Luminescent SiO2 nanoparticles for cell labeling: combined water dispersion polymerization and 3D condensation controlled by oligoperoxide surfactant-initiator

Hybrid polymer coated silica nanoparticles (NPs) were synthesized using low temperature graft (co)polymerization of trimethoxysilane propyl methacrylate (MPTS) initiated by surface-active oligoperoxide metal complex (OMC) in aqueous media. These NPs were characterized by means of kinetic, solid-state NMR, TEM and FTIR techniques. Two processes, namely the radical graft-copolymerization due to presence of double bonds and 3D polycondensation provided by the intra- or/and intermolecular interaction of organosilicic fragments, occurred simultaneously. The relative contribution of the reactions depending on initiator concentration and pH value leading to the formation of low cured polydisperse microparticles or OMC coated SiO2 NPs of controlled curing degree was studied. The availability of free-radical forming peroxide fragments on the surface of SiO2 NPs provides an opportunity for seeded polymerization leading to the formation of the functional polymer coated NPs with controlled particle structure, size, and functionality. Encapsulation of the luminescent dye (Rhodamine 6G) in SiO2 core of functionalized NPs provided a noticeable increase in their resistance to photo-bleaching and improved biocompatibility. These luminescent NPs were not only attached to murine leukemia L1210 cells but also tolerated by the mammalian cells. Their potential use for labeling of the mammalian cells is considered

Особенности технологии изготовления клеев для гофрокартона

Досліджено клейові композиції на основі різних крохмалів і показано, їх вплив на якість готового продукту.Investigational glue compositions on the basis of different starches and it is rotined, their influence on quality of the prepared product.Исследованы клеевые композиции на основе разных крахмалов и показано, их влияние на качество готового продукта

Diastereospecific Bis-alkoxycarbonylation of 1,2-Disubstituted Olefins Catalyzed by Aryl α-Diimine Palladium(II) Catalysts

Readily synthesized aryl α-diimine derivatives have been used as efficient ligands for the palladium-catalyzed oxidative bis-alkoxycarbonylation reaction of 1,2-disubstituted olefins. The most active catalyst A was formed in situ from bis-(2,6-dimethylphenyl)-2,3-dimethyl-1,4-diazabutadiene and Pd(TFA)2 (TFA=trifluoroacetate). This catalytic system was able to selectively convert 1,2-disubstituted olefins into 2,3-disubstituted-succinic diesters with total diastereospecificity, in good yields (up to 97%) with 2 mol% of catalyst loading, under mild reaction conditions (4 bar of CO at 20 °C in presence of p- toluenesulfonic acid as additive and p-benzoquinone as oxidant). The optimized reaction conditions could be successfully applied to 1,2-disubstituted aromatic, aliphatic, cyclic olefins and to unsaturated fatty acid methyl esters, employing methanol or benzyl alcohol as nucleophiles. The use of the bulky, less reactive isopropyl alcohol has allowed to better understand the mechanisms involved in the catalytic process. The geometry of the carbonylated products can be explained as a consequence of a concerted syn addition of the Pd-alkoxycarbonyl moiety to the olefin C=C bond. Catalyst A was isolated, characterized and analyzed by single crystal X-ray diffraction analysis. (Figure presented.)

Amphiphilic Invertible Polymers: Self-Assembly into Functional Materials Driven by Environment Polarity

