189324-13-8Relevant articles and documents
Multiwalled carbon nanotubes grafted with hyperbranched polymer shell via SCVP
Hong, Chun-Yan,You, Ye-Zi,Wu, Decheng,Liu, Ye,Pan, Cai-Yuan
, p. 2606 - 2611 (2005)
A self-condensing vinyl polymerization (SCVP) strategy via atom transfer radical polymerization (ATRP) was employed to grow hyperbranched macromolecules on the surfaces of multiwalled carbon nanotubes (MWNTs). The MWNT surface fixed with ATRP initiators [MWNT-COOCH2CH2OCOC-(CH 3)2Br, MWNT-Br] was prepared by reaction of MWNT-COCl with excess of 2-hydroxyethyl 2-bromoisobutyrate. Then, using the MWNT-Br as polyfunctional initiator (B*f), hyperbranched macromolecules were covalently grafted on MWNTs by self-condensing vinyl polymerization of 2-((bromobutyryl)oxy)ethyl acrylate (BBEA, AB* inimer) via the ATRP process. The resultant products were characterized by PT-IR, NMR, and TEM. TGA measurements showed that the weight ratio of the as-grown hyperbranched polymers on the MWNT surfaces reached 80%. The as-prepared MWNTs grafted with hyperbranched polymers exhibit relatively good dispersibility in organic solvents such as THF and chloroform.
Synthesis and physicochemical characterization of amphiphilic triblock copolymer brush containing pH-sensitive linkage for oral drug delivery
Yang, You Qiang,Lin, Wen Jing,Zhao, Bin,Wen, Xiu Fang,Guo, Xin Dong,Zhang, Li Juan
, p. 8251 - 8259 (2012)
A novel and well-defined pH-sensitive amphiphilic triblock copolymer brush poly(lactide)-b-poly(methacrylic acid)-b-poly(poly(ethylene glycol) methyl ether monomethacrylate) (PLA-b-PMAA-b-PPEGMA) and its self-assembled micelles were developed for oral administration of hydrophobic drugs. The copolymer and its precursors were synthesized by the combination of activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) and ring-opening polymerization (ROP) techniques. The molecular structures and characteristics were confirmed by GPC, 1H NMR, and FT-IR. The critical micelle concentration (CMC) values of PLA-b-PMAA-b-PPEGMA in aqueous medium varied from 1.4 to 2.6 mg/L, and the partition equilibrium constant (Kv) of pyrene in micellar solutions ranged from 2.873 × 105 to 3.312 × 105. The average sizes of the self-assembled blank and drug-loaded micelles were 140-250 nm determined by DLS in aqueous solution. The morphology of the micelles was found to be spherical by SEM. Nifedipine (NFD), a poorly water-soluble drug, was selected as the model drug and wrapped into the core of micelles via dialysis method. The in vitro release behavior of NFD from the micelles was pH-dependent. In simulated gastric fluid (SGF, pH 1.2), the cumulative release percent of NFD was relative low, while in simulated intestinal fluid (SIF, pH 7.4), more than 96% was released within 24 h. All the results showed that the pH-sensitive PLA-b-PMAA-b-PPEGMA micelle may be a prospective candidate as oral drug delivery carrier for hydrophobic drugs with controlled release behavior.
Toward the syntheses of universal ligands for metal oxide surfaces: Controlling surface functionality through click chemistry
White, Meghann A.,Johnson, Jeremiah A.,Koberstein, Jeffrey T.,Turro, Nicholas J.
, p. 11356 - 11357 (2006)
A new means for functionalizing metal oxide surfaces, specifically nanoparticles, is demostrated. This process involves the design of stable ligands that bind strongly to the surface of metal oxides and can undergo further chemical modification via click chemistry, with both small molecules as well as polymers, to yield metal oxide surfaces with tailored functionality. The nanoparticles are stable and easily dispersed in both polar and nonpolar solvents, a property that is controlled by the ligand. The resultant nanoparticles were characterized by TEM, TGA, FTIR, and NMR. Copyright
Mucus-responsive functionalized emulsions: Design, synthesis and study of novel branched polymers as functional emulsifiers
Cauldbeck, Helen,Chambon, Pierre,Edwards, Stephanie E.,Flynn, Sean,Hobson, James J.,Rannard, Steve P.
