecule encapsulation. The new particle chemistries demonstrated, together with enabling light scattering methods, will catalyze the development of improved delivery vehicles in the near future.
Advisors/Committee Members: Professor L. Andrew Lyon (Committee Chair), Professor Anselm Griffin (Committee Member), Professor Facundo Fernandez (Committee Member), Professor Jiri Janata (Committee Member), Professor Robert Dickson (Committee Member).
Subjects/Keywords: Light scattering; SiRNA; RNA interference; Microgel; Drug delivery; Hydrogel particle; Nanogel; Drug delivery systems; Nanogels; Colloids; Nanostructured materials
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APA (6th Edition):
Smith, M. H. (2012). The design of multifunctional hydrogel nanoparticles for drug delivery. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/43609
Chicago Manual of Style (16th Edition):
Smith, Michael Hughes. “The design of multifunctional hydrogel nanoparticles for drug delivery.” 2012. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/43609.
MLA Handbook (7th Edition):
Smith, Michael Hughes. “The design of multifunctional hydrogel nanoparticles for drug delivery.” 2012. Web. 15 Jan 2021.
Vancouver:
Smith MH. The design of multifunctional hydrogel nanoparticles for drug delivery. [Internet] [Doctoral dissertation]. Georgia Tech; 2012. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/43609.
Council of Science Editors:
Smith MH. The design of multifunctional hydrogel nanoparticles for drug delivery. [Doctoral Dissertation]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/43609
3.
Cho, Jae Kyu.
The dynamics and phase behavior of suspensions of stimuli-responsive colloids.
Degree: PhD, Chemical Engineering, 2009, Georgia Tech
URL: http://hdl.handle.net/1853/31682
► The studies of the dynamics, phase behavior, interparticle interactions, and hydrodynamics of stimuli-responsive pNIPAm-co-AAc microgels were described in this thesis. Due to their responsiveness to…
(more)
▼ The studies of the dynamics, phase behavior, interparticle interactions, and hydrodynamics of stimuli-responsive pNIPAm-co-AAc microgels were described in this thesis. Due to their responsiveness to external stimuli, these colloidal particles serve as excellent model systems to probe the relationship between colloidal interactions and phase behavior. As a first step, we established our core experimental methodology, by demonstrating that particle tracking video microscopy is an effective technique to quantify various parameters in colloidal systems. Then we used the technique in combination with a microfluidic device that provides in situ control over sample pH to probe the phase behavior of pNIPAm-co-AAc microgel suspensions. In essence, the experimental set-up enables changes in effective particle volume fractions by changing pH, which can be used to construct the phase diagram. In order to explain the unique features of the microgel phase diagram, we measured the underlying pairwise interparticle potential of pNIPAm-co-AAc microgels directly in quasi-2D suspension and proved that the interactions are pH dependent and can range from weakly attractive to soft repulsive. Finally, the hindered Brownian diffusion due of colloidal particles confined by hard walls was investigated systematically and striking differences between hard sphere and soft sphere were found, with soft pNIPAm-co-AAc microgels showing surprising mobility even under strong confinement.
Advisors/Committee Members: Victor Breedveld (Committee Chair), Eric W. Weeks (Committee Member), Hang Lu (Committee Member), J. Carson Meredith (Committee Member), L. Andrew Lyon (Committee Member).
Subjects/Keywords: Rheology; Microgel; Hydrogel; Polymer; Colloidal suspensions; Complex fluids; Van der Waals forces; Hydrodynamics; Brownian movements
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APA (6th Edition):
Cho, J. K. (2009). The dynamics and phase behavior of suspensions of stimuli-responsive colloids. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31682
Chicago Manual of Style (16th Edition):
Cho, Jae Kyu. “The dynamics and phase behavior of suspensions of stimuli-responsive colloids.” 2009. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/31682.
MLA Handbook (7th Edition):
Cho, Jae Kyu. “The dynamics and phase behavior of suspensions of stimuli-responsive colloids.” 2009. Web. 15 Jan 2021.
Vancouver:
Cho JK. The dynamics and phase behavior of suspensions of stimuli-responsive colloids. [Internet] [Doctoral dissertation]. Georgia Tech; 2009. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/31682.
Council of Science Editors:
Cho JK. The dynamics and phase behavior of suspensions of stimuli-responsive colloids. [Doctoral Dissertation]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/31682
4.
Lee, Jinhyun.
Development of an anisotropic swelling hydrogel for tissue expansion: control over the degree, rate and direction of hydrogel swelling.
Degree: PhD, Polymer, Textile and Fiber Engineering, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/31693
► Hydrogels are polymeric materials with chemically, physically or topologically crosslinked networks which have a capacity to absorb and retain water. They have been frequently used…
(more)
▼ Hydrogels are polymeric materials with chemically, physically or topologically crosslinked networks which have a capacity to absorb and retain water. They have been frequently used for many medical applications because of their useful physical properties such as oxygen permeability and excellent compatibility with living tissue and blood. The long term goal of this research is to develop a hydrogel system for potential use in reconstructive and plastic surgeries such as the closure of cleft palate defects and syndactyly (congenitally fused fingers or toes) repair. The medical requirements for such systems are not only a high degree of swelling, but also slow swelling rate, preferred direction of swelling (anisotropic swelling), appropriate mechanical strength, in addition to being biocompatible. A large degree of swelling would limit the number of surgical procedures required thereby reducing the cost and risk of surgery. A slow swelling rate can avoid tissue necrosis and help tissue growth during the tissue expansion process. Anisotropic swelling is required for specific surgical applications such as cleft palate repairs.
Known to be biocompatible hydrogel systems, of a neutral gel system consisting of N-vinyl-2-pyrrolidinone (VP) and 2-hydroxyethyl methacrylate (HEMA) copolymers and an ionizable gel system of VP and acrylic acid (AA) copolymers were prepared using thermal and controlled UV-initiated polymerization. Using these VP/HEMA and VP/AA gel systems, various approaches to control their degree and rate of swelling were studied as a function of key controllable parameters. Their mechanical properties and structural characteristics determining their swelling behavior and mechanical properties also were investigated. Through these studies, how to control the key parameters that affect such swelling behavior was understood in addition to optimizing the gel systems for large degree of swelling, slow swelling rate, and mechanical integrity. Investigations into a number of methods to control the swelling rate were also undertaken for different VP/HEMA based gel systems. Multilayers of alternating gels and elastomer films (polybutadiene (PB) or polydimethylsiloxane (PDMS)) as well as gels encapsulated with the elastomer films were prepared. In addition, gels were prepared with inclusion of either silver nanoparticles or methacrylates with increasing the length of hydrophobic groups for the studies of swelling rate.
