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Embargado hasta 09/04/2023 Polymersomes and related self-assembled nanostructures displaying Aggregation-Induced Emission (AIE) are highly relevant for plenty of applications in imaging, biology and functional devices. Experimentally simple, scalable and universal strategies for on-demand self-assembly of polymers rendering well-defined nanostructures are highly desirable. A purposefully designed combination of amphiphilic block copolymers including tunable lengths of hydrophilic polyethylene glycol (PEGm) and hydrophobic AIE polymer poly(tetraphenylethylene-trimethylenecarbonate) (P(TPE-TMC)n) has been studied at the air/liquid interface. The unique 2D assembly properties have been analyzed by thermodynamic measurements, UV-vis reflection spectroscopy and photoluminescence in combination with molecular dynamics simulations. The (PEG)m-b-P(TPE-TMC)n monolayers formed tunable 2D nanostructures self-assembled on demand by adjusting the available surface area. Tuning of the PEG length allows to modification of the area per polymer molecule at the air/liquid interface. Molecular detail on the arrangement of the polymer molecules and relevant molecular interactions has been convincingly described. AIE fluorescence at the air/liquid interface has been successfully achieved by the (PEG)m-b-P(TPE-TMC)n nanostructures. An experimentally simple 2D to 3D transition allowed to obtain 3D polymersomes in solution. This work suggests that engineered amphiphilic polymers for AIE may be suitable for selective 2D and 3D self-assembly for imaging and technological applications.

Linear-dendritic block copolymer (LDBCs) are highly attractive candidates for smart drug delivery vehicles. Herein, we report an amphiphilic poly[(ethylene glycol) methyl ether methacrylate] (POEGMA) linear-peptide dendritic prodrug of doxorubicin (DOX) prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. A hydrophobic dye-based photosensitizer chlorin e6 (Ce6) was employed for encapsulation in the prodrug nanoparticles (NPs) to obtain a LDBCs-based drug delivery system (LD-DOX/Ce6) which offered a combination cancer therapy. Due to the presence of Gly-Phe-Leu-Gly peptides and hydrazone bonds in the prodrug structure, LD-DOX/Ce6 were degraded into small fragments, thus specifically triggering the intracellular release of DOX and Ce6 in the tumor microenvironment. Bioinformatics analysis suggested that LD-DOX/Ce6 with laser irradiation treatment significantly induced apoptosis, DNA damage and cell cycle arrest. The combination treatment could not only suppress tumor growth, but also significantly reduced tumor metastasis compared with treatments with DOX or Ce6 through regulating EMT pathway, TGFβ pathway, angiogenesis and the hypoxia pathway. LD-DOX/Ce6 displayed a synergistic chemo-photodynamic anti-tumor efficacy, resulting in a high inhibition in tumor growth and metastasis, while maintaining an excellent biosafety. Therefore, this study has demonstrated potential of the biodegradable and tumor microenvironment-responsive LDBCs as an intelligent multifunctional drug delivery vehicle for high-efficiency cancer combination therapy. This article is protected by copyright. All rights reserved.

Wide usage of clay-based materials in industry requires investigations concerning efficient modification techniques to control their mechanical behavior in aqueous media. The challenging problem in this field involves minimization of the modifying agent content to provide marked changes in the operating characteristics of the material. In this work, the physicochemical, mechanical and structural aspects of the interaction of capillary water-saturated kaolinite with polyelectrolytes were studied. Modification of kaolinite with a negligible amount (0.1 wt.%) of hydrophilic and amphiphilic polyelectrolytes provides the control for rheological parameters of kaolinite suspensions such as storage and loss modulus in the range of three orders of magnitude. The results obtained reveal the wide possibilities for the production of a spectrum of clay materials using minor amounts of polymer modifying agents.

Amphiphilic block polyelectrolytes are known for their remarkable thickening properties in water solution, originating from their ability to self-assemble into large micellar aggregates. This makes them promising flooding agent for chemical enhanced oil recovery (cEOR). However, to the best of our knowledge, they have not yet been directly investigated for this purpose. In this work, a survey of relevant properties for EOR (rheology, filterability and emulsification), and laboratory scale oil recovery experiments, were performed on water solutions of polystyrene-block-poly(methacrylic acid) amphiphilic block polyelectrolytes, and compared with a commercial partially hydrolyzed polyacrylamide (HPAM), to evaluate the real potential in EOR applications for the first time. It was found that the recovery of amphiphilic block copolymers in low salinity brine (0.2% concentration of NaCl) is remarkably higher than that of HPAM at comparable weight concentration and shear viscosity, despite a much lower molecular weight. Effect of salinity and emulsification properties of the studied polymers have also been preliminarily investigated. Our results suggest that the recovery mechanism of these polymers differs from the traditional mechanism of polymer flooding, possibly due to emulsification of the oil. In conclusion, the studied amphiphilic block polyelectrolytes show promise as chemical agents in low salinity polymer flooding.