, p. 30463 - 30475 (2020)
Mucus lines the moist cavities throughout the body, acting as barrier by protecting the underlying cells against the external environment, but it also hinders the permeation of drugs and drug delivery systems. As the rate of diffusion is low, the development of a system which could increase retention time at the mucosal surface would prove beneficial. Here, we have designed a range of branched copolymers to act as functional mucus-responsive oil-in-water emulsifiers comprising the hydrophilic monomer oligo(ethylene glycol) methacrylate and a hydrophobic dodecyl initiator. The study aimed to investigate the importance of chain end functionality on successful emulsion formation, by systematically replacing a fraction of the hydrophobic chain ends with a secondary poly(ethylene glycol) based hydrophilic initiator in a mixed-initiation strategy; a decrease of up to 75 mole percent of hydrophobic chain ends within the branched polymer emulsifiers was shown to maintain comparative emulsion stability. These redundant chain ends allowed for functionality to be incorporated into the polymers via a xanthate based initiator containing a masked thiol group; thiol groups are known to have mucoadhesive character, due to their ability to form disulfide bonds with the cysteine rich areas of mucus. The mucoadhesive nature of emulsions stabilised by thiol-containing branched copolymers was compared to non-functional emulsions in the presence of a biosimilar mucosal substrate and enhanced adherence to the mucosal surface was observed. Importantly, droplet rupture and mucus triggered release of dye-containing oil was seen from previously highly-stable thiol-functional emulsions; this observation was not mirrored by non-functional emulsions where droplet integrity was maintained even in the presence of mucus.
Synthesis and micellization of pH/temperature-responsive double-hydrophilic diblock copolymers polyphosphoester- block -poly[2-(dimethylamino)ethyl methacrylate] prepared via ROP and ATRP
Liu, Xu,Ni, Peihong,He, Jinlin,Zhang, Mingzu
, p. 4771 - 4781 (2010)
Novel pH- and temperature-responsive double-hydrophilic diblock copolymers, poly(ethylethylene phosphate)-block-poly[2-(dimethylamino)ethyl methacrylate] (PEEP-b-PDMAEMA), have been synthesized via the combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). The PEEP block with a bromine-terminated end (PEEP-Br) was first prepared by ROP of 2-ethoxy-2-oxo-1,3,2-dioxaphospholane (EEP) using 2-hydroxyethyl 2-bromoisobutyrate as a bifunctional initiator and stannous octoate as a catalyst. ATRP was then used to polymerize DMAEMA monomer in a methanol/water mixture with PEEP-Br as a macroinitiator, resulting in diblock copolymers of PEEP-b-PDMAEMA. Their chemical structures were respectively characterized by 1H NMR, 13C NMR, 31P NMR, and FT-IR. Their molar mass distributions were determined by gel permeation chromatography (GPC). The critical aggregation concentration (cac) of PEEP-b-PDMAEMA in aqueous solution, which was measured by the fluorescence probe technique, depends on the block composition. The results measured by static laser light scattering (LLS), dynamic light scattering (DLS), and transmission electron microscopy (TEM) reveal that these diblock copolymers are able to self-assemble into aggregates with different particle sizes and morphologies in aqueous solutions, depending on various pH media. On the other hand, the UV-vis measurement shows that these diblock copolymers exhibit a reproducible temperature-responsive behavior with a lower critical solution temperature (LCST) that is tunable by the block composition and pH. In addition, agarose gel retardation assays, TEM, and zeta potential measurements demonstrate that such double-hydrophilic diblock copolymers can effectively condense DNA, potentially useful for the gene delivery.
Hydrogen peroxide responsive polymer nano