In this work, two novel methods to control swelling direction (anisotropic swelling) of hydrogels were investigated. One method induces anisotropic swelling through structural gradients within the VP/HEMA gels synthesized by UV polymerization using gradient photomasks. A more promising method used stress induced anisotropic swelling for compressed VP/AA gels. The morphology-gradient VP/HEMA hydrogel system did not show large scale anisotropic swelling. However, the compressed VP/AA gels produced significant anisotropic swelling due to the controlled anisotropy of network…
Advisors/Committee Members: David G. Bucknall (Committee Chair), Haskell W. Beckham (Committee Member), L. Andrew Lyon (Committee Member), Yadong Wang (Committee Member), Yonathan Thio (Committee Member).
Subjects/Keywords: Anisotropic swelling; Hydrogel; Swelling; Tissue expansion; Swelling rate; Degree of swelling; Swelling direction; Colloids Absorption and adsorption; Tissue engineering
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APA (6th Edition):
Lee, J. (2008). Development of an anisotropic swelling hydrogel for tissue expansion: control over the degree, rate and direction of hydrogel swelling. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31693
Chicago Manual of Style (16th Edition):
Lee, Jinhyun. “Development of an anisotropic swelling hydrogel for tissue expansion: control over the degree, rate and direction of hydrogel swelling.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/31693.
MLA Handbook (7th Edition):
Lee, Jinhyun. “Development of an anisotropic swelling hydrogel for tissue expansion: control over the degree, rate and direction of hydrogel swelling.” 2008. Web. 15 Jan 2021.
Vancouver:
Lee J. Development of an anisotropic swelling hydrogel for tissue expansion: control over the degree, rate and direction of hydrogel swelling. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/31693.
Council of Science Editors:
Lee J. Development of an anisotropic swelling hydrogel for tissue expansion: control over the degree, rate and direction of hydrogel swelling. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/31693
5.
Choi, Sungmoon.
Fluorescent noble metal nanodots for biological applications.
Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/37195
► Commercial organic dyes are widely used for cellular staining due to their small size, high brightness, and chemical functionality. However, their blinking and photobleaching are…
(more)
▼ Commercial organic dyes are widely used for cellular staining due to their small size, high brightness, and chemical functionality. However, their blinking and photobleaching are not ideal for studying dynamics inside live cells. An improvement over organics and much larger quantum dots, silver nanodots (Ag NDs) exhibit low cytotoxicity and excellent brightness and photostability, while retaining small size. We have utilized ssDNA hairpin structures to encapsulate Ag NDs with excellent spectral purity, high concentration, and good chemical and photophysical stability in a variety of biological media. Multi-color staining of fixed and live cells has been achieved, suggesting the promise of Ag NDs as good fluorophores for intracellular imaging. The great brightness and photostability of Ag nanodots indicate that they might be outstanding imaging agents for in vivo studies when encapsulated in delivery vehicles. In addition, Ag NDs can be optically modulated, resulting in increased sensitivity within high backgrounds. These good characteristics are combined with delivery vehicles such as PLGA and nanogels. After encapsulation, Ag nanodots still retain their good photophysical properties and modulation. It might be useful for in vivo applications in the near future
Advisors/Committee Members: Robert M. Dickson (Committee Chair), Christoph Fahrni (Committee Member), L. Andrew Lyon (Committee Member), Mostafa A. El-Sayed (Committee Member), Niren Murthy (Committee Member).
Subjects/Keywords: DNA; Nanodots; Drug delivery; Cellular staining; Fluorophores; Silver; Drug delivery systems; Biomedical materials Imaging compatibility; Diagnostic imaging
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APA (6th Edition):
Choi, S. (2010). Fluorescent noble metal nanodots for biological applications. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/37195
Chicago Manual of Style (16th Edition):
Choi, Sungmoon. “Fluorescent noble metal nanodots for biological applications.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/37195.
MLA Handbook (7th Edition):
Choi, Sungmoon. “Fluorescent noble metal nanodots for biological applications.” 2010. Web. 15 Jan 2021.
Vancouver:
Choi S. Fluorescent noble metal nanodots for biological applications. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/37195.
Council of Science Editors:
Choi S. Fluorescent noble metal nanodots for biological applications. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/37195
Georgia Tech
6.
Heintz, Eva Liang-Huang.
Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles.
Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/4944
► Surface Biological Modification and Cellular Interactions of Magnetic Spinel Nanoparticles Eva Liang-Huang Heintz 191 Pages Directed by Dr. Z. John Zhang The interest in magnetic…
(more)
▼ Surface Biological Modification and Cellular Interactions of Magnetic Spinel Nanoparticles
Eva Liang-Huang Heintz
191 Pages
Directed by Dr. Z. John Zhang
The interest in magnetic nanoparticles is multi-dimensional. Fundamentally, it is important to be able to control their magnetic properties and to correlate to specific applications. In biology, magnetic nanoparticles offer promising potential as magnetic carriers or chaperones for magnetic localization and manipulation of therapeutic reagents.
The synthesis of superparamagnetic CoFe2-xSmxO4 nanoparticles and the tunability of their magnetic properties by size and composition variations are discussed. An increase in size of CoSm0.19Fe1.81O4 nanoparticles produced an increase in blocking temperature and saturation magnetization, but a non-linear coercitivity response was observed with change in size. By varying the composition, the saturation magnetization of CoFe2-xSmxO4 decreased dramatically while the coercitivity increased when compared to native cobalt spinel ferrite (CoFe2O4) nanoparticles. These results demonstrate how the magnetic properties of cobalt spinel ferrite nanoparticles can be tailored to specific applications.
Surface modifications of cobalt spinel ferrite nanoparticles facilitated the conjugation of oligonucleotides. Using a transfection reagent, CoFe2O4 ??igonucleotide conjugates were delivered into mammalian cells. Post transfection, synchronized movement of cells in response to an external magnetic field was observed. This demonstrated the possibility of magnetic manipulation and localization of therapeutic reagents coupled to CoFe2O4 magnetic nanoparticles.