Stimuli-responsive polymers adapt to environmental changes by adjusting their chain conformation in a fast and reversible way. Responsive polymeric materials have already found use in electronics, coatings industry, personal care, and bio-related areas. The current work aims at the development of novel responsive functional polymeric materials by manipulating environment-dependent self-assembly of a new class of responsive macromolecules strategically designed in this study, – amphiphilic invertible polymers (AIPs). Environment-dependent micellization and self-assembly of three different synthesized AIP types based on poly(ethylene glycol) as a hydrophilic fragment and varying hydrophobic constituents was demonstrated in polar and nonpolar solvents, as well as on the surfaces and interfaces. With increasing concentration, AIP micelles self-assemble into invertible micellar assemblies composed of hydrophilic and hydrophobic domains. Polarity-responsive properties of AIPs make invertible micellar assemblies functional in polar and nonpolar media including at interfaces. Thus, invertible micellar assemblies solubilize poorly soluble substances in their interior in polar and nonpolar solvents. In a polar aqueous medium, a novel stimuli-responsive mechanism of drug release based on response of AIP-based drug delivery system to polarity change upon contact with the target cell has been established using invertible micellar assemblies loaded with curcumin, a phytochemical drug. In a nonpolar medium, invertible micellar assemblies were applied simultaneously as nanoreactors and stabilizers for size-controlled synthesis of silver nanoparticles stable in both polar and nonpolar media. The developed amphiphilic nanosilver was subsequently used as seeds to promote anisotropic growth of CdSe semiconductor nanoparticles that have potential in different applications ranging from physics to medicine. Amphiphilic invertible polymers were shown to adsorb on the surface of silica nanoparticles strongly differing in polarity. AIP modified silica nanoparticles are able to adsolubilize molecules of poorly water-soluble 2-naphthol into the adsorbed polymer layer. The adsolubilization ability of adsorbed invertible macromolecules makes AIP-modified silica nanoparticles potentially useful in wastewater treatment or biomedical applications. Finally, the invertible micellar assemblies were used as functional additives to improve the appearance of electrospun silicon wires based on cyclohexasilane, a liquid silicon precursor. AIP-assisted fabrication of silicon wires from the liquid cyclohexasilane precursor has potential as a scalable method for developing electronic functional materials

Surface Active MonomersSynthesis, Properties, and Application /

XV, 67 p. 39 illus., 1 illus. in color.online res

Solvent-Responsive Self-Assembly of Amphiphilic Invertible Polymers Determined with SANS

Amphiphilic invertible polymers (AIPs) are a new class of macromolecules that self-assemble into micellar structures and rapidly change structure in response to changes in solvent polarity. Using small-angle neutron scattering (SANS) data, we obtained a quantitative description of the invertible micellar assemblies (IMAs). The detailed composition and size of the assemblies (including the effect of temperature) were measured in aqueous and toluene polymer solutions. The results show that the invertible macromolecules self-assemble into cylindrical core–shell micellar structures. The composition of the IMAs in aqueous and toluene solutions was used to reveal the inversion mechanism by changing the polarity of the medium. Our experiments demonstrate that AIP unimers self-assemble into IMAs in aqueous solution, predominantly through interactions between the hydrophobic moieties of macromolecules. The hydrophobic effect (or solvophobic interaction) is the major driving force for self-assembly. When the polarity of the environment is changed from polar to nonpolar, poly­(ethylene glycol) (PEG) and aliphatic dicarboxylic acid fragments of AIP macromolecules tend to replace each other in the core and the shell of the IMAs. However, neither the interior nor the exterior of the IMAs consists of fragments of a single component of the macromolecule. In aqueous solution, with the temperature increasing from 15 to 35 °C, the IMAs’ mixed core from aliphatic dicarboxylic acid and PEG moieties and PEG-based shell change the structure. As a result of the progressive dehydration of the macromolecules, the hydration level (water content) in the micellar core decreases at 25 °C, followed by dehydrated PEG fragments entering the interior of the IMAs when the temperature increases to 35 °C

Fluorine-containing polyamphiphiles of block structure constructed of synthetic and biopolymer blocks