Kriyojeller, kriyopolimerizasyon (kriyotropik jelleşme) şartlarında sentezlenen hidrojel sınıfına ait polimerik jel matrislerdir. Kriyojeller, genellikle birbiriyle bağlı süpermakrogözenekli süngerimsi esnek bir yapıya, yüksek gözenek yoğunluğuna sahip, sentezlenirken çözücü ve gözenek yapıcı olarak toksik madde gerektirmemeleri ve mekanik olarak dayanıklı olmaları sayesinde biyomedikal amaçlı birçok alanda uygulamaya sahiptirler. Amfifilik blok kopolimerlerin devamlı artan bir şekilde uygulamaları nedeniyle bu tür polimerleri üretmek; fizikokimyasal özelliklerini araştırmak ve geliştirmek gerekmektedir. Amfifilik kopolimerler hidrofobik ve hidrofilik polimerlerden ibaret hem polar hem non-polar fazlara ilgi duyan kopolimerlerdir. Birbiriyle uyuşmayan bloklardan oluşan bu kopolimerlerin amfifilik tabiatı onlara seçimli çözücülerde çok farklı özellikler kazandırır. Kütle yapısı içinde olduğu gibi aynı zamanda yüzeyde de mikrofaz ayrımına sebep olurlar. Seçimli ortam varlığında, çözücü içinde veya yüzeylerde, kendi içlerinde düzenlenmeleri, bir bloka göre çözücü ortamında diğer blok çökeceğinden dolayı kolloidal dağılım halini alır ve böylece miseller şeklinde yığılımlara, mikroemülsiyonlara ve absorblanmış polimer tabakalarının oluşmasına sebep olurlar. Bu tez kapsamında, amfifilik türden yeni nesil polimerik sistemler amfifilik kriyojellerin sentezlenmesi ve karakterizasyonu amaçlanmıştır. Oldukça hidrofilik yapıda olduğu bilinen kriyojeller, hidroksillenmiş polimerik yağ asitleri ile aynı polimer matrisinde buluşarak, hidrofilik ve hidrofobik yapıyı bir arada bulunduran yeni nesil amfifilik kriyojel sentezlenmesi amaçlanmaktadır. Yapısal olarak literatürde pek rastlanmayan yeni amfifilik kriyojel sentezi için ana monomer HEMA (2-hidroksi etil metakrilat) monomeri tercih edilmiştir. HEMA monomeri, suda çözünebilir, biyouyumludur, kimyasal ve hidrolitik olarak kararlı yapıdadır. HEMA monomerinin yanında komonomer olarak önce oto-oksidasyon, sonrasında ise hidroksilasyon reaksiyonuna tabi tutularak modifiye edilmiş soya yağından üretilen polimerik linoleik yağ asidi kullanılmıştır. Sentezlenecek poly(HEMA-LinaOH) kriyojellerinin içeriğindeki hidroksillenmiş yağ asidi oranının değişimine karşılık kriyojelin morfolojik ve ısısal analiz değişimleri incelenmiştir. Sentezlenen kriyojellerin şişme özellikleri su ve farklı çözücülerdeki sıvı tutma kapasitesine göre incelenmiştir. Kriyojellerin yapısal karakterizasyonları için FTIR-ATR, yüzey ve morfolojik analizleri için SEM, elementel analiz EDAX, ısısal analileri için DSC, TGA yöntemleri kullanılarak yapılmıştır. Anahtar Kelimeler: Amfifilik polimerler, Kriyojel, HEMA (2-hidroksi etil metakrilat), LinaOH, Linoleik asit Cryogels are polymeric gel matrices belonging to the class of hydrogels synthesized under cryopolymerization conditions. Cryogels are generally used in many fields for biomedical purposes thanks to their interconnected supermacroporous spongy flexible structure, high pore density, not requiring toxic substances as a solvent and pore maker when synthesized, and being mechanically durable. Due to the ever-increasing application of amphiphilic block copolymers, it is possible to produce such polymers; It is necessary to investigate and improve its physicochemical properties. Amphiphilic copolymers are copolymers of interest in both polar and non-polar phases consisting of hydrophobic and hydrophilic polymers. The amphiphilic nature of these copolymers, which consist of incompatible blocks, gives them very different properties in selective solvents. They cause microphase separation on the surface as well as in the mass structure. In the presence of selective media, in the solvent or on the surfaces, their arrangement within themselves takes the form of colloidal dispersion due to the fact that the other block will collapse in the solvent medium relative to one block, and thus cause agglomerations in the form of micelles, microemulsions and the formation of absorbed polymer layers.Within the scope of this thesis, the synthesis and characterization of amphiphilic type new generation polymeric systems amphiphilic cryogels are aimed. It is aimed to synthesize a new generation amphiphilic cryogel that contains hydrophilic and hydrophobic structure by meeting the hydroxylated fatty acids in the same polymer mix and polymerizing together, which are known to be highly hydrophilic. The main monomer HEMA (2-hydroxy ethyl methacrylate) was preferred for the synthesis of new amphiphilic cryogel which is structurally not encountered in the literature. HEMA monomer is water soluble, biocompatible, chemically and hydrolytically stable. In addition to HEMA monomer, linoleic fatty acid produced from modified soybean oil by first auto-oxidation and then hydroxylation reaction was used as comonomer. The morphological and thermal analysis changes of the cryogel against the change in the hydroxylated fatty acid ratio in the content of the poly (HEMA-LinaOH) cryogels to be synthesized were examined. The swelling properties of the synthesized cryogels were investigated according to their liquid holding capacity in water and different solvents. FTIR-ATR for structural characterization of cryogels, SEM for surface and morphological analysis, EDAX for elemental analysis, DSC for thermal analysis, TGA methods were used. Keywords: Amphiphilic polymers, Cryogel, HEMA (2-hydroxy ethyl methacrylate), LinaOH, Linoleic acid

Hybrid microparticles based on an iron core and an amphiphilic polymeric shell have been prepared to respond simultaneously to magnetic and ultrasonic fields and variation in the surrounding pH to trigger and modulate the delivery of doxorubicin. The microparticles have been developed in four steps: (i) synthesis of the iron core, (ii) surface modification of the core, (iii) conjugation with the amphiphilic poly(lactic acid)-grafted chitosan, and (iv) doxorubicin loading. The particles demonstrate spherical shape, a size in the range of 1&ndash, 3 &micro, m and surface charge that is tuneable by changing the pH of the environment. The microparticles demonstrate good stability in simulated physiological solutions and are able to hold up to 400 &micro, g of doxorubicin per mg of dried particles. The response to ultrasound and the changes in the shell structure during exposure to different pH levels allows the control of the burst intensity and release rate of the payload. Additionally, the magnetic response of the iron core is preserved despite the polymer coat. In vitro cytotoxicity tests performed on fibroblast NIH/3T3 demonstrate a reduction in the cell viability after administration of doxorubicin-loaded microparticles compared to the administration of free doxorubicin. The application of ultrasound causes a burst in the release of the doxorubicin from the carrier, causing a decrease in cell viability. The microparticles demonstrate in vitro cytocompatibility and hemocompatibility at concentrations of up to 50 and 60 &micro, g/mL, respectively.

© 2020 by the authors., A series of well-defined antimicrobial polymers composed of comonomers bearing thiazole ring (2-(((2-(4-methylthiazol-5-yl)ethoxy)carbonyl)oxy)ethyl methacrylate monomer (MTZ)) and non-hemotoxic poly(ethylene glycol) side chains (poly(ethylene glycol) methyl ether methacrylate (PEGMA)) were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. By post-polymerization functionalization strategy, polymers were quaternized with either butyl or octyl iodides to result in cationic amphiphilic copolymers incorporating thiazolium groups, thus with variable hydrophobic/hydrophilic balance associated to the length of the alkylating agent. Likewise, the molar percentage of PEGMA was modulated in the copolymers, also affecting the amphiphilicity. The antimicrobial activities of these cationic polymers were determined against Gram-positive and Gram-negative bacteria and fungi. Minimum inhibitory concentration (MIC) was found to be dependent on both length of the alkyl hydrophobic chain and the content of PEGMA in the copolymers. More hydrophobic octylated copolymers were found to be more effective against all tested microorganisms. The incorporation of non-ionic hydrophilic units, PEGMA, reduces the hydrophobicity of the system and the activity is markedly reduced. This effect is dramatic in the case of butylated copolymers, in which the hydrophobic/hydrophilic balance is highly affected. The hemolytic properties of polymers analyzed against human red blood cells were greatly affected by the hydrophobic/hydrophilic balance of the copolymers and the content of PEGMA, which drastically reduces the hemotoxicity. The copolymers containing longer hydrophobic chain, octyl, are much more hemotoxic than their corresponding butylated copolymers., This research was funded by MINECO, Project MAT2016-78437-R, the Agencia Estatal de Investigación (AEI, Spain), and Fondo Europeo de Desarrollo Regional (FEDER, EU).

In order to reduce the viscosity of heavy oil, the performance of emulsifying viscosity reducers is limited. In this study, a new kind of amphiphilic low molecular weight viscosity reducer was prepared by emulsion copolymerization of acrylamide (AM), acrylic acid (AA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and Butene benzene (PB). The synthesis feasibility and viscosity reduction mechanism of viscosity reducer in heavy oil were explored using Materials Studio software from the perspective of molecular dynamics. The results of the molecular dynamics simulation revealed that the addition of viscosity reducer into heavy oil varied the potential energy, non-potential energy, density and hydrogen bond distribution of heavy oil. Benefiting from its structure, the benzene ring in PB was well embedded in the interlayer structure of asphaltene, contributing to weaken the network structure of the heavy oil. Moreover, the two strong polar groups (COO− and SO3−) of AA and AMPS, which constituted the branched chains of the viscosity reducer’s molecular structure, gradually disassembled the network structure from the ‘inward’ to the ‘outward’ of the heavy oil network structure, thereby driving heavy oil viscosity reduction (as clarified by molecular dynamics). Owing to its temperature resistance, this kind of new amphiphilic low molecular copolymer could be an effective viscosity reducer for heavy oil cold recovery at elevated temperatures.

