Synthesis Of Novel Zwitterionic Polymers
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Synthesis Of Novel Zwitterionic Polymers
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Author : Matthew Skinner
language : en
Publisher:
Release Date : 2018
Synthesis Of Novel Zwitterionic Polymers written by Matthew Skinner and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
This dissertation describes the synthesis, characterization, and investigation of novel zwitterionic polymers containing phosphorylcholine (PC), sulfobetaine (SB), and functional choline phosphate (CP) zwitterions for use as surfactants, self-assembled nanomaterials, and therapeutics. Facile, reproducible, and modular chemistries were utilized for incorporating zwitterions into a range of polymer backbones, and strategies were developed for overcoming difficult challenges encountered in zwitterionic polymer synthesis, especially related to the varying solubility of zwitterions, hydrophobic polymers, and functional comonomers. Synthetic strategies utilized in this work give access to well-defined materials with narrow molecular weight distributions, tunable compositions and architectures, and versatile chemical functionality. Chapter 2 describes the synthesis of water-soluble PC- and SB-functionalized siloxane polymers. PC- and SB-siloxane homopolymers and block copolymers were synthesized using thiol-ene 'click' chemistry, and their assembly in water and at oil-water interfaces was investigated. Chapter 3 describes the preparation of zwitterionic block copolymer analogues of commercial Pluronic® surfactants. PC-containing triblock copolymers were prepared with tunable zwitterion content (5-47 mole percent) and relatively narrow molecular weight distributions. These block copolymer amphiphiles readily formed nanoparticles in water and served as novel surfactants. Through the copolymerization of PC- and CP-methacrylate monomers, functional mimics of conventional Pluronic structures became amenable to crosslinking and the successful synthesis of nanomaterials and robust gels. Chapter 4 presents the in vivo evaluation of poly(2-methacryloyloxyethyl phosphorylcholine)-doxorubicin (polyMPC-Dox) prodrugs for treating human ovarian tumors (SKOV-3). In human ovarian tumor-bearing mice, polyMPC-Dox prodrugs with an approximate Dox loading of 19 weight percent accumulated in tumor tissue at twice the level of free Dox, and animals treated with polyMPC-Dox exhibited enhanced survival and retarded tumor growth compared to conventional Dox treatment. Finally, Chapter 5 augments the polyMPC prodrug concept with the development of polymer-temozolomide (TMZ) conjugates intended for glioblastoma treatment. PolyMPC-TMZ prodrugs were prepared by the controlled free radical copolymerization of MPC and novel TMZ-methacrylate monomers, affording copolymers with random and block architectures. Polymer conjugation significantly improved the solution stability of TMZ, and the antitumor activity of polyMPC-TMZ prodrugs was demonstrated in TMZ-sensitive (U87MG) and TMZ-resistant (T98G) glioblastoma cell lines. The impact of drug loading, polymer architecture, and adjuvant co-delivery on the cytotoxicity of polyMPC-TMZ conjugates was investigated.
Synthesis Of Novel Polymeric Nanoparticles For Hydrophobic And Hydrophilic Drug Delivery
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Author : Marta Sartor
language : en
Publisher:
Release Date : 2010
Synthesis Of Novel Polymeric Nanoparticles For Hydrophobic And Hydrophilic Drug Delivery written by Marta Sartor and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
Modern medicine has achieved extraordinary results with the use of nanotechnologies. The combination of the two disciplines created the modern field of nanomedicine, in which drug delivery is one of the most prominent branches. Several aspects are involved in drug delivery; this work will focus on the drug delivery vehicle. In particular three aspects will be investigated: building material, internal structure and material compatibility. In a first project DNA was proposed as an innovative building material. DNA nanoparticles were made from self-folding of long concatameric repeats of a single strand sequence. Nanoparticles with different sequences created a library that was bio- panned against dendritic cells (DC). Particles from the enriched library were sequenced and individually tested for affinity towards DC. The use of DNA as building material offers several advantages. For instance DNA binding drugs (such as Doxorubicin) can be easily incorporated, and immunostimulatory sequences (such as GpC) and any other encoding sequence can be integrated within the concatamers. In addition, any other molecule or small particle of interest can be conjugated to a short complementary sequence and hybridized on the outer layer of the DNA nanoparticle. DNA nanoparticles' payloads are limited to hydrophilic drugs. In addition to an hydrophobic payload, some therapies require a high loading and steady release. To achieve such results a gradient structure was created within the core of a polymeric nanoparticle. Physical and chemical gradient were considered. A chemical gradient was created by combining a low molecular weigh polycaprolactone (PCL) to a higher molecular weigh poly(lactic-co-glycolic acid) (PLGA). PCL and PLGA have different degradation rate and hydrophobicity. The particles created by combining the two polymers showed properties (such as loading) dependent on the two polymers' proportion into the composition. The chemical gradient nanoparticles are characterized by high loading and steady release of hydrophobic drugs. A new technique was examined to encapsulate hydrophilic oligonucleotides into hydrophobic nanoparticles. PMAL-C8, a zwitterionic polymer, interacts with oligonucleotides of different length and improves their loading into the hydrophobic core. The nanoparticles created were successfully used in transfection experiments, showing the bioavailability of the loaded oligonucleotides.