Aim. Purposeful preparation of polymeric surfactants combining hydrophobic fluorine-containing and hydrophilic synthetic and natural blocks via radical and non-radical reactions using peroxide, epoxide and/or amino- terminal groups of the polymeric elementary blocks. Methods. Radical and non-radical condensation reactions, polymerization, spectral (NMR- and luminescence spectroscopy), gel-permeation chromatography and other analytical techniques`. Results. Primary oligomers poly(F-MA)-MP were synthesized via radical polymerization of fluorine-alkyl methacrylate (F-MA) in the presence of peroxide-containing telogen (MP). That provides controlling the oligomer chain length and architectures as well as entering a terminal peroxide group in the macromolecules. Radical polymerization of vinyl pyrrolidone (NVP) initiated by poly(F-MA)-MP as macroinitiator in the presence of epoxide-containing derivative of cumene (CGE) was used for obtaining water soluble poly(F-MA)-block-poly(NVP)-CGE. Finally oligonucleotide (ONC) was attached via condensation reaction of ONC primary amino group with terminal epoxide group of poly(F-MA)-block-poly(NVP)-CGE. Conclusions. A series of novel block/comb-like copolymers with synthetic and natural parts was synthesized. Obtained tri-block copolymers can be used as markers for labeling bacteria and pathological items including cancer cells.Мета. Цілеспрямоване одержання полімерних поверхнево-активних речовин, які поєднюють гідрофобні фторвмісні та гідрофільні синтетичні та натуральні блоки, за допомогою радикальних та нерадикальних конденсаційних реакцій з використанням пероксидних, епоксидних, та/або аміно- кінцевих груп у складі полімерних елементарних блоків. Методи. радикальні та нерадикальні реакції, полімеризація, спектральні (ЯМР- та люмінесцентна спектроскопія), гель-проникна хроматографія та інші аналітичні техніки. Результати. Первинні олігомери полі(F-MA)-MП синтезували шляхом радикальної полімеризації фтор-алкіл метакрилату (F-MA) у присутності пероксидвмісного телогену (MП). Використання МП забезпечує контроль довжини та структури олігомерних ланцюгів, а також входження кінцевої пероксидної групи до складу макромолекул. Радикальна полімеризація N-вінілпіролідону (NВП), ініційована полі(F-MA)-MП як макроініціатором, у присутності епоксидвмісної похідної кумолу (КГЕ) була використана для отримання водорозчинного полі(F-MA)-блок-полі(NВП)-КГЕ. В кінцевому результаті, приєднання олігонуклеотиду (ОНК) до полімерного носія було здійснено реакцією конденсації первинної аміногрупи ОНК з кінцевою епоксидною групою полі(F-MA)-блок-полі(NВП) –КГЕ. Висновки. Синтезовано серію нових блок-кополімерів, що поєднюють синтетичні та біополімери. Отримані триблок-кополімери можуть бути використані в якості маркерів для мічення бактерій та патологічних, включаючи ракові, клітин.Цель. Целенаправленное получение полимерных поверхностно-активных веществ, сочетающих фторированные гидрофобные и гидрофильные синтетические и натуральные блоки, методами радикальных и нерадикальных конденсационных реакций с использованием концевых пероксидных, эпоксидных и/или амино- групп первичных полимерных блоков. Методы. Радикальные и нерадикальные реакции, полимеризация, спектральная (ЯМР- и люминесцентная спектроскопия), гель-проникающая хроматография и другие аналитические методы. Результаты. Первичные олигомеры поли(F-MA)-MП синтезировали путем радикальной полимеризации фтор-алкилметакрилата (F-MA) в присутствии пероксидсодержащего телогена (МП). Использование МП обеспечивает контроль длины и архитектуры олигомерной цепи, а также введение концевой пероксидной группы в состав макромолекул. Радикальная полимеризация N-винилпирролидона (NВП) в присутствии эпоксидсодержащей производной кумола (КГЭ), инициируемая макроинициатором поли(F-MA)-MП, была применена для получения водорастворимого поли(F-MA)-блок-поли(NВП)-КГЭ. Наконец, олигонуклеотид (ОНК) был присоединен к полимерному носителю посредством реакции конденсации первичной аминогруппы ОНК с концевой эпоксидной группой поли(F-MA)-блок-поли(NВП)-КГЭ. Выводы. Синтезирован ряд новых блок-сополимеров сочетающих синтетические и биополимеры. Полученные триблок-сополимеры могут быть использованы как маркеры для мечения бактерий и патологических, в том числе раковых, клеток