Results from this thesis demonstrate the potential role of magnetic spinel nanoparticles in cell biology and will facilitate the progress towards in vivo testing.
Advisors/Committee Members: Dr. Z. John Zhang (Committee Chair), Dr. Christopher Jones (Committee Member), Dr. Jiri Janata (Committee Member), Dr. L. Andrew Lyon (Committee Member), Dr. Laren Tolbert (Committee Member).
Subjects/Keywords: Magnetic nanoparticles; Spinel ferrite; Transfection; Magnetic manipulation; Samarium; Surface modification
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APA (6th Edition):
Heintz, E. L. (2004). Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/4944
Chicago Manual of Style (16th Edition):
Heintz, Eva Liang-Huang. “Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/4944.
MLA Handbook (7th Edition):
Heintz, Eva Liang-Huang. “Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles.” 2004. Web. 15 Jan 2021.
Vancouver:
Heintz EL. Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/4944.
Council of Science Editors:
Heintz EL. Surface Biological Modification and Cellular Interactions of Magnetic Spinel Ferrite Nanoparticles. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/4944
Georgia Tech
7.
Gadsby, Elizabeth Deibler.
Drug/DNA Interactions and Condensation
Investigated with Atomic Force Microscopy.
Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/5113
► Atomic force microscopy (AFM) is a particularly useful tool, for obtaining structural information about drug-nucleic acid interactions. The mode of drug binding intercalation versus groove…
(more)
▼ Atomic force microscopy (AFM) is a particularly useful tool, for obtaining structural information about drug-nucleic acid interactions. The mode of drug binding intercalation versus groove binding can be determined from images acquired on individual DNA molecules as the length of a DNA molecule increases in direct proportion to the number of intercalators bound to it.
The efforts of this research were directed toward elucidating the mode of binding of a series of drugs based on polymers of naphthalenetetracarboxyl diimide (NDI) interacting with a linearized DNA plasmid. During the course of the investigation of these drugs, DNA intercalation was confirmed as the mode of binding and the binding affinity estimated. Unexpectedly, concentration-dependent formation of secondary DNA structures including condensates was observed. DNA toroids, spheres, and rods were imaged and measured. Conformations that are believed to be intermediate condensate forms were also identified at lower poly-NDI concentrations. Models for the DNA condensation process have been proposed.
Ultimately, this research furthers the understanding of DNA condensation which can be applied to gene delivery systems and anti-viral agents. It may also help direct the development of better drugs based on the insight of poly-intercalators interactions with DNA.
Advisors/Committee Members: Lawrence A. Bottomley (Committee Chair), L. Andrew Lyon (Committee Member), Loren D. Williams (Committee Member), Nicholas V. Hud (Committee Member), William D. Hunt (Committee Member).
Subjects/Keywords: Atomic force microscopy; DNA; Condensation; Intercalation; Drug interaction
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APA (6th Edition):
Gadsby, E. D. (2004). Drug/DNA Interactions and Condensation
Investigated with Atomic Force Microscopy. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/5113
Chicago Manual of Style (16th Edition):
Gadsby, Elizabeth Deibler. “Drug/DNA Interactions and Condensation
Investigated with Atomic Force Microscopy.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/5113.
MLA Handbook (7th Edition):
Gadsby, Elizabeth Deibler. “Drug/DNA Interactions and Condensation
Investigated with Atomic Force Microscopy.” 2004. Web. 15 Jan 2021.
Vancouver:
Gadsby ED. Drug/DNA Interactions and Condensation
Investigated with Atomic Force Microscopy. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/5113.
Council of Science Editors:
Gadsby ED. Drug/DNA Interactions and Condensation
Investigated with Atomic Force Microscopy. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/5113
Georgia Tech
8.
Capadona, Lynn A.
Photoactivated Fluorescence from Small Silver Nanoclusters and Their Relation to Raman Spectroscopy.
Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/5117
► Photoactivated fluorescence from individual silver nanoclusters ranging in size from 2 8 atoms has been demonstrated at room temperature. The optical properties of such clusters…
(more)
▼ Photoactivated fluorescence from individual silver nanoclusters ranging in size from 2 8 atoms has been demonstrated at room temperature. The optical properties of such clusters are far superior to those of fluorescence dyes with absorption cross sections ~50 times stronger than those of even the best organic dyes. The strong oscillator strengths produced from such nanoclusters has been shown to yield comparable enhancement factors in the surface-enhanced Raman spectroscopy (SERS) process to those observed in the presence of a plasmon- supporting nanoparticle. Raman transitions are in fact so strong that antistokes scattering is also observable on a single molecule (SM) level marking the first true demonstration of SM-SERS to date. Capable of generating true scaffold specific Raman scattering on the single molecule level, the combination of fluorescence from the small nanoclusters and strong observed Raman signals in the absence of a nanoparticle strongly indicate a chemical or charge transfer SERS enhancement mechanism.
Advisors/Committee Members: Robert M. Dickson (Committee Chair), L. Andrew Lyon (Committee Member), Mohan Srinivasarao (Committee Member), Mostafa A. El-Sayed (Committee Member), Robert L. Whetten (Committee Member).
Subjects/Keywords: Data storage; Silver nanoclusters; Single molecule Raman
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APA (6th Edition):
Capadona, L. A. (2004). Photoactivated Fluorescence from Small Silver Nanoclusters and Their Relation to Raman Spectroscopy. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/5117
Chicago Manual of Style (16th Edition):
Capadona, Lynn A. “Photoactivated Fluorescence from Small Silver Nanoclusters and Their Relation to Raman Spectroscopy.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/5117.
MLA Handbook (7th Edition):
Capadona, Lynn A. “Photoactivated Fluorescence from Small Silver Nanoclusters and Their Relation to Raman Spectroscopy.” 2004. Web. 15 Jan 2021.
Vancouver:
Capadona LA. Photoactivated Fluorescence from Small Silver Nanoclusters and Their Relation to Raman Spectroscopy. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/5117.
Council of Science Editors:
Capadona LA. Photoactivated Fluorescence from Small Silver Nanoclusters and Their Relation to Raman Spectroscopy. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/5117
Georgia Tech
9.
Conwell, Christine C.
Kinetic and Thermodynamic Factors Govern DNA Condensate Size and Morphology.