Synthesis And Characterization Of Amphiphilic Zwitterionic Polymers And The Study Of Solution Behavior Upon Addition Of Surfactant
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Author : Kathryn Johnson
language : en
Publisher:
Release Date : 1999
Synthesis And Characterization Of Amphiphilic Zwitterionic Polymers And The Study Of Solution Behavior Upon Addition Of Surfactant written by Kathryn Johnson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with Solution (Chemistry) categories.
Polyampholytes
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Author : Sarkyt E. Kudaibergenov
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Polyampholytes written by Sarkyt E. Kudaibergenov and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Science categories.
In order to adapt the properties of living materials to their biological functions, nature has developed unique polyelectrolytes with outstanding physical, chemical and mechanical behavior. Namely polyampholytes can be suitable substances to model protein folding phenomenon and enzymatic activity most of biological macromolecules due to the presence of acidic and basic groups. The ability of linear and crosslinked amphoteric macromolecules to adopt globular, coil, helix and stretched conformations and to demonstrate coil-globule, helix-coil phase transitions, and sol-gel, collapsed expanded volume changes in relation to internal (nature and distribution of acid and base substituents, copolymer composition, hydrophobicity etc. ) and external (pH, temperature, ionic strength of the solution, thermodynamic quality of solvents etc. ) factors is very important and constantly attracts the attention of theorists and experimentalists because the hierarchy of amphoteric macromolecules can repeat, more or less, the structural organization of proteins. That is why polyampholytes fall within eyeshot of several disciplines, at least polymer chemistry and physics, molecular biology, colloid chemistry, coordination chemistry and catalysis. The main purpose of this monograph is to bridge the gap between synthetic and natural polymers and to show a closer relationship between two fascinating worlds. The first chapter of the book acquaints the readers with synthetic strategy of "annealed", "quenched" and "zwitterionic" polyampholytes. Radical copolymerization, chemical modification and radiation-chemical polymerization methods are thoroughly considered. Kinetics and mechanism of formation of random, alternating, graft, di-block or tri-block sequences is discussed. The second chapter deals with behavior of polyampholytes in solutions.
Zwitterionic Polymerization For The Synthesis Of High Molecular Weight Cyclic Polymers
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Author : Hayley A. Brown
language : en
Publisher:
Release Date : 2013
Zwitterionic Polymerization For The Synthesis Of High Molecular Weight Cyclic Polymers written by Hayley A. Brown and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Topological isomerism in macromolecules represents a fascinating field of study. Linear polymers form the basis of much of the current scientific understanding of bulk polymer behavior due to their simple structure and synthetic accessibility. In contrast, cyclic polymers remain poorly understood due to the difficulty in generating sufficient quantities of pure samples; in particular, high molecular weight samples where phenomena related to entanglement could be observed have eluded polymer chemists until recently. Among the several strategies employed for the synthesis of high molecular weight cyclic polymers, recent reports have highlighted the utility of zwitterionic ring-opening polymerization (ZROP). Efforts to understand the N-heterocyclic carbene (NHC) mediated ring-opening of strained lactones have led to the development of several mechanistic models. Kinetic studies on the NHC-mediated polymerization of [epsilon]-caprolactone (CL) and [delta]-valerolactone (VL) were conducted to account for the notably high molecular weight cyclic polyerms generated. While the two monomer systems are closely related and polymerize with the same NHC initiators, a difference in the dependence of the reaction rate on monomer is observed. A general mechanism is proposed for the polymerization of VL. Exploiting the utility of ZROP to generate high molecular weight poly([epsilon]-caprolactone) allowed for a comparative study on the bulk crystallization of cyclic PCL and linear PCL across a range of molecular weights. WAXS and SAXS studies show that linear and cyclic PCL exhibit the same global and local crystalline structure but that cyclic PCL crystallizes more rapidly than linear PCL. Isothermal DSC crystallization kinetic studies support this observation and indicate that the difference in crystallization rate increases with increasing molecular weight. Approximating the equilibrium melting temperature of these samples using the Hoffmann-Weeks method indicates that there is no significant difference in Tm0 between cyclic and linear PCL. In an attempt to broaden the scope of initiators for the ZROP of strained lactones, the use of amidines for the polymerization of lactide was explored. 