A Miscibility Study of p(MMA--HEMA)-Based Polymer Blends by Thermal Analysis and Solid-State NMR Relaxometry.

Ternary amorphous solid dispersions (ASDs) consist of a multicomponent carrier with the aim of improving physical stability or dissolution performance. A polymer blend as a carrier that combines a water-insoluble and a water-soluble polymer may delay the drug release rate, minimizing the risk of precipitation from the supersaturated state. Different microstructures of the ternary ASD may result in different drug release performances; hence, understanding the phase morphology of the polymer blend is crucial prior to drug incorporation.

A Spontaneous In Situ Thiol-Ene Crosslinking Hydrogel with Thermo-Responsive Mechanical Properties.

The thermo-responsive behavior of Poly(N-isopropylacrylamide) makes it an ideal candidate to easily embed cells and allows the polymer mixture to be injected. However, P(NiPAAm) hydrogels possess minor mechanical properties. To increase the mechanical properties, a covalent bond is introduced into the P(NIPAAm) network through a biocompatible thiol-ene click-reaction by mixing two polymer solutions.

Carbon nanotubes as a nitric oxide nano-reservoir improved the controlled release profile in 3D printed biodegradable vascular grafts.

Small diameter vascular grafts (SDVGs) are associated with a high failure rate due to poor endothelialization. The incorporation of a nitric oxide (NO) releasing system improves biocompatibility by using the NO effect to promote endothelial cell (EC) migration and proliferation while preventing bacterial infection. To circumvent the instability of NO donors and to prolong NO releasing, S-nitroso-N-acetyl-D-penicillamine (SNAP) as a NO donor was loaded in multi-walled carbon nanotubes (MWCNTs).

Gastro-resistant encapsulation of amorphous solid dispersions containing darunavir by coaxial electrospraying.

The relatively simple technique of coaxial electrospraying allows to produce core-shell microparticles with potentially high encapsulation efficiencies. In this study, amorphous solid dispersions of a hydroxypropyl methylcellulose or polyvinlypyrrolidone based polymer matrix containing the active pharmaceutical ingredient darunavir were coated with a gastro-resistant shell polymer that does not dissolve at lower pH present in the stomach, but only later at a higher pH in the small intestine. A multitude of shell polymers were tested with the aim to identify a material that limits the drug release to less than 10% after two hours at a pH of 1 to comply with the European Pharmacopoeia regarding gastro-resistant formulations.

Synthesis, Characterization and Cytotoxicity of Novel Thermoresponsive Star Copolymers of ,'-Dimethylaminoethyl Methacrylate and Hydroxyl-Bearing Oligo(Ethylene Glycol) Methacrylate.

Novel, nontoxic star copolymers of ,-dimethylaminoethyl methacrylate (DMAEMA) and hydroxyl-bearing oligo(ethylene glycol) methacrylate (OEGMA-OH) were synthesized via atom transfer radical polymerization (ATRP) using hyperbranched poly(arylene oxindole) as the macroinitiator. Stars with molar masses from 100,000 g/mol to 257,000 g/mol and with various amounts of OEGMA-OH in the arms were prepared. As these polymers can find applications, e.

Synthesis and post-functionalization of alternate-linked-[2 .1 ]thiacyclophanes.

In recent decades, considerable research attention has been devoted to new synthetic procedures for thiacyclophanes. Thiacyclophanes are widely used as host molecules for the molecular recognition of organic compounds as well as metals. Herein, we report the selective and high-yielding synthesis of novel alternate-linked-thiacyclophanes.

Saturation reduces in-vitro leakage of monomers from composites.

Objective: Accurate knowledge of the quantity of released monomers from composites is important. To evaluate the elution of monomers, polymerized composites are typically immersed in an extraction solvent. The objective was to determine whether the volume of extraction solvent and the immersion time influences monomer leachability from dental composite materials.

Stable star polymer nanolayers and their thermoresponsiveness as a tool for controlled culture and detachment of fibroblast sheets.

In this study, we describe novel thermoresponsive star copolymer surfaces used for the first time for the culture of fibroblast sheets, followed by their detachment, controlled by a change in temperature. To date, no star polymers, or their layers, have been used for this purpose. A "grafting to" strategy was applied to obtain poly[oligo(ethylene glycol) methacrylate] star layers on functionalized solid supports.