Degree: PhD, Chemistry and Biochemistry, 2004, Georgia Tech
URL: http://hdl.handle.net/1853/5213
► It is well known that multivalent cations can cause DNA to condense from solution to form high-density nanometer scale particles. However, several fundamental questions concerning…
(more)
▼ It is well known that multivalent cations can cause DNA to condense from solution to form high-density nanometer scale particles. However, several fundamental questions concerning the phenomenon of DNA condensation remain unanswered. DNA condensation in vitro has been of interest for many years as a model of naturally occurring DNA packaging (e.g. chromatin, sperm head and virus capsid packing). More recently, DNA condensation has been of interest in optimizing artificial gene delivery, where packaging genes to an optimal size is essential to developing efficient uptake and delivery systems. The research presented in this dissertation provides an in depth biophysical study of the factors that control DNA condensate size and morphology. Millimolar changes in the ionic strength of the solution were found to alter the size of toroidal condensates. Variations in the order of addition of the counterions also significantly changed the size and morphology of the condensates. Studies were also performed to investigate the effects of static curvature and increased DNA flexibility on DNA condensation. These include the addition of static bending by sequence directed curvature, dynamic bending through protein-DNA interactions and reducing DNA persistence length by condensing single-stranded DNA. Several new models of DNA condensation are proposed based on the experimental data presented in this thesis.
Advisors/Committee Members: Nicholas V. Hud (Committee Chair), James C. Powers (Committee Member), L. Andrew Lyon (Committee Member), Loren D. Williams (Committee Member), Mark R. Prausnitz (Committee Member).
Subjects/Keywords: Gene delivery; Toroids; Condensation; DNA
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APA (6th Edition):
Conwell, C. C. (2004). Kinetic and Thermodynamic Factors Govern DNA Condensate Size and Morphology. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/5213
Chicago Manual of Style (16th Edition):
Conwell, Christine C. “Kinetic and Thermodynamic Factors Govern DNA Condensate Size and Morphology.” 2004. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/5213.
MLA Handbook (7th Edition):
Conwell, Christine C. “Kinetic and Thermodynamic Factors Govern DNA Condensate Size and Morphology.” 2004. Web. 15 Jan 2021.
Vancouver:
Conwell CC. Kinetic and Thermodynamic Factors Govern DNA Condensate Size and Morphology. [Internet] [Doctoral dissertation]. Georgia Tech; 2004. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/5213.
Council of Science Editors:
Conwell CC. Kinetic and Thermodynamic Factors Govern DNA Condensate Size and Morphology. [Doctoral Dissertation]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/5213
Georgia Tech
10.
Nayak, Satish Prakash.
Design, Synthesis and Characterization of Multiresponsive Microgels.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/6845
► This thesis is geared towards using hydrogel nanoparticles in various biotechnological applications. The polymer that was used in making these nanoparticles was poly(N-isopropylacrylamide), which is…
(more)
▼ This thesis is geared towards using hydrogel nanoparticles in various biotechnological applications. The polymer that was used in making these nanoparticles was poly(N-isopropylacrylamide), which is a thermoresponsive polymer. These particles were used in making fast responsive polymer films, which can be used in optics. It was observed that the rate of deswelling increased as the concentration of the nanoparticles in the film was increased. These particles were also used in making photoresponsive materials. In this case a photoresponsive dye (malachite green) was conjugated to these nanoparticles and in presence of light of appropriate wavelength the particles undergo a phase transition. A core/shell construct was synthesized where the core was composed of degradable cross-links and the shell of composed of non-degradable cross-links. The degradable cross-linker had vicinal diols, which can be cleaved by sodium periodate. Hence after degrading the core, hollow particles were obtained. Zwitterionic particles were made by incorporating a cationic and anionic comonomer. These microgels go from a positively charged state to zwitterionic to negatively charged state on increasing the pH. One of the important potential applications for these microgels is drug delivery. Microgels were used for targeting cancer cells. Folic acid was used as the targeting ligand. The microgels were conjugated with folic acid and were able to target cells that overexpress folate receptors. In one other application core/shell microgels were made which exhibit pore-size dependent permeation of proteins.
Advisors/Committee Members: Dr. L. Andrew Lyon (Committee Chair), Dr. Christopher W. Jones (Committee Member), Dr. Jiri Janata (Committee Member), Dr. Marcus Weck (Committee Member), Dr. Nicholas V. Hud (Committee Member).
Subjects/Keywords: pNIPAm; Core/Shell; Nanoparticles; Hydrogels; Polymers; Thin films; Polymers Thermal properties; Polymers Optical properties; Nanoparticles Synthesis; Colloids
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APA (6th Edition):
Nayak, S. P. (2005). Design, Synthesis and Characterization of Multiresponsive Microgels. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6845
Chicago Manual of Style (16th Edition):
Nayak, Satish Prakash. “Design, Synthesis and Characterization of Multiresponsive Microgels.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/6845.
MLA Handbook (7th Edition):
Nayak, Satish Prakash. “Design, Synthesis and Characterization of Multiresponsive Microgels.” 2005. Web. 15 Jan 2021.
Vancouver:
Nayak SP. Design, Synthesis and Characterization of Multiresponsive Microgels. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/6845.
Council of Science Editors:
Nayak SP. Design, Synthesis and Characterization of Multiresponsive Microgels. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6845
Georgia Tech
11.
Varga, Tamas.
Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/6905
► Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials Tamas Varga 370 pages Directed by Dr. Angus P. Wilkinson The high-pressure behavior of…
(more)
▼ Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials
Tamas Varga
370 pages
Directed by Dr. Angus P. Wilkinson
The high-pressure behavior of several negative thermal expansion materials was studied by different methods. In-situ high-pressure x-ray and neutron diffraction studies on several compounds of the orthorhombic Sc2W3O12 structure revealed an unusual bulk modulus collapse at the orthorhombic to monoclinic phase transition. In some members of the A2M3O12 family, a second phase transition and/or pressure-induced amorphization were also seen at higher pressure. The mechanism for volume contraction on compression is different from that on heating.
A combined in-situ high pressure x-ray diffraction and absorption spectroscopic study has been carried out for the first time. The pressure-induced amorphization in cubic ZrW2O8 and ZrMo2O8 was studied by following the changes in the local coordination environments of the metals. A significant change in the average tungsten coordination was found in ZrW2O8, and a less pronounced change in the molybdenum coordination in ZrMo2O8 on amorphization. A kinetically frustrated phase transition to a high-pressure crystalline phase or a kinetically hindered decomposition, are likely driving forces of the amorphization. A complementary ex-situ study confirmed the greater distortion of the framework tetrahedra in ZrW2O8, and revealed a similar distortion of the octahedra in both compounds.