1,8-Diazabicyclo[5.4.0] undec-7-ene (DBU) and 1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) were shown to mediate the ZROP of lactide to give predominantly cyclic poly(lactide) (PLA). A notable solvent effect with no polymerization occurring in neat tetrahydrofuran (THF), fast polymerization with formation of significant amounts of linear PLA in dichloromethane (DCM), and moderate rate of polymerization with minimal formation of linear PLA in THF:DCM blends. DFT computations suggest that the formation of a neutral tricyclic species, a zwitterionic species, and a ketene-aminal are energetically feasible. This ketene-aminal is thought to be the source of the linear PLA observed. Our efforts to develop a more hydrolytically stable family of cyclic polymers led to the investigation of the ZROP of strained cyclic carbosiloxanes. NHC-mediated polymerization of 2,2,5,5-tetramethyl-2,5-disila-1-oxacyclopentane occurs rapidly to give polymers with molecular weights exceeding 106 g/mol. While these polymerizations are difficult to control, the cyclic topology of the resulting polymers could be confirmed by comparative dilute solution viscosity studies and MALDI-TOF MS. As a complimentary strategy to the use of neutral nucleophiles to initiate anionic-like zwitterionic polymerization, neutral Lewis acids were tested for the electrophilic zwitterionic ring opening polymerization (EZROP) of strained heterocycles. Polymerization of 2-ethyl-2-oxaline proceeds slowly at elevated temperature with boron-based Lewis acids to give HF-capped linear chains, determined by MALDI-TOF MS. In contrast, the polymerization of 3,3-dimethyloxetane proceeds very rapidly at room temperature with B(C6F5)3 to give a mixture of polymer products likely resulting from methyl scrambling between chains.
Interfacial Synthesis Polymer Applications And Technology
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Author : Frank Millich
language : en
Publisher:
Release Date : 1977
Interfacial Synthesis Polymer Applications And Technology written by Frank Millich and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1977 with Science categories.
Synthesis And Characterisation Of Novel Ionic Block Copolymers
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Author : Andrew Brian Lowe
language : en
Publisher:
Release Date : 1997
Synthesis And Characterisation Of Novel Ionic Block Copolymers written by Andrew Brian Lowe and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with categories.
Synthesis And Polymerization Of Amino Acid Based Zwitterionic Surfactants
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Author : Li Hui Ong
language : en
Publisher:
Release Date : 1998
Synthesis And Polymerization Of Amino Acid Based Zwitterionic Surfactants written by Li Hui Ong and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Polymerization categories.
New Zwitterionic Polymers For Antifouling Applications
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Author : Alejandro Martínez Guajardo
language : en
Publisher:
Release Date : 2024*
New Zwitterionic Polymers For Antifouling Applications written by Alejandro Martínez Guajardo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024* with categories.
The remarkable antifouling properties of zwitterionic polymers in controlled environments are often counteracted by their delicate mechanical stability. In order to improve the mechanical stabilities of zwitterionic hydrogels, the effect of increased crosslinker densities was thus explored. In a first approach, terpolymers of zwitterionic monomer 3-[N -2(methacryloyloxy)ethyl-N,N-dimethyl]ammonio propane-1-sulfonate (SPE), hydrophobic monomer butyl methacrylate (BMA), and photo-crosslinker 2-(4-benzoylphenoxy)ethyl methacrylate (BPEMA) were synthesized. Thin hydrogel coatings of the copolymers were then produced and photo-crosslinked. Studies of the swollen hydrogel films showed that not only the mechanical stability but also, unexpectedly, the antifouling properties were improved by the presence of hydrophobic BMA units in the terpolymers. Based on the positive results shown by the amphiphilic terpolymers and in order to further test the impact that hydrophobicity has on both the antifouling properties of zwitterionic hydrogels and on their mechanical stability, a new amphiphilic zwitterionic methacrylic monomer, 3-((2-(methacryloyloxy)hexyl)dimethylammonio)propane-1-sulfonate (M1), was synthesized in good yields in a multistep synthesis. [...].
Synthesis Of Novel Cyclic Monomers For Hydrogel Polymers
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Author : Christopher Brian St. Pourcain
language : en
Publisher:
Release Date : 1992
Synthesis Of Novel Cyclic Monomers For Hydrogel Polymers written by Christopher Brian St. Pourcain and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with categories.