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Hydrophilic oxygen permeable polymers - BAUSCH …

Biofilms are increasingly recognized as playing a major role in human infectious diseases, as they can form on both living tissues and abiotic surfaces, with serious implications for applications that rely on prolonged exposure to the body such as implantable biomedical devices or catheters. Therefore, there is an urgent need to develop improved therapeutics to effectively eradicate unwanted biofilms. Recently, the biological signaling molecule nitric oxide (NO) was identified as a key regulator of dispersal events in biofilms. In this paper, we report a new class of core cross-linked star polymers designed to store and release nitric oxide, in a controlled way, for the dispersion of biofilms. First, core cross-linked star polymers were prepared by reversible addition–fragmentation chain transfer polymerization (RAFT) via an arm first approach. Poly(oligoethylene methoxy acrylate) chains were synthesized by RAFT polymerization, and then chain extended in the presence of 2-vinyl-4,4-dimethyl-5-oxazolone monomer (VDM) with N,N-methylenebis(acrylamide) employed as a cross-linker to yield functional core cross-linked star polymers. Spermine was successfully attached to the star core by reaction with VDM. Finally, the secondary amine groups were reacted with NO gas to yield NO-core cross-linked star polymers. The core cross-linked star polymers were found to release NO in a controlled, slow delivery in bacterial cultures showing great efficacy in preventing both cell attachment and biofilm formation in Pseudomonas aeruginosa over time via a nontoxic mechanism, confining bacterial growth to the suspended liquid.

31/03/1993 · Hydrophilic oxygen permeable polymers ..

: Biofilms are increasingly recognized as playing a major role in human infectious diseases, as they can form on both living tissues and abiotic surfaces, with serious implications for applications that rely on prolonged exposure to the body such as implantable biomedical devices or catheters. Therefore, there is an urgent need to develop improved therapeutics to effectively eradicate unwanted biofilms. Recently, the biological signaling molecule nitric oxide (NO) was identified as a key regulator of dispersal events in biofilms. In this paper, we report a new class of core cross-linked star polymers designed to store and release nitric oxide, in a controlled way, for the dispersion of biofilms. First, core cross-linked star polymers were prepared by reversible addition–fragmentation chain transfer polymerization (RAFT) via an arm first approach. Poly(oligoethylene methoxy acrylate) chains were synthesized by RAFT polymerization, and then chain extended in the presence of 2-vinyl-4,4-dimethyl-5-oxazolone monomer (VDM) with N,N-methylenebis(acrylamide) employed as a cross-linker to yield functional core cross-linked star polymers. Spermine was successfully attached to the star core by reaction with VDM. Finally, the secondary amine groups were reacted with NO gas to yield NO-core cross-linked star polymers. The core cross-linked star polymers were found to release NO in a controlled, slow delivery in bacterial cultures showing great efficacy in preventing both cell attachment and biofilm formation in Pseudomonas aeruginosa over time via a nontoxic mechanism, confining bacterial growth to the suspended liquid.

2-Phenyl-5(4H)-oxazolone - MDPI - Publisher of Open …

27/11/2008 · We found that dodecatungstophosphoric acid (H3PW12O40), samarium and ..

Controlled/living radical polymerization techniques have transformed polymer chemistry in the last few decades, affording the production of polymers with precise control over both molecular weights and architectures. It is now possible to synthesize almost an infinite variety of macromolecules using nonspecialized equipment, finding applications in high-tech industry. However, they have several shortcomings. Until recently, living radical polymerizations could not be controlled by an external stimulus, such as visible light, pH, mechanical, chemical, etc. Moreover, they are usually sensitive to trace amounts of oxygen in the system. In this Article, we report a photoinduced living polymerization technique, which is able to polymerize a large range of monomers, including conjugated and unconjugated monomers, using ultralow concentrations of an iridium-based photoredox catalyst (typically 1 ppm to monomers) and a low energy visible LED as the light source (1–4.8 W, λmax = 435 nm). The synthesis of homopolymers with molecular weights ranging from 1000 to 2 000 000 g/mol was successfully achieved with narrow molecular weight distributions (Mw/Mn N-vinyl pyrrolidinone), poly(vinyl ester)s, and poly(acrylate)s were performed to prepare diblock copolymers. The reusability of the catalyst was demonstrated by the synthesis of a decablock polymer by multiple chain extensions. Most importantly, this process was employed to prepare well-defined polymers and multiblock copolymers in the presence of air.

We report a versatile synthetic method for the in situ self-assembly of magnetic-nanoparticle-functionalized polymeric nanomorphologies, including spherical micelles and rod-like and worm-like micelles and vesicles. Poly(oligoethylene glycol methacrylate)-block-(methacrylic acid)-block-poly(styrene) (POEGMA-b-PMAA-b-PST) triblock copolymer chains were simultaneously propagated and self-assembled via a polymerization-induced self-assembly (PISA) approach. Subsequently, the carboxylic acid groups in the copolymers were used to complex an iron ion (FeII/FeIII) mixture. Iron oxide nanoparticles were then formed in the central block, within the polymeric nanoparticles, via alkaline coprecipitation of the iron(II) and (III) salts. Nanoparticle morphologies, particle sizes, molecular weights, and chemical structures were then characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), size exclusion chromatography (SEC), and 1H NMR measurements. TEM micrographs showed that the average size of the magnetic nanoparticles was ∼7 nm at the hydrophobic/hydrophilic nexus contained within the nanoparticles. In addition, XRD was used to confirm the formation of iron oxide nanoparticles. Importantly, the polymeric nanoparticle morphologies were not affected by the coprecipitation of the magnetic nanoparticles. The hybrid nanoparticles were then evaluated as negative MRI contrast agents, displaying remarkably high transverse relaxivities (r2, greater than 550 mM–1 s–1 at 9.4 T); a result, that we hypothesize, ensues from iron oxide nanoparticle clustering at the hydrophobic–hydrophilic interface. This simple synthetic procedure is highly versatile and produces nanocarriers of tunable size and shape with high efficacy as MRI contrast agents and potential utility as theranostic delivery vectors.

synthesis of 2-phenyl-5(4H)oxazolone ..

: Controlled/living radical polymerization techniques have transformed polymer chemistry in the last few decades, affording the production of polymers with precise control over both molecular weights and architectures. It is now possible to synthesize almost an infinite variety of macromolecules using nonspecialized equipment, finding applications in high-tech industry. However, they have several shortcomings. Until recently, living radical polymerizations could not be controlled by an external stimulus, such as visible light, pH, mechanical, chemical, etc. Moreover, they are usually sensitive to trace amounts of oxygen in the system. In this Article, we report a photoinduced living polymerization technique, which is able to polymerize a large range of monomers, including conjugated and unconjugated monomers, using ultralow concentrations of an iridium-based photoredox catalyst (typically 1 ppm to monomers) and a low energy visible LED as the light source (1–4.8 W, ?max = 435 nm). The synthesis of homopolymers with molecular weights ranging from 1000 to 2?000?000 g/mol was successfully achieved with narrow molecular weight distributions (Mw/Mn N-vinyl pyrrolidinone), poly(vinyl ester)s, and poly(acrylate)s were performed to prepare diblock copolymers. The reusability of the catalyst was demonstrated by the synthesis of a decablock polymer by multiple chain extensions. Most importantly, this process was employed to prepare well-defined polymers and multiblock copolymers in the presence of air.

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