The possibility of stabilizing the low thermal expansion high-temperature structure in AM2O7 compounds to lower temperatures through stuffing of ZrP2O7 was explored. Although the phase transition temperature was suppressed in MIxZr1-xMIIIxP2O7 compositions, the chemical modification employed was not successful in stabilizing the high-temperature structure to around room temperature.
An attempt has been made to control the thermal expansion properties in materials of the (MIII0.5MV0.5)P2O7-type through the choice of the metal cations and through manipulating the ordering of the cations by different heat treatment conditions. Although controlled heat treatment resulted in only short-range cation ordering, the choice of the MIII cation had a marked effect on the thermal expansion behavior of the materials.
Different grades of fluorinert were examined as pressure-transmitting media for high-pressure diffraction studies. All of the fluorinerts studied became nonhydrostatic at relatively low pressures (~1 GPa).
Advisors/Committee Members: Dr. Angus P. Wilkinson (Committee Chair), Dr. Jiri Janata (Committee Member), Dr. L. Andrew Lyon (Committee Member), Dr. Meilin Liu (Committee Member), Dr. Z. John Zhang (Committee Member).
Subjects/Keywords: Negative thermal expansion; High pressure; X-ray diffraction; X-ray absorption spectroscopy; Pressure-induced amorphization; Thermal behavior; Expansion (Heat); Materials Thermal properties; Cations
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APA (6th Edition):
Varga, T. (2005). Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6905
Chicago Manual of Style (16th Edition):
Varga, Tamas. “Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/6905.
MLA Handbook (7th Edition):
Varga, Tamas. “Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials.” 2005. Web. 15 Jan 2021.
Vancouver:
Varga T. Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/6905.
Council of Science Editors:
Varga T. Synthesis and Characterization of Some Low and Negative Thermal Expansion Materials. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6905
Georgia Tech
12.
Marotta, Nicole Ella.
Patterned nanoarray sers substrates for pathogen detection.
Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/37274
► The objectives of the work presented were to 1) fabricate reproducible nanorod array SERS substrates, 2) detection of bacteria using nanorod substrates, 3) detection of…
(more)
▼ The objectives of the work presented were to 1) fabricate reproducible nanorod array SERS substrates, 2) detection of bacteria using nanorod substrates, 3) detection of DNA hybridization using nanorod substrates and 4) critically evaluate the sensing method.
Important findings from this work are as follows. A novel method for batch fabrication of substrates for surface enhanced Raman scattering (SERS) has been developed using a modified platen machined to fit in a commercial electron beam evaporator. The use of this holder enables simultaneous deposition of silver nanorod (AgNR) arrays onto six microscope slide substrates utilizing glancing angle deposition. In addition to multiple substrate fabrication, patterning of the AgNR substrates with 36 wells allows for physical isolation of low volume samples. The well-to-well, slide-to-slide, and batch-to-batch variability in both physical characteristics and SERS response of substrates prepared via this method was nominal. A critical issue in the continued development of AgNR substrates is their stability over time, and the potential impact on the SERS response. The thermal stability of the arrays was investigated and changes in surface morphology were evaluated using scanning electron microscopy and x-ray diffraction and correlated with changes in SERS enhancement. The findings suggest that the shelf-life of AgNR arrays is limited by migration of silver on the surface. Continued characterization of the AgNR arrays was carried out using fluorescent polystyrene microspheres of two different sizes. Theory suggests that enhancement between nanorods would be significantly greater than at the tops due to contributing electromagnetic fields from each nanostructure. In contrast to the theory, SERS response of microspheres confined to the tops of the AgNR array was significantly greater than that for beads located within the array. The location of the microspheres was established using optical fluorescence and scanning electron microscopy.
The application of SERS to characterizing pathogens such as bacteria and viruses is an active area of investigation. AgNR array-based SERS substrates have enabled detection of pathogens present in biofluids. Specifically, several publications have focused on determining the spectral bands characteristic of bacteria from different species and cell lines. Studies were carried out on three strains of bacteria as well as the medium in which the bacteria were grown. The spectra of the bacteria and medium were surprisingly similar, so additional spectra were acquired for commonly used bacterial growth media. In many instances, these spectra were similar to published spectra purportedly characteristic of specific bacterial species.
In addition to bacterial samples, nucleic acid hybridization assays were investigated. Oligonucleotide pairs specifically designed to detect respiratory syncytial virus (RSV) in nasal fluids were prepared and evaluated. SERS spectra acquired on oligos, alone or in combination, contain the…
Advisors/Committee Members: Lawrence Bottomley (Committee Chair), Julia Kubanek (Committee Member), L. Andrew Lyon (Committee Member), Loren Williams (Committee Member), Mostafa El-Sayed (Committee Member).
Subjects/Keywords: Silver nanostructure; Surface enhanced Raman scattering; Silver nanorod array; Surface enhanced Raman spectroscopy; Oblique angle deposition; Glancing angle deposition; SERS substrate; Raman effect; Raman spectroscopy
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APA (6th Edition):
Marotta, N. E. (2010). Patterned nanoarray sers substrates for pathogen detection. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/37274
Chicago Manual of Style (16th Edition):
Marotta, Nicole Ella. “Patterned nanoarray sers substrates for pathogen detection.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/37274.
MLA Handbook (7th Edition):
Marotta, Nicole Ella. “Patterned nanoarray sers substrates for pathogen detection.” 2010. Web. 15 Jan 2021.
Vancouver:
Marotta NE. Patterned nanoarray sers substrates for pathogen detection. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/37274.
Council of Science Editors:
Marotta NE. Patterned nanoarray sers substrates for pathogen detection. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/37274
Georgia Tech
13.
Sato, Jun.
Transient Rheology of Stimuli Responsive Hydrogels: Integrating Microrheology and Microfluidics.