The request of new materials, matching strict requirements to be applied in precision and patient-specific medicine, is pushing for the synthesis of more and more complex block copolymers. Amphiphilic block copolymers are emerging in the biomedical field due to their great potential in terms of stimuli responsiveness, drug loading capabilities and reversible thermal gelation. Amphiphilicity guarantees self-assembly and thermoreversibility, while grafting polymers offers the possibility of combining blocks with various properties in one single material. These features make amphiphilic block copolymers excellent candidates for fine tuning drug delivery, gene therapy and for designing injectable hydrogels for tissue engineering. This manuscript revises the main techniques developed in the last decade for the synthesis of amphiphilic block copolymers for biomedical application. Strategies for fine tuning the properties of these novel materials during synthesis are discussed. A deep knowledge of the synthesis techniques and their effect on the performance and the biocompatibility of these polymers is the first step to move them from the lab to the bench. Current results predict a bright future for these materials in paving the way towards a smarter, less invasive, while more effective, medicine.

Once removed from their natural environment, membrane proteins depend on membrane‐mimetic systems to retain their native structures and functions. To this end, lipid‐bilayer nanodiscs that are bounded by scaffold proteins or amphiphilic polymers such as styrene/maleic acid (SMA) copolymers have been introduced as alternatives to detergent micelles and liposomes for in vitro membrane‐protein research. Herein, we show that an alternating diisobutylene/maleic acid (DIBMA) copolymer shows equal performance to SMA in solubilizing phospholipids, stabilizes an integral membrane enzyme in functional bilayer nanodiscs, and extracts proteins of various sizes directly from cellular membranes. Unlike aromatic SMA, aliphatic DIBMA has only a mild effect on lipid acyl‐chain order, does not interfere with optical spectroscopy in the far‐UV range, and does not precipitate in the presence of low millimolar concentrations of divalent cations.

WOS: 000373550600023 PubMed ID: 26977718 We report the synthesis of an amphiphilic triblock copolymer composed of a hydrophilic polyethylene glycol) (PEG) block, a central poly(acrylic acid) (PAA) block, and a hydrophobic poly(methyl methacrylate) (PMMA) block using atom transfer radical polymerization technique. We examined the self-assembly of PEG-b-PAA-b-PMMA copolymers in aqueous solutions forming nanosized micelles and their ability to encapsulate hydrophobic guest molecules such as Nile Red (NR) dye and cabazitaxel (CTX, an anticancer drug). We used 2,2 beta'-(propane-2,2-diylbis(oxy))-diethanamine to react with the carboxylic acid groups of the central PAA block forming acid-labile, shell cross-linked micelles (SCLM). We investigated the loading efficiency and release of different guest molecules from non-cross-linked micelles (NSCLM) and shell cross-linked micelles (SCLM) prepared by reacting 50% (SCLM-50) and 100% (SCLM-100) of the carboxylic acid groups in the PAA in physiologic (pH 7.4) and acidic (pH 5.0) buffer solutions as a function of time. We examined the uptake of NR-loaded NSCLM, SCLM-50, and SCLM-100 micelles into PC-3 and C4-2B prostate cancer cells and the effect of different micelle compositions on membrane fluidity of both cell lines. We also investigated the effect of CTX-loaded NSCLM, SCLM-50, and SCLM-100 micelles on the viability of PC-3 and C4-2B cancer cells compared to free CTX as a function of drug concentration. Results show that PEG-b-PAA-b-PMMA polymers form micelles at concentrations >= 11 mu g/mL with an average size of 40-50 nm. CTX was encapsulated in PEG-b-PAA-b-PMMA micelles with 55% loading efficiency in NSCLM. In vitro release studies showed that 30% and 85% of the loaded CTX was released from SCLM-50 micelles in physiologic (pH 7.4) and acidic (pH 5.0) buffer solutions over 30 h, confirming micelles' sensitivity to solution pH. Results show uptake of NSCLM and SCLM into prostate cancer cells delivering their chemotherapeutic cargo, which triggered efficient cancer cell death. PEG-b-PAA-b-PMMA micelles were not hemolytic and did not cause platelet aggregation, which indicate their biocompatibility. National Ministry of Education of the Republic of Turkey [1416]; Ministry of Higher Education of the Arab Republic of Egypt O.A. wishes to recognize the financial support of the National Ministry of Education of the Republic of Turkey (Program #:1416). I.Y. recognizes the financial support of the Ministry of Higher Education of the Arab Republic of Egypt through the Joint Supervision Fellowship Program. I.Y. also recognizes the support of Dr. Ahmed Fadda, Dr. ElSayed Afsah, and Dr. Ibrahim El-Sherbiny for serving as the dissertation committee at Mansoura University, Mansoura, Egypt. The authors thank Dr. Daniel Eitzman and Dr. Jinsang Kim at the University of Michigan for granting access to the Aggro-Link Data Reduction System (Chrono-log Corporation, Havertown, PA) and the QM4 Fluorescence Spectrophotometer (PerkinElmer, Waltham, MA) used to measure platelets aggregation and changes in albumin fluorescence, respectively. The authors also thank Mr. Ahmet Emrehan Emre for his technical assistance with electron microscopy imaging.

An amphiphilic derivative of chitosan containing quaternary ammonium and myristoyl groups, herein named as ammonium myristoyl chitosan (DMCat), was synthesized by reacting glycidyltrimethylammonium chloride (GTMAC) and myristoyl chitosan (DMCh). The success of the modification was confirmed using Fourier-transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (NMR) spectroscopy. The average degrees of alkylation and quaternization ( D Q &macr, ) were determined by using 1H NMR and conductometric titration. The zeta potential of the micelles was higher than 28 mV while its average size and encapsulation efficiency ranged from 280 nm to 375 nm and 68% to 100%, respectively. The in vitro cytotoxicity of the unloaded and curcumin (CUR)-loaded micelles was tested against Caco-2 and HT29-MTX intestinal epithelial cell lines. The results showed no cytotoxic effect from loaded and unloaded micelles as compared to free CUR. In the permeability test, it was observed that both types of micelles, i.e., DMCh and DMCat, improved CUR permeability. Additionally, higher permeability was verified for both systems in Caco-2/HT29-MTX:Raji B because of the mucoadhesive character of chitosan and its ability to open tight junctions. The results indicated that DMCat micelles, due to the physico-chemical, improved characteristics may be a promising carrier to encapsulate CUR aiming cancer therapy.

Thermo-reversible supramolecular networks from polyisoprene-block-polystyrene-block-polyisoprene (ISI) triblock copolymers with short, functionalized polyisoprene (PI) blocks were investigated. Functional groups along the PI blocks were hydroxyl groups, ester groups with a carboxylic end-group (-O-CO-CH2-CH2-COOH), and urethane groups with an amine end-group&mdash, synthesized from various types of diamines&mdash, (-O-CO-NH-R-NH2). Dynamic mechanical analysis (DMA) was performed at temperatures above Tg of polystyrene (PS) to investigate the influence of the different functional groups, the molecular weight, and the composition of the triblock copolymers on the materials&rsquo, properties. Furthermore, comparisons to DMA results of diblock copolymers, modified in the same way, will be presented. Arising reversible and irreversible processes observed during DMA experiments will be compared to results from temperature-dependent Fourier transform infrared (FTIR) spectroscopy. For the elaborated systems, the transition from reversible, hydrogen-bonded to permanently cross-linked networks was observed at around 150 &deg, C.