Acid-Sensitive BODIPY Dyes: Synthesis through Pd-Catalyzed Direct C(sp )-H Arylation and Photophysics.

A novel palladium-catalyzed direct C(sp )-H arylation of the methyl group at the 8-position of BODIPY by bromoarenes was established. A deprotonative cross-coupling process was supposed to be involved in the reaction. This approach allowed us to attach electron-donating/withdrawing, halogen substituted aryls and a heteroaryl with a yield running from 55 to 99 %.

Simultaneous analysis of bisphenol A based compounds and other monomers leaching from resin-based dental materials by UHPLC-MS/MS.

Resin-based dental materials have raised debates concerning their safety and biocompatibility, resulting in a growing necessity of profound knowledge on the quantity of released compounds into the oral cavity. In this context, the aim of this study was to develop a comprehensive and reliable procedure based on liquid chromatography with mass spectrometry for the simultaneous analysis of various leached compounds (including bisphenol A based compounds) in samples from in vitro experiments. Different experiments were performed to determine the optimal analytical parameters, comprising mass spectrometry parameters, chromatographic separation conditions, and sample preparation.

Water-soluble sulfonated hyperbranched poly(arylene oxindole) catalysts as functional biomimics of cellulases.

A new polymer acid catalyst, sulfonated hyperbranched poly(arylene oxindole), 5-OH-SHPAO, was prepared for selective cellulose hydrolysis. Its superior catalysis, showing high glucose selectivity at almost full cellulose conversion, is attributed to the presence of an hydroxyl group next to the sulfonic acid, therefore mimicking the separate acid-base pair in the cellulase active site.

Poly(alanine): Structure and Stability of the D and L-Enantiomers.

High-performance, biobased materials can potentially be manufactured from polymerized α-amino acids (α-polypeptides). This paper reports on the synthesis, structure, and properties of both polyalanine enantiomers (PLAla and PDAla). The molecular structure of the polypeptide chains, their molecular weight, and polydispersity were investigated by (1)H NMR, MALDI-TOF, and size-exclusion chromatography.

Homodiselenacalix[4]arenes: Molecules with Unique Channelled Crystal Structures.

A synthetic route towards homodiselenacalix[4]arene macrocycles is presented, based on the dynamic covalent chemistry of diselenides. The calixarene inner rim is decorated with either alkoxy or tert-butyl ester groups. Single-crystal X-ray analysis of two THF solvates with methoxy and ethoxy substituents reveals the high similarity of their molecular structures and alterations on the supramolecular level.

Selenium-Platinum Coordination Dendrimers with Controlled Anti-Cancer Activity.

Dendrimers are considered as good vectors for drug delivery in cancer treatment. However, most anticancer drugs are conjugated to the peripheral surface of dendrimers, sacrificing the advantages of monodispersity and stability belonging to dendrimers. Furthermore, dendrimers in current studies of cancer treatment are mostly used as vectors for drugs, whereas the anticancer activity of dendrimers on their own is less studied.

Nonviral Plasmid DNA Carriers Based on N,N'-Dimethylaminoethyl Methacrylate and Di(ethylene glycol) Methyl Ether Methacrylate Star Copolymers.

Star polymers with random and block copolymer arms made of cationic N,N'-dimethylaminoethyl methacrylate (DMAEMA) and nonionic di(ethylene glycol) methyl ether methacrylate (DEGMA) were synthesized via atom transfer radical polymerization (ATRP) and used for the delivery of plasmid DNA in gene therapy. All stars were able to form polyplexes with plasmid DNA. The structure and size of the polyplexes were precisely determined using light scattering and cryo-TEM microscopy.

Highly efficient hyperbranched CNT surfactants: influence of molar mass and functionalization.

End-group-functionalized hyperbranched polymers were synthesized to act as a carbon nanotube (CNT) surfactant in aqueous solutions. Variation of the percentage of triphenylmethyl (trityl) functionalization and of the molar mass of the hyperbranched polyglycerol (PG) core resulted in the highest measured surfactant efficiency for a 5000 g/mol PG with 5.6% of the available hydroxyl end-groups replaced by trityl functions, as shown by UV-vis measurements.

Importance of thiol-functionalized molecules for the structure and properties of compression-molded glassy wheat gluten bioplastics.