Degree: PhD, Chemical Engineering, 2006, Georgia Tech
URL: http://hdl.handle.net/1853/14044
► A new microrheology set-up is described, which allows us to quantitatively measure the transient rheological properties and microstructure of a variety of solvent-responsive complex fluids.…
(more)
▼ A new microrheology set-up is described, which allows us to quantitatively measure the transient rheological properties and microstructure of a variety of solvent-responsive complex fluids. The device was constructed by integrating particle tracking microrheology and microfluidics and offers unique experimental capabilities for performing solvent-response measurements on soft fragile materials without applying external shear forces. Transient analysis methods to quantitatively obtain rheological properties were also constructed, and guidelines for the trade-off between statistical validity and temporal resolution were developed to accurately capture physical transitions. With the new device and methodology, we successfully quantified the transient rheological and microstructural responses during gel formation and break-up, and viscosity changes of solvent-responsive complex fluids. The analysis method was expanded for heterogeneous samples, incorporating methods to quantify the microrheology of samples with broad distributions of individual particle dynamics. Transient microrheology measurements of fragile, heterogeneous, self-assembled block copolypeptide hydrogels revealed that solvent exchange via convective mixing and dialysis can lead to significantly different gel properties and that commonly applied sample preparation protocols for the characterization of soft biomaterials could lead to erroneous conclusions about microstructural dynamics. Systematic investigations by varying key parameters, like molecular structure, gel concentration, salt concentration, and tracer particle size for microrheology, revealed that subtle variations in molecular architecture can cause major structural and microrheological changes in response dynamics. Moreover, the results showed that the method can be applied for studying gel formation and breakup kinetics. The research in this thesis facilitates the design of solvent-responsive soft materials with appropriate microstructural dynamics for in vivo applications like tissue engineering and drug delivery, and can also be applied to study the effect of solvents on self-assembly mechanisms in other responsive soft materials, such as polymer solutions and colloidal dispersions.
Advisors/Committee Members: Victor Breedveld (Committee Chair), Andreas S. Bommarius (Committee Member), J. Carson Meredith (Committee Member), L. Andrew Lyon (Committee Member), William J. Koros (Committee Member).
Subjects/Keywords: Complex fluids; Microrheology; Microfluidics; Stimuli-responsive; Transients (Dynamics); Smart materials; Rheology; Microfluidics; Complex fluids Analysis; Colloids
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APA (6th Edition):
Sato, J. (2006). Transient Rheology of Stimuli Responsive Hydrogels: Integrating Microrheology and Microfluidics. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/14044
Chicago Manual of Style (16th Edition):
Sato, Jun. “Transient Rheology of Stimuli Responsive Hydrogels: Integrating Microrheology and Microfluidics.” 2006. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/14044.
MLA Handbook (7th Edition):
Sato, Jun. “Transient Rheology of Stimuli Responsive Hydrogels: Integrating Microrheology and Microfluidics.” 2006. Web. 15 Jan 2021.
Vancouver:
Sato J. Transient Rheology of Stimuli Responsive Hydrogels: Integrating Microrheology and Microfluidics. [Internet] [Doctoral dissertation]. Georgia Tech; 2006. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/14044.
Council of Science Editors:
Sato J. Transient Rheology of Stimuli Responsive Hydrogels: Integrating Microrheology and Microfluidics. [Doctoral Dissertation]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/14044
Georgia Tech
14.
McGrath, Jonathan G.
Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials.
Degree: PhD, Chemistry and Biochemistry, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/14537
► This dissertation describes the use of spherical micro- and nanoparticles as building blocks for the fabrication of colloidal crystals. The polymer component used in all…
(more)
▼ This dissertation describes the use of spherical micro- and nanoparticles as building blocks for the fabrication of colloidal crystals. The polymer component used in all of the projects that are described herein is poly-N-isopropylacrylamide (pNIPAm). The polymeric identity of particles composed of this soft, hydrogel material, which is also thermoresponsive, contributes to particle self-assembly to form ordered structures. Specifically, particles that possess a core/shell topology were investigated to allow for the localization of distinct polymeric properties. Chapter 2 examines a characterization technique using fluorescence resonance energy transfer (FRET) that was explored to investigate the structure of pNIPAm particles that possess this core/shell topology. Chapters 4-6 investigate strategies to impart both stability and flexibility to the particles so that these properties could assist in particle self-assembly as well as provide a stable construct for the production of robust crystalline materials. Styrene was used as the main monomer component in a copolymer synthesis with NIPAm to achieve poly(styrene-co-N-isopropylacrylamide particles (pS-co-NIPAm) that exhibited both hard and soft properties. Simple drying procedures were used to form crystal assemblies with these particles and the application of these pS-co-NIPAm particle suspensions as processable, photonic inks is also investigated. Chapter 7 examines the ability to physically cross-link colloidal crystals composed of pS-co-NIPAm particles by simple heating methods to produce robust films. The optical properties of these crystal films could be tuned by simple rehydration of the film due to the hydrogel character of the crystal building blocks. Chapters 3 and 5 examine the synthesis and self-assembly strategies of core/shell particles using the properties of pNIPAm shell layers that have been added to different types of core particles (silver or pS-co-NIPAm) for the purposes of fabricating colloidal crystals with enhanced properties using thermal annealing procedures. Chapter 8 explores the use of silver particles as tracers for the characterization of colloidal crystals composed of thermally annealed colloidal crystals composed of pNIPAm hydrogel particles.
Advisors/Committee Members: Dr. L. Andrew Lyon (Committee Chair), Dr. Boris Mizaikoff (Committee Member), Dr. Facundo Fernandez (Committee Member), Dr. Jiri Janata (Committee Member), Dr. Victor Breedveld (Committee Member).
Subjects/Keywords: Colloidal crystal; Core/Shell; Nanoparticles; Microparticles; Ink; N-isopropylacrylamide; Nanoparticles; Colloidal crystals Synthesis; Colloidal crystals Structure
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APA (6th Edition):
McGrath, J. G. (2007). Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/14537
Chicago Manual of Style (16th Edition):
McGrath, Jonathan G. “Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials.” 2007. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/14537.
MLA Handbook (7th Edition):
McGrath, Jonathan G. “Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials.” 2007. Web. 15 Jan 2021.
Vancouver:
McGrath JG. Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/14537.
Council of Science Editors:
McGrath JG. Synthesis and Characterization of Core/Shell Hydrogel Nanoparticles and Their Application to Colloidal Crystal Optical Materials. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/14537
Georgia Tech
15.
Debord, Saet Byul.
Phase Behavior of Multiresponsive Microgel Dispersions.