Aqueous solutions of amphiphilic polymers usually comprise of inter- and intramolecular associations of hydrophobic groups often leading to a formation of a rheologically significant reversible network at low concentrations that can be identified using techniques such as static light scattering and rheometry. However, in most studies published till date comparing water soluble polymers with their respective amphiphilic derivatives, it has been very difficult to distinguish between the effects of molecular mass versus hydrophobic associations on hydrodynamic (intrinsic viscosity [η]) and thermodynamic parameters (second virial coefficient A 2), owing to the differences between their degrees of polymerization. This study focuses on the dilute and semi-dilute solutions of hydroxyethyl cellulose (HEC) and its amphiphilic derivatives (hmHEC) of the same molecular mass, along with other samples having a different molecular mass using capillary viscometry, rheometry and static light scattering. The weight average molecular masses (M W ) and their distributions for the non-associative HEC were determined using size exclusion chromatography. Various empirical approaches developed by past authors to determine [η] from dilute solution viscometry data have been discussed. hmHEC with a sufficiently high degree of hydrophobic modification was found to be forming a rheologically significant network in dilute solutions at very low concentrations as opposed to the hmHEC with a much lower degree of hydrophobic modification which also enveloped the hydrophobic groups inside the supramolecular cluster as shown by their [η] and A 2. The ratio A 2 M W /[η], which takes into account hydrodynamic as well as thermodynamic parameters, was observed to be less for associative polymers compared to that of the non-associative polymers.

Synthetic amphiphilic polymers have been established as potentially efficient agents to combat widespread deadly infections involving antibiotic resistant superbugs. Incorporation of poly(ethylene glycol) (PEG) side chains into amphiphilic copolymers can reduce their hemolytic activity while maintaining high antibacterial activity. Our study found that the incorporation of PEG has substantially different effects on the hemolytic and antibacterial activities of copolymers depending on structural variations in the positions of cationic centers relative to hydrophobic groups. The PEG side chains dramatically reduced the hemolytic activities in copolymers with hydrophobic hexyl and cationic groups on the same repeating unit. However, in case of terpolymers with cationic and lipophilic groups placed on separate repeating units, the presence of PEG has significantly lower effect on hemolytic activities of these copolymers. PEGylated terpolymers displayed substantially lower activity against Staphylococcus aureus (S. aureus) than Escherichia coli (E. coli) suggesting the deterring effect of S. aureus’ peptidoglycan cell wall against the penetration of PEGylated polymers. Time-kill studies confirmed the bactericidal activity of these copolymers and a 5 log reduction in E. coli colony forming units was observed within 2 h of polymer treatment.

Hydrogels with different degrees of hydrophilicity and cross-link densities were synthesized starting from epoxy monomers and aliphatic amines. Their chemical cross-link density was varied by changing the functionality of monomers or the resin/hardener ratio. Physical cross-links were introduced by incorporating in the polymer network hydrophobic segments, which in aqueous media give hydrophobic interaction. It was shown that the swelling degree, thermosensitivity and mechanical properties of these hydrogels can be easily tailored by changing the concentration and relative amount of physical and chemical cross-links.Hydrogels with different degrees of hydrophilicity and cross-link densities were synthesized starting from epoxy monomers and aliphatic amines. Their chemical cross-link density was varied by changing the functionality of monomers or the resin/hardener ratio. Physical cross-links were introduced by incorporating in the polymer network hydrophobic segments, which in aqueous media give hydrophobic interaction. It was shown that the swelling degree, thermosensitivity and mechanical properties of these hydrogels can be easily tailored by changing the concentration and relative amount of physical and chemical cross-links.

Folding an amphiphilic polymer around a transition metal affords homogeneous, water-soluble, and stable catalysts that are active in complex, cellular media. This chapter summarizes the progress made in this area over the last decade and explores how far research at the interface of polymer chemistry, homogeneous transition-metal-based catalysis, and disease biology can provide solutions to the treatment of complex diseases such as cancer. We start with a short overview on how single polymer chains can be constrained in their conformation by intramolecular covalent and noncovalent cross-linking processes. We then continue with discussing the compatibility of these folded/collapsed single polymer chains in and around cells. Because the stability and compatibility for these systems in water and complex media is promising, a number of biomedical applications are highlighted. First, gadolinium- and gallium-based folded polymers are attractive for magnetic resonance imaging and single-photon emission computerized tomography, respectively. In addition, folded polymers successfully serve as carriers for porphyrin-based systems that upon irradiation produce singlet oxygen, which is highly promising for photodynamic therapy. Moreover, folded polymers are also promising candidates for drug-carrier materials. Finally, examples are presented in which folded polymers operate as either carriers of reactive species or carriers of transition-metal-based catalysts to induce synthesis in living cells. The field of folded single-chain polymers is still young, and the examples discussed in this chapter highlight that many exciting challenges in the area of biomedical applications are awaiting. To successfully integrate current and future systems in complex cellular media, a seamless integration of the different disciplines is crucial.

Self-assembly of macromolecules with ligands is an intricate dynamic process that depends on a wide variety of parameters and forms the basis of many essential biological processes. We elucidate the underlying energetic processes of self-assembly in a model system consisting of amphiphilic core-shell polymers interacting with paramagnetic, amphiphilic ligand molecules from temperature-dependent continuous wave electron paramagnetic resonance (CW EPR) spectroscopy subsequent to spectral simulation. The involved processes as observed from the ligands’ point of view are either based on temperature-dependent association constants (KA,j,k) or dynamic rotational regime interconversion (IC) constants (KIC,j,k). The interconversion process describes a transition from Brownian (b1) towards free (b2) diffusion of ligand. Both processes exhibit non-linear van’t Hoff (lnK vs. T−1) plots in the temperature range of liquid water and we retrieve decisive dynamic information of the system from the energetic fingerprints of ligands on the nanoscale, especially from the temperature-dependent interconversion heat capacity (∆C°P,IC).