High-temperature compression molding of wheat gluten at low water levels yields a rigid plastic-like material. We performed a systematic study to determine the effect of additives with multiple thiol (SH) groups on gluten network formation during processing and investigate the impact of the resulting gluten network on the mechanical properties of the glassy end product. To this end, a fraction of the hydroxyl groups of different polyols was converted into SH functionalities by esterifying with 3-mercaptopropionic acid (MPA).

Impact of acid and alkaline pretreatments on the molecular network of wheat gluten and on the mechanical properties of compression-molded glassy wheat gluten bioplastics.

Wheat gluten can be converted into rigid biobased materials by high-temperature compression molding at low moisture contents. During molding, a cross-linked protein network is formed. This study investigated the effect of mixing gluten with acid/alkali in 70% ethanol at ambient temperature for 16 h followed by ethanol removal, freeze-drying, and compression molding at 130 and 150 °C on network formation and on types of cross-links formed.

Selenium/Tellurium-Containing Hyperbranched Polymers: Effect of Molecular Weight and Degree of Branching on Glutathione Peroxidase-Like Activity.

A series of novel hyperbranched polyselenides and polytellurides with multiple catalytic sites at the branching units has been synthesized via the polycondensation of A2 + B3 monomers. The GPx-like activities of these polymer mimics were assessed and it was found that the polytellurides showed higher GPx-like activities than the corresponding polyselenides. Interestingly, the polymers with higher molecular weights and degree of branching (DB) showed higher GPx-like activities than the analogous lower molecular weight polymer.

Homoselenacalix[4]arenes: synthetic exploration and metallosupramolecular chemistry.

Homoselenacalix[4]arenes were synthesized by a [2 + 2] reductive coupling protocol favouring the cyclotetramers. The inner and outer-rim decoration was varied and a bicyclic derivative was prepared by a similar one-pot procedure. Conformational analysis in solution and the solid state showed noticeable differences between the homoselenacalix[4]arenes and the analogous homothiacalix[4]arenes and provided insight into the metal binding potential of the Se-bridged macrocycles.

Fully-branched hyperbranched polymers with a diselenide core as glutathione peroxidase mimics.

A novel glutathione peroxidase (GPx) mimic has been prepared by incorporation of a selenium-based catalytic unit into the focal point of a fully-branched hyperbranched polymer. First, an AB(2) monomer consisting of isatin and an electron rich aromatic moiety was polycondensed in the presence of 5-nitroisatin as a core reagent, resulting in a polymer with 100% degree of branching. The latter was coupled to the catalytically active moiety, Br(CH(2))(5) SeSe(CH(2))(5) Br, by nucleophilic substitution of the bromides by the residual amide groups of the incorporated nitroisatin core.

Bolaamphiphiles bearing bipyridine as mesogenic core: rational exploitation of molecular architectures for controlled self-assembly.

A bolaamphiphile (5,5-B2NBr8) bearing a functional bipyridine moiety as the mesogenic core is reported for the first time. 5,5-B2NBr8 was found to self-assemble into uniform fibrous structure in aqueous solution, when the concentration was higher than cmc. Analogues of 5,5-B2NBr8 with structural differences in chain length, headgroup, mesogenic core, and substituted position were synthesized, elucidating that small variances of the molecular structure could lead to dramatic changes of the resulting assemblies.

Thiol-promoted catalytic synthesis of diphenolic acid with sulfonated hyperbranched poly(arylene oxindole)s.

Acid-catalyzed condensation of levulinic acid and phenol into high yields of diphenolic acid (>50%) is possible with a combination of sulfonated hyperbranched polymers and thiol promotors, either added as a physical mixture or bound to the polymer by ion-pairing.

UV-responsive polymeric superamphiphile based on a complex of malachite green derivative and a double hydrophilic block copolymer.

We have prepared a UV-responsive polymeric superamphiphile, formed by a malachite green derivative and the double hydrophilic block copolymer methoxy-poly(ethylene glycol)(114)-block-poly(l-lysine hydrochloride)(200) (PEG-b-PLKC) on the basis of electrostatic interactions. The malachite green derivative undergoes photo-ionization upon UV irradiation, which makes it more hydrophilic, resulting in changes in the self-assembly behavior of the polymeric superamphiphile. For this reason, the polymeric superamphiphile originally self-assembles to form sheetlike aggregates, which disassemble after UV irradiation because of the increased solubility of the malachite green derivative.