Degree: PhD, Chemistry and Biochemistry, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/10458
► We present the phase behavior of soft sphere colloidal dispersions. The pH responsive and thermoresponsive microgels, poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAm-co-AAc), were used as a new building…
(more)
▼ We present the phase behavior of soft sphere colloidal dispersions. The pH responsive and thermoresponsive microgels, poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAm-co-AAc), were used as a new building block of colloidal crystals. The phase behavior of microgel dispersions was studied by different methods such as optical microscopy, particle trajectories, mean squared displacement (MSD) vs. lag time plots and radial distribution function. The results show that the phase of the sample relies on the particle concentration for dispersions of the same pH. As the pH approaches the pKa of microgels, the microgel dispersions show unusual crystalline phase at lower effective volume fraction than hard sphere melting transition. Also, at this pH regime, the microgel dispersions undergo slow and spatially heterogeneous crystal growth. The cooperative multi-body type attractive forces were proposed to explain the unusual stability at low effective volume fraction. Ion-dipole interactions were proposed to be the origin of the attractive forces. The melting point of bulk crystals at this pH regime is much higher than the volume phase transition temperature of the building block. These results are supportive of the attractive forces hypothesis.
Advisors/Committee Members: L. Andrew Lyon (Committee Chair), Marcus Weck (Committee Member), Mohan Srinivasarao (Committee Member), Thomas Orlando (Committee Member), Victor Breedveld (Committee Member).
Subjects/Keywords: Effective volume fraction; Attractive interacion; Soft interaction potential; Microgel dispersions; Phase behavior
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APA (6th Edition):
Debord, S. B. (2005). Phase Behavior of Multiresponsive Microgel Dispersions. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/10458
Chicago Manual of Style (16th Edition):
Debord, Saet Byul. “Phase Behavior of Multiresponsive Microgel Dispersions.” 2005. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/10458.
MLA Handbook (7th Edition):
Debord, Saet Byul. “Phase Behavior of Multiresponsive Microgel Dispersions.” 2005. Web. 15 Jan 2021.
Vancouver:
Debord SB. Phase Behavior of Multiresponsive Microgel Dispersions. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/10458.
Council of Science Editors:
Debord SB. Phase Behavior of Multiresponsive Microgel Dispersions. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/10458
Georgia Tech
16.
Singh, Neetu.
Synthetic routes to new core/shell nanogels:design and application in biomaterials.
Degree: PhD, Chemistry and Biochemistry, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/28261
► A very interesting class of nanoparticles extensively used for bio-applications is that of hydrogel particles, also called nanogels. There is an increasing interest in the…
(more)
▼ A very interesting class of nanoparticles extensively used for bio-applications is that of hydrogel particles, also called nanogels. There is an increasing interest in the design of hydrogel nanoparticles that have biofunctionality for applications in cell targeting, drug delivery, and biomedicine. The dissertation focuses on developing synthetic strategies for making diverse hydrogel nanoparticles customized to have desirable properties for various bio-applications. We have also investigated the potential of such nanoparticles as coatings for biomedical implants. Chapter 1 gives a brief introduction to hydrogel nanoparticles and the properties that make them attractive for various applications. The details of the syntheses of well defined, stable nanoparticles, commonly used in literature, are described in Chapter 2. Chapter 3 describes our synthesis of hollow sub-50 nm nanogels, which are otherwise difficult to synthesize based on the strategy discussed in Chapter 2. Chapter 4 also demonstrates how simple strategies borrowed from organic chemistry help in producing nanogels with multiple functionalities that are otherwise difficult to obtain, which also is an important advance over the synthetic methods discussed in Chapter 2. Chapter 5 describes how a general strategy based on photoaffinity labeling can yield materials with many applications ranging from optical materials, drug delivery, to biosensing. The latter part of the dissertation describes applications of various nanogels in biology especially as coatings that can control inflammation caused by biomaterials. Chapter 6 describes a method to functionalize flexible biomaterials with the nanogels, thus enabling in vivo investigations of the nanogels as potential coatings for controlling inflammation. Chapter 7 describes the biological studies performed (in collaboration with Garcia Group in the School of Mechanical Engineering at
Georgia Tech) on various nanogels, aimed towards obtaining the most functional and efficient materials for implant applications. Chapter 8 describes application of hollow nanogels for covalently immobilizing biomolecules. This chapter also demonstrates how simple non-functional materials can be made unique and functional by means of traditional organic reactions. Finally, in order to broaden the applications of nanogel based materials.
Advisors/Committee Members: Prof. L. Andrew Lyon (Committee Chair), Prof. Laren Tolbert (Committee Member), Prof. Marcus Weck (Committee Member), Prof. Niren Murthy (Committee Member), Prof. Seth Marder (Committee Member).
Subjects/Keywords: Nanogels; Microgels; Synthesis; Bioconjugation; Nanostructured materials; Biomedical materials; Colloids
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APA (6th Edition):
Singh, N. (2008). Synthetic routes to new core/shell nanogels:design and application in biomaterials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/28261
Chicago Manual of Style (16th Edition):
Singh, Neetu. “Synthetic routes to new core/shell nanogels:design and application in biomaterials.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/28261.
MLA Handbook (7th Edition):
Singh, Neetu. “Synthetic routes to new core/shell nanogels:design and application in biomaterials.” 2008. Web. 15 Jan 2021.
Vancouver:
Singh N. Synthetic routes to new core/shell nanogels:design and application in biomaterials. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/28261.
Council of Science Editors:
Singh N. Synthetic routes to new core/shell nanogels:design and application in biomaterials. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/28261
Georgia Tech
17.
South, Antoinette Bonhivert.
Assembly and dynamic behavior of microgel thin films and their application to biointerfacees.