Made available in DSpace on 2018-12-11T17:33:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-08-02 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) In this study, amphiphilic polymers were investigated as biomaterials that can control dexamethasone (DXM) release. Such materials present interfacial properties in the presence of water and an oily phase that can result in lyotropic liquid crystalline systems (LLCS). In addition, they can form colloidal nanostructures similar to those in living organisms, such as bilayers and hexagonal and cubic phases, which can be exploited to solubilize lipophilic drugs to sustain their release and enhance bioavailability. It was possible to obtain lamellar and hexagonal phases when combining polyoxyethylene (20) cetyl ether (CETETH-20) polymer with oleic acid (OA), N-methylpyrrolidone (P), isopropyl myristate (IM), and water. The phases were characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheological, textural, and bioadhesion analyses followed by an in vitro release assay. All samples showed elastic behavior in the rheology studies and hexagonal samples containing P and IM showed the highest adhesiveness. The drug release profile of all LLCS presented an average lag time of 3 h and was best fitted to the Korsmeyer-Peppas and Weibull models, with controlled release governed by a combination of diffusion and erosion mechanisms. These systems are potential carriers for DXM and can be explored in several routes of administration, providing potential advantages over conventional pharmaceutical forms. School of Pharmaceutical Sciences São Paulo State University (UNESP) School of Pharmaceutical Sciences Federal University of Alfenas UNIFAL-MG Human and Natural Sciences Center Federal University of ABC Instituto Interuniversitario Reconocimiento Molecular y Desarrollo Tecnológico Departamento de Farmacia y Tecnología Farmacéutica y Parasitología Universidad de Valencia School of Pharmaceutical Sciences São Paulo State University (UNESP) CAPES: #1241/2014

In this paper, we studied the aggregation of amphiphilic polymer epoxy-terminated polydimethylsiloxane (PDMS-E) grafted gelatin (PGG) in water induced by methanol, ethanol, 2-propanol, acetone, tetrahydrofuran (THF), and 1,4-dioxane. The aggregation pattern of the polymer was monitored by infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. It was revealed that the aggregate morphology showed clear dependence on the solvent polarity. The PGG aggregates had regular spherical morphology in polar solvents, including water, methanol, ethanol, 2-propanol, and acetone. The coating performance was evaluated by X-ray photoelectron spectroscopy and friction experiment, and PGG and acetone coating exhibited excellent coating performance on the surface of pigskin. Gel was formed in acetone and tetrahydrofuran (THF) with the slow evaporation of solvent, and this property can possibly be applied to industrial sewage treatment. White precipitate and soft film were formed in non-polar 1,4-dioxane.

Fouling Release Coatings are marine antifouling coatings based on silicone elastomers. Contrary to commonly used biocide-based antifouling coatings, they do not release biocides into the marine environment, however, they suffer from poor antifouling efficacy during idle periods. To improve their antifouling performances in static conditions, various amounts of hydrolyzable polymers were incorporated within a silicone matrix. These hydrolyzable polymers were chosen for the well-known hydrolytic degradation mechanism of their main chain, e.g. poly(&epsilon, caprolactone) (PCL), or of their ester pending groups, e.g. poly(bis(trimethylsilyloxy)methylsilyl methacrylate) (PMATM2). The degradation kinetics of such hydrolyzable silicone coatings were assessed by mass loss measurements during immersion in deionized water. Coatings containing PMATM2 exhibited a maximum mass loss after 12 weeks, whereas PCL-based coatings showed no significant mass loss after 24 weeks. Dynamic contact angle measurements revealed the modifications of the coatings surface chemistry with an amphiphilic behavior after water exposure. The attachment of macrofoulers on these coatings were evaluated by field tests in the Mediterranean Sea, demonstrating the short or long-term antifouling effect of these hydrolyzable polymers embedded in the silicone matrix. The settlement of A. amphitrite barnacles on the different coatings indicated inhospitable behaviors towards larval barnacles for coatings with at least 15 wt % of additives.

Novel thermo- and pH-dual responsive amphiphilic copolymers were synthesized based on hyperbranched polyethylenimine (PEI) by grafting L-phenylalanine. The phenylalanine-modified PEI exhibited lower cytotoxicity than commercial PEI. These copolymers showed the phenomena of phase transitions in response to pH and temperature. The dilute copolymer solution at lower pH displayed the higher LCST. Furthermore, LCST increased with the increasing of phenylalanine grafting density. LCST of these copolymers were tunable from 7.2 to 59.6 °C by the degree of amidation and pH of solution. DLS and TEM experiments certified that the copolymer chains aggregated to form small size particles as increasing the temperature above LCST. For these reasons, the obtained smart copolymers were considered to be potential gene/drug carriers in biomedical field.

Nanospheres and nanocapsules of an amphiphilic copolymer having methylated polyethylene glycol and hexadecyl lateral groups were prepared by the solvent displacement method and using confined impinging jet mixers. Degradation, thermal properties and crystalline structure were investigated by 1H NMR, DSC, optical and electron microscopy, and X-ray diffraction techniques. Interestingly, pegylated chains hydrolyzed through ester bond cleavage, whereas the more hydrophobic hexadecyl ester groups were resistant to degradation in aqueous media. The copolymer crystallized from the melt, giving rise to spherulites with a negative birefringence and domains corresponding to crystallization of the different lateral groups. Size distribution and morphology of nanocapsules and nanospheres were mainly evaluated by electron microscopy, direct observation or negative staining of samples. Nanocapsules were characterized by a stable membrane with a thickness close to 5 nm that allowed efficient encapsulation of a triglyceride oil. Triclosan was selected as an example of a hydrophobic drug to be loaded in both nanospheres and nanocapsules. The release behavior of these dosage forms was clearly different. Thus, the Burst effect was practically suppressed when using nanocapsules; in addition, these showed a sustained, controlled release over a greater time period. Antimicrobial activity of triclosan loaded nanospheres and nanocapsules was evaluated using Gram-negative and Gram-positive bacteria. The former were highly sensitive to the released triclosan whereas the latter strongly depended on the number of particles in the culture medium

Atherosclerosis, a leading cause of mortality in developed countries, is characterized by the buildup of oxidized low-density lipoprotein (oxLDL) within the vascular intima, unregulated oxLDL uptake by macrophages, and ensuing formation of arterial plaque. Amphiphilic polymers (AMPs) comprised of a branched hydrophobic domain and a hydrophilic poly(ethylene glycol) (PEG) tail have shown promising anti-atherogenic effects through direct inhibition of oxLDL uptake by macrophages. In this study, five AMPs with controlled variations were evaluated for their micellar and structural stability in the presence of serum and lipase, respectively, to develop underlying structure-atheroprotective activity relations. In parallel, molecular dynamics simulations were performed to explore the AMP conformational preferences within an aqueous environment. Notably, AMPs with ether linkages between the hydrophobic arms and sugar backbones demonstrated enhanced degradation stability and storage stability, and also elicited enhanced anti-atherogenic bioactivity. Additionally, AMPs with increased hydrophobicity elicited increased atheroprotective bioactivity in the presence of serum. These studies provide key insights for designing more serum-stable polymeric micelles as prospective cardiovascular nanotherapies.

A novel bifunctional bis(hemiacetal ester) chain transfer agent (CTA), 1,2-bis[1-(4-cyano-4-methyl-1-oxo-4-(phenylcarbonothioylthio)butanoxy)ethoxy] ethane (CMPTBEE), appropriate for the reversible addition-fragmentation chain transfer (RAFT) polymerization of methacrylate monomers, was successfully synthesized and used for the preparation of a family of 10 hydrolyzable end-linked polymer (co)networks. The family comprised three methyl methacrylate (MMA) homopolymer networks with different degrees of polymerization, 100, 150, and 200, and seven end-linked amphiphilic polymer conetworks of MMA and 2-(dimethylamino)ethyl methacrylate (DMAEMA) with a constant overall degree of polymerization equal to 200 but various compositions and architectures. The agreement of the experimentally measured molecular weights with the theoretically expected ones and the low molecular weight dispersities of the linear precursors to the (co)networks indicated successful control of the polymerization. All (co)networks were characterized in terms of their sol fraction and in terms of their degree of swelling in THF. The value of the former was found in the range between 4 and 50%, whereas that of the latter was around 13%. The presence of the hemiacetal ester groups allowed the hydrolysis of the most hydrophilic, DMAEMA-rich conetworks. The resistance to hydrolysis of the other (co)networks could be attributed to the large hydrophobic blocks surrounding and protecting from hydrolysis the hemiacetal ester groups of the CTA residue in the conetworks. © 2012 American Chemical Society. 45 19 7890 7899 Cited By :22