Degree: PhD, Chemistry and Biochemistry, 2010, Georgia Tech
URL: http://hdl.handle.net/1853/34686
► Hydrogels, which are polymeric cross-linked networks that swell in aqueous environments, are versatile materials that can contain a variety of chemical functionalities, mechanical properties, and…
(more)
▼ Hydrogels, which are polymeric cross-linked networks that swell in aqueous environments, are versatile materials that can contain a variety of chemical functionalities, mechanical properties, and topographical features. Microgels are the stable colloidal form of hydrogel materials that range in size from approximately 100 nm to a few microns in diameter. While they also can exhibit similar properties to those of macrogels, microgels can be used as building blocks in a bottom-up approach to assemble films of higher complexity. In this dissertation, work is focused on understanding the assembly and behavior of microgel thin films as non-fouling surfaces, centrifugally deposited materials, self-healing coatings, and degradable constructs. Non-fouling films were assembled using PEG cross-linked microgels to reduce non-specific protein adsorption and mitigate cellular adhesion. These constructs were assembled in a polyelectrolyte multi-layered fashion, of alternating anionic microgels and cationic linear polymer, to effectively block the substrate from the biological environment and consequently exhibited control over cellular adhesion with the surface. The utility and application of these non-fouling microgel coatings on functional implants was also explored. Centrifugal deposition was used to rapidly generate non-fouling microgel multi-layered interfaces on planar surfaces, and upon closer inspection of the microgel monolayers, it was found that the centrifugally deposited films contained closer-packed microgel assemblies with microgels of smaller footprint size, compared to microgels that are passively adsorbed to the surface. Microgels that are centrifugally deposited may adopt a higher energy chain conformation than passively adsorbed microgels, and this higher energy chain conformation may translate into the multi-layered materials. Nonetheless, the centrifugally deposited non-fouling microgel multi-layered films were found to effectively block macrophage adhesion. Films were also assembled in a polyelectrolyte fashion on soft substrates, and were observed to become significantly damaged under mechanical manipulation (poking, bending, or stretching), but then self-heal upon addition of water. By altering the building blocks of the polyelectrolyte multi-layered films, such as the molecular weight of the polycation between microgel layers or by using anionic rigid spheres as the particle in the assembly, changes in the observed film damage suggest that particle-linear polymer interpenetration and polyvalency likely play an important role in the strength and integrity of the microgel thin films. Fluorescently-labeled microgels were also used to interrogate how the films reorganize in the lateral direction, and these early studies suggest that the microgel multi-layered films reorganize when damaged and also possibly when they are undamaged and simply incubated in an aqueous environment. Additional studies were also conducted on microgels synthesized with a hydrolyzable cross-linker, and by supporting…
Advisors/Committee Members: L. Andrew Lyon (Committee Chair), Andrés García (Committee Member), Jiri Janata (Committee Member), Laren Tolbert (Committee Member), Niren Murthy (Committee Member).
Subjects/Keywords: Biomaterials; Film assembly; Colloids; Thin films; Biomedical materials; Colloids in medicine; Centrifugation
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APA (6th Edition):
South, A. B. (2010). Assembly and dynamic behavior of microgel thin films and their application to biointerfacees. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/34686
Chicago Manual of Style (16th Edition):
South, Antoinette Bonhivert. “Assembly and dynamic behavior of microgel thin films and their application to biointerfacees.” 2010. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/34686.
MLA Handbook (7th Edition):
South, Antoinette Bonhivert. “Assembly and dynamic behavior of microgel thin films and their application to biointerfacees.” 2010. Web. 15 Jan 2021.
Vancouver:
South AB. Assembly and dynamic behavior of microgel thin films and their application to biointerfacees. [Internet] [Doctoral dissertation]. Georgia Tech; 2010. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/34686.
Council of Science Editors:
South AB. Assembly and dynamic behavior of microgel thin films and their application to biointerfacees. [Doctoral Dissertation]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/34686
Georgia Tech
18.
Pathak, Shantanu Chaturvedi.
Characterization of plasma-polymerized polyethylene glycol-like films.
Degree: PhD, Chemical Engineering, 2008, Georgia Tech
URL: http://hdl.handle.net/1853/31789
► A parallel-plate capacitively-coupled plasma deposition system was designed and built for the growth of polyethylene glycol-like films. Deposition rate, bonding structure and dissolution and swelling…
(more)
▼ A parallel-plate capacitively-coupled plasma deposition system was designed and built for the growth of polyethylene glycol-like films. Deposition rate, bonding structure and dissolution and swelling behavior was characterized as a function of input RF power, reactor pressure and substrate temperature to provide information on the relationship between input plasma parameters and film properties. For the conditions studied in this thesis, deposition rates increased at increasing input powers and operating pressures and decreasing substrate temperatures. The PEG-like coatings resembled higher molecular weight solution-polymerized PEG films with a higher crosslinked structure. Manipulation of plasma deposition conditions allowed control of film crosslink density and resulted in tunable dissolution and swelling properties of the PEG-like polymer. At higher applied powers, lower operating pressures, and higher substrate temperatures, films had a higher crosslink density, thus leading to slower dissolution rates and smaller extents of swelling. Void space openings of swelled-state, PEG-like films were determined using electrophoretic drift and diffusion-controlled transport of fluorophore-tagged PAMAM dendrimers into the bulk of the coating. PAMAM dendrimers were used because of their well-defined sizes and negatively-charged succinamic acid surface groups as a means to probe pore sizes of the plasma films. It was estimated that the upper bound of pore size diameters in the plasma polymer was approximately equal to ~5.5-6.0 nm. Positron annihilation lifetime spectroscopy was used to determine average pore sizes and was estimated to equal ~0.60-0.65 nm.
Advisors/Committee Members: Dr. Dennis W. Hess (Committee Chair), Dr. Clifford L. Henderson (Committee Member), Dr. J. Carson Meredith (Committee Member), Dr. L. Andrew Lyon (Committee Member), Dr. Mark R. Prausnitz (Committee Member).
Subjects/Keywords: Barrier film; Plasma polymerization; Stent; Biomedical materials Research; Medical instruments and apparatus; Thin films
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APA (6th Edition):
Pathak, S. C. (2008). Characterization of plasma-polymerized polyethylene glycol-like films. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/31789
Chicago Manual of Style (16th Edition):
Pathak, Shantanu Chaturvedi. “Characterization of plasma-polymerized polyethylene glycol-like films.” 2008. Doctoral Dissertation, Georgia Tech. Accessed January 15, 2021.
http://hdl.handle.net/1853/31789.
MLA Handbook (7th Edition):
Pathak, Shantanu Chaturvedi. “Characterization of plasma-polymerized polyethylene glycol-like films.” 2008. Web. 15 Jan 2021.
Vancouver:
Pathak SC. Characterization of plasma-polymerized polyethylene glycol-like films. [Internet] [Doctoral dissertation]. Georgia Tech; 2008. [cited 2021 Jan 15].
Available from: http://hdl.handle.net/1853/31789.
Council of Science Editors:
Pathak SC. Characterization of plasma-polymerized polyethylene glycol-like films. [Doctoral Dissertation]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/31789
. 
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