International audience; Aqueous mixtures containing a non-ionic surfactant (tetraethylene glycol monododecylether, C12E4), an amphiphilic polymer (poly(sodium acrylate) hydrophobically modified with azobenzene groups randomly attached along the chains, HMPA) and 0.3 M NaNO3 were studied regarding the associations between macromolecules and surfactant assemblies (micelles or lamellar phases) at various temperatures (4-37 degrees C). The effects of the thermo-induced transition of surfactant assemblies from micelles to lamellar phase on phase separation behavior were systematically investigated as a function of surfactant and polymer concentration, polymer structure (amount of grafted hydrophobic groups) and temperature. Rheological properties of polymer-rich coacervates revealed thermo-thickening behavior, in accordance with phase separation behavior. Finally, bulk phenomena were applied to design nanoemulsions with improved temperature stability taking the opportunity of strengthening interfacial layers through thermo-thickening properties. (C) 2011 Elsevier B.V. All rights reserved.

Doubly capped nanocrystals: A new technique was developed for coating of colloidal inorganic nanoparticles with different surface properties with a thin, cross-linked, and functionalized shell containing organic and inorganic layers (see picture). The underlying amphiphilic polymer foundation arranges on the particle surface as predicted in past reports Refereed/Peer-reviewed

Cationic amphiphilic polymethacrylate derivatives (PMAs) have shown potential as a novel class of synthetic antimicrobials. A panel of PMAs with varied ratios of hydrophobic and cationic side chains were synthesized and tested for antimicrobial activity and mechanism of action. The PMAs are shown to be active against a panel of pathogenic bacteria, including a drug-resistant Staphylococcus aureus, compared to the natural antimicrobial peptide magainin which did not display any activity against the same strain. The selected PMAs with 47–63% of methyl groups in the side chains showed minimum inhibitory concentrations of ≤2–31 µg/mL, but cause only minimal harm to human red blood cells. The PMAs also exhibit rapid bactericidal kinetics. Culturing Escherichia coli in the presence of the PMAs did not exhibit any potential to develop resistance against the PMAs. The antibacterial activities of PMAs against E. coli and S. aureus were slightly reduced in the presence of physiological salts. The activity of PMAs showed bactericidal effects against E. coli and S. aureus in both exponential and stationary growth phases. These results demonstrate that PMAs are a new antimicrobial platform with no observed development of resistance in bacteria. In addition, the PMAs permeabilized the E. coli outer membrane at polymer concentrations lower than their MIC values, but they did not show any effect on the bacterial inner membrane. This indicates that mechanisms other than membrane permeabilization may be the primary factors determining their antimicrobial activity.

cited By 10; International audience; Two groups of copolymers were synthesized from high molecular weight polyacrylamides. One group of copolymers consisted of sulfonated, anionic copolymers (PAM-S) of acrylamide with the sodium salt of 2-acryloamido-2-methyl-1-propane sulfonic acid, and the other consisted of zwitterionic copolymers (PAM-Z) of acrylamide with a sulfobetaine methacrylate monomer. The shear rheology of aqueous solutions of the copolymers and their mixtures was studied experimentally. Solutions of both copolymers exhibit shear thinning behavior in the range of concentrations explored. Solutions of mixtures of two copolymers (PAM-Z and PAM-S) exhibited a slight viscosity synergy at high relative contents of PAM-S. Addition of a relatively high concentration of an electrolyte (0.3. M NaCl) induces decreases in viscosity due to coil contraction and eliminates the synergy of the mixtures. Mixtures of the zwitterionic copolymer and a cationic surfactant, cetyl trimethylammonium p-toluene sulfonate (CTAT), were also studied. These solutions exhibit a strong synergistic effect at low-shear rates when the surfactant forms wormlike micelles. In addition, oscillatory shear measurements demonstrate that PAM-Z/CTAT mixtures are significantly more elastic than CTAT solutions, which indicates that PAM-Z is effective in promoting micelle entanglements, as reflected by the increase in relaxation time with PAM-Z content.

The combination of controlled anionic polymerization and subsequent introduction of hydrogen bonding groups was established to form thermo-reversible, supramolecular networks. Several polyisoprene-block-polystyrene-block-polyisoprene (ISI) copolymers&mdash, with polystyrene (PS) as the main block, and consequently giving the decisive material characteristics&mdash, were synthesized. The novel modification approach to post-functionalize the polyisoprene (PI) end-blocks and to introduce different motifs, which are able to form self-complementary hydrogen bonds, was attained. In the first step, hydroxylation was accomplished using 9-borabicyclo[3.3.1]nonane. Starting from the hydroxylated polymer, esterification with succinic anhydride was implemented to form an ester group with carboxylic end-group (-O-CO-CH2-CH2-COOH). In a second approach, 1,1&rsquo, carbonyldiimidazole was used as coupling agent to introduce various types of diamines (diethylenetriamine, triethylentetramine, and 2,6-diaminopyridine) to prepare urethane groups with amine end-group (-O-CO-NH-R-NH2). 1H NMR spectroscopy was used to confirm the successful synthesis and to calculate the degree of functionalization Df. Differential scanning calorimetry (DSC) showed a difference of the glass transition temperature Tg between unfunctionalized and functionalized block copolymers, but no greater influence between the different types of modification, and thus, on the Tg of the PS block. In temperature dependent FTIR spectroscopy, reversible processes were observed.

One-pot, sequential reversible addition - fragmentation chain transfer (RAFT) polymerization was employed for the preparation of five end-linked semifluorinated amphiphilic polymer conetworks based on 2,2,2-trifluoroethyl methacrylate (TFEMA, hydrophobic monomer) and 2-(dimethylamino)ethyl methacrylate (DMAEMA, hydrophilic monomer). 1,4-Bis[2-(thiobenzoylthio)prop-2- yl]benzene (1,4-BTBTPB) was used as the chain transfer agent, while ethylene glycol dimethacrylate (EGDMA) served as the cross-linker. Three of the end-linked conetworks were based on ABA triblock copolymers with polyDMAEMA midblocks with degrees of polymerization (DPs) of 50 and polyTFEMA end-blocks with overall polyTFEMA DPs of 25, 50, and 75. The fourth end-linked amphiphilic polymer conetwork was based on an equimolar BAB triblock copolymer with a polyTFEMA midblock and an overall copolymer DP of 100. The last end-linked conetwork was based on a statistical copolymer. A randomly cross-linked conetwork was also prepared by the simultaneous terpolymerization of the two comonomers (equimolar) and the cross-linker. The molecular weights and compositions of all the polymer precursors to the conetworks were characterized using gel permeation chromatography and 1H NMR spectroscopy, respectively. The conetworks were characterized in terms of their degrees of swelling (DS) in THF and in water as a function of the solution pH. All conetworks swelled more in acidic than in pure water due to the ionization of the DMAEMA units in acidic water. The low pH aqueous DS of the statistical copolymer-based end-linked conetwork was higher than those of its triblock copolymer counterparts due to lack of microphase separation within the former conetwork. Finally, the microphase separation of the amphiphilic conetworks in deuterium oxide was investigated using small-angle neutron scattering which indicated a distance between the hydrophobic scattering centers of about 15 nm. © 2010 American Chemical Society. 43 12 5195 5204 Cited By :22

We tested two kinds of amphiphilic polymers for cell surface modification: a poly(ethylene glycol)-conjugated phospholipid (PEG-lipid) and a poly(vinyl alcohol) that carried alkyl side chains (PVA-alkyl). Both polymers were expected to anchor to the lipid bilayer of the cell membrane through hydrophobic interactions. We followed the kinetics of these fluorescently labeled amphiphilic polymers (fPEG-lipid, fPVA-alkyl) over time on living cells with confocal scanning laser microscopy and flow cytometry. We found that fPEG-lipids and fPVA-alkyl polymers were not cytotoxic, and they were released from the cell surface without triggering endocytosis. The gradual release from the cell surface was influenced by the hydrophobicity of the alkyl chains, which affected their stability. The amphiphilic polymers tended to aggregate on the cell surface; in particular, the aggregation of PVA-alkyl was clearly identified. Although most of PEG-lipids and PVA-alkyl polymers did not appear to in the cytoplasm, the cells were able to endocytose lipid molecules, as expected. These results suggested that the retention time of modified amphiphilic polymers on the cell surface should be a consideration when modifying cell surfaces to enhance cell transplantation.

Semisegmented amphiphilic polymer conetworks (APCNs) based on the hydrophilic monomer 2-(dimethylamino)ethyl methacrylate (DMAEMA), the hydrophobic monomer methyl methacrylate (MMA), and the hydrophobic cross-linker ethylene glycol dimethacrylate (EGDMA) were prepared using group transfer polymerization in a two-step procedure that involved the synthesis of linear polyDMAEMA or polyMMA arms, followed by their cross-linking using a mixture of EGDMA with either MMA or DMAEMA, respectively. Four semisegmented APCNs with polyMMA arms with degrees of polymerization (DPs) of 10, 20, 30, and 40 and three with polyDMAEMA arms with DPs of 10, 20, and 30 were prepared. The sol fraction extracted from the APCNs, the percentage of linear polymer in the sol fraction, and the molecular weights of the branched fraction of the extractables increased as the DP of the arms increased. The degrees of swelling (DSs) in water of all semisegmented APCNs increased with decreasing pH and increasing percentage of DMAEMA hydrophilic units. Despite the rather imperfect, semisegmented placement of the dissimilar units, extensive small-angle neutron scattering (SANS) experiments in D2O indicated that nanophase organization did take place within these APCNs and persisted, in many cases, even at full ionization of the hydrophilic monomer repeating units. The SANS profiles were also used to calculate the spacings between the scattering centers, which were found to increase with the content in the DMAEMA units and their degree of ionization. © 2009 American Chemical Society. 42 8 2972 2980 Cited By :24

We investigated the microphase-separated morphologies of water-swollen amphiphilic single and double polymer networks using small-angle X-ray scattering (SAXS). The networks consist of (i) a first conetwork containing hydrophobic blocks from either 2-ethylhexyl methacrylate (EHMA) or lauryl methacylate (LauMA) and hydrophilic blocks from 2-(dimethylamino)ethyl methacrylate (DMAEMA) and (ii) a second polyacrylamide (PAAm) network. The SAXS curves are modeled by spherical core-shell micelles, where densely packed hydrophobic cores are surrounded by swollen hydrophilic chains. The correlation between these hydrophobic cores is described using a hard-sphere structure factor. A Porod law and an Ornstein-Zernike structure factor are adopted to capture the strong forward scattering due to large-scale inhomogeneities and the correlation between polymer strands, respectively. The size of the hydrophobic cores depends on the degree of polymerization of the hydrophobic block: for medium and long hydrophobic blocks, several hydrophobic cores merge together to form a larger core. When the second PAAm network is present, the nanostructures of the first amphiphilic network are less well-defined. © 2016, Springer-Verlag Berlin Heidelberg. 294 6 1027 1036 Cited By :6

Self-assembled nanoparticles have reached a growing interest for the improvement ofcancer diseases and associated inflammation processes. This article describes the mostrepresentative types of self-assembling nanosystems, including a detailed review ofdifferent methodologies for their preparation. Nanoparticles are commonly formed by self-assembling of amphiphilic polymers in aqueous environment. For that reason, the mainstrategies for the design of amphiphilic polymeric systems are also reviewed, with anemphasis on the different polymerization techniques of synthetic monomers and severalstrategies of chemical modification of polysaccharides and proteins. Additionally, mostadvanced applications of self-assembled nanocarriers for the improvement of treatmentof cancer and inflammation diseases are also discussed, focusing on the description ofdrug-loaded and drug-conjugated systems, active targeted strategies and most recentlypossibilities for the multimodality treatment of cancer diseases., Financial support from CIBER-BBN/ECO (NANOVIT) is appreciated.

In recent years, amphiphilic polymers which consist of both hydrophilic and hydrophobic groups, have become more important in the biomedical, biochemical and pharmaceutical fields due to their ability to form supramolecular structure in the aqueous solutions. In the present thesis, four novel amphiphilic chitosan polymer including different amounts of fluorescent polyimide chromophores with comb shaped structures was successfully synthesized by polycondensation reactions. The synthesized products were analyzed using FTIR, UV-vis and Fluorescence spectrocopy. Unlike the Chitosan (CS) and Perylene-3,4,9,10- tetracarboxylic dianhydride (PDA), the new products of perylene diimide conjugated chitosan polymer are soluble in most of solvents such as DMSO, DMAc and DMF. The absorption bands were shifted bathocromically in these solvents as solvent polarity increases. The fluorescence quantum yield values of A1PCH, A2PCH, A3PCH and A4PCH were found 0.44, 0.76, 0.50 and 0.56, respectively, in DMF. Among these products, while A2PCH has the highest solubility and fluorescence properties, it has the lowest aggregation. All of PCH polymers having fluorescent properties can be used in drug delivery systems. Keywords: Amphiphilic polymers, Perylene polymers, Chitosan, Solubility ÖZ: Son yıllarda, hidrofobik ve hidrofilik gruplardan oluşan amfifilik polimerler, sulu çözeltilerde süpramoleküler yapı oluşturma yeteneğinden dolayı biyomedikal, biyokimyasal ve eczacılık alanlarında büyük öneme sahiptir. Bu tezde, farklı miktarlarda floresans aromatik poliimit içeren 4 yeni amfifilik kitosan polimeri tarak şeklinde yapılar ile başarılı bir şekilde polikondensasyon reaksiyonu ile sentezlenmiştir. Sentezlenen ürünler FTIR, UV-vis ve floresans spektroskopi kullanılarak analiz edilmiştir. Kitosan (CS) ve perilen-3,4,9,10-tetrakarboksilik dianhidrit (PDA)’ in aksine, yeni perilendiimit konjuge kitosan polimerleri DMSO, NMP, DMAc ve DMF gibi bir çok organik çözücü içerisinde çözünmüşlerdir. Bu çözücülerde absorpsiyon bantları çözücü polariteleri arttıkça kırmızıya doğru kaymışlardır. DMF’te A1PCH, A2PCH, A3PCH ve A4PCH’ın floresans kuantum verimleri sırasıyla 0.44, 0.76, 0.50 and 0.56 bulunmuştur. Bu ürünler arasında, A2PCH en yüksek çözünürlük ve floresans özelliğine sahipken, en düşük aggregasyona sahiptir. Floresans özelliğe sahip bütün PCH polimerleri ilaç taşıma sistemlerinde kullanılabilir. Anahtar kelimeler: Amfifilik polimerler, Perilen polimerler, Kitosan ve Çözünürlük. Master of Science in Chemistry. Thesis (M.S.)--Eastern Mediterranean University, Faculty of Arts and Sciences, Dept. of Chemistry, 2016. Co-Supervisor: Assoc. Prof. Dr. Hamit Caner, Supervisor: Prof. Dr. Huriye İcil.

Four linear and four star equimolar terpolymers based on non-ionic hydrophilic methoxy hexa(ethylene glycol) methacrylate, ionizable hydrophilic 2-(dimethylamino)ethyl methacrylate and neutral hydrophobic methyl methacrylate were synthesized using group transfer polymerization and investigated in aqueous dilute solutions. It was found that the (ABC)n multi-arm star terpolymers formed unimolecular micelles comprising three centrosymmetric compartments. The position of each compartment could be determined by the block sequence (ABC, ACB or BAC) atwill. On the other hand, the ABC linear counterparts formed loose associates with very low aggregation numbers. It was shown that the polymer architecture (linear versus star) greatly affected the micellization phenomena of the terpolymers in selective media. © 2007 WILEY-VCH Verlag GmbH & Co. KCaA. 28 5 560 566 Cited By :26

The recent literature on chemically cross-linked amphiphilic polymer networks is reviewed. The main subjects covered are network synthesis, characterization, modeling and applications. Special mention is made to more modern methods for amphiphilic network synthesis and in particular to those involving controlled polymerization techniques. A key question regarding synthesis is which method gives the most perfect networks. On the characterization side is the issue of microphase separation of amphiphilic networks in water and the morphologies obtained in these systems, in comparison with the morphologies of amphiphilic linear block copolymers in water. Major recent advances: The most important developments of the past year in the field of amphiphilic polymer networks involved mainly new syntheses: cross-linked stars of various star architectures, cross-linked linear chains of various architectures and compositions, poly(tetrahydrofuran)- and poly(propylene fumarate)-based networks, tricomponent networks containing silicon, and cross-linked poly(acrylic acid)-grafted Pluronics. A first crude model was also developed which shows that amphiphilic networks prefer to be mostly in the microphase separated state. Extensive and systematic experimental studies on network microphase separation are yet to be performed. © 2003 Elsevier Science Ltd. All rights reserved. 8 1-2 76 85 Cited By :144

The paper describes all stages of synthesis and characterization of biocompatible CdSe-based core/shell quantum dots (QDs) and their application as fluorescent label for immunoassay. Special attention was focused on development of maleic anhydride-based amphiphilic polymers for QDs solubilization in aqueous media. In this work two PEG-amines were tried for polymer modification: monoamine Jeffamine M 1000 used previously in some researches and diamine Jeffamine ED-2003 applied for the first time for QDs solubilization. The use of different Jeffamines allows us to obtain QDs with carboxyl or amine functional groups available for conjugation. The influence of polymer composition on optical properties of the nanocrystals and their stability in aqueous solutions as well as on their conjugation with biomolecules was studied. QDs with different coatings were used as biolabels in quantitative fluorescence microtiter plate immunoassay and qualitative on-site column test. It was found that quantum dots covered with amphiphilic polymer prepared from poly(maleic anhydride-alt-1-octadecene) and Jeffamine ED-2003 retained up to 90% of their initial brightness, easily conjugated with protein and showed low non-specific adsorption. In optimized conditions the obtained QDs were successfully used for determination of mycotoxin deoxynivalenol in wheat and maize samples by fluorescence microtiter plate immunoassay with an IC50 of 220 μg kg(-1) and by on-site column test with cut-off of 500 μg kg(-1).

International audience; Antimicrobial and cell-penetrating peptides have inspired developments of abiotic membrane-active polymers that can coat, penetrate, or break lipid bilayers in model systems. Application to cell cultures is more recent, but remarkable bioactivities are already reported. Synthetic polymer chains were tailored to achieve (i) high biocide efficiencies, and selectivity for bacteria (Gram-positive/Gram-negative or bacterial/mammalian membranes), (ii) stable and mild encapsulation of viable isolated cells to escape immune systems, (iii) pH-, temperature-, or light-triggered interaction with cells. This review illustrates these recent achievements highlighting the use of abiotic polymers, and compares the major structural determinants that control efficiency of polymers and peptides. Charge density, sp. of cationic and guanidinium side groups, and hydrophobicity (including polarity of stimuli-responsive moieties) guide the design of new copolymers for the handling of cell membranes. While polycationic chains are generally used as biocidal or hemolytic agents, anionic amphiphilic polymers, including Amphipols, are particularly prone to mild permeabilization and/or intracell delivery.

International audience; Amphiphilic polymers are synthesized from various biobased compounds involving telomerization of glycerin-derived acrylate monomers with mercaptan-modified fatty acids. The effects of the chemical structure of the saturated or unsaturated hydrophobic block are investigated. Dynamic and static light scattering measurements, transmission electronic microscopy, and atomic force microscopy observations show that these copolymers are capable of self-assembling into nanosized spherical particles in aqueous solution, made from compound micelles. The critical micellar concentration of these polymers is in the range of 10-60 mg L−1 determined by fluorescence. These biobased polymers could have applications in various industrial fields, such as cosmetics and agrochemicals.

The treatment of poly( glycidyl methacrylate) with nucleophilic agents yielded new linear homo/co-polymers. The materials obtained have different physicochemical properties depending upon the nucleophiles utilized and thus, by this way, water soluble polymers are easily accessible. This approach is also very convenient for the synthesis of amphiphilic block copolymers. Additional chemical modifications can further transform the obtained polymers after the post-polymerization treatment. Starting from RAFT pre-synthesized/pre-functionalized polymers, the described procedures allow us to obtain a wide variety of chemically diverse materials characterized by controlled structure and specific functions.

International audience; Core cross‐linked amphiphilic star‐block copolymers were prepared by hydrolysis of the outer shell of star‐block copolymers prepared using copper mediated atom transfer radical polymerization (ATRP). In an arm‐first approach, linear poly(tert‐butyl methacrylate) macroinitiators (Pt BMA‐Cl) were extended with styrene to yield Pt BMA‐b‐PS‐Cl and then cross‐linked with divinylbenzene (DVB) in order to yield (Pt BMA‐b‐ PS)arms‐PDVBcore star‐block copolymers. Then, PMAA‐b‐ PS block and (PMAA‐PS)arms‐PDVBcore star‐block copolymers were obtained by hydrolysis of the Pt BMA blocks in both linear and cross‐linked copolymers, as confirmed by 1H NMR analyses. The amphiphilic character of these copolymers was confirmed by solubilisation in water. Several factors affecting the polymer aggregation and solubility such as the length, the composition of the arms and the catalyst used were studied. An acrylate analogue, that is, (PAA‐b‐ PS)arms‐PDVBcore, was also prepared for comparison purposes. Atomic force microscopy (AFM) and differential scanning calorimetry (DSC) were used to elucidate the morphology and the thermal behaviour of the star‐block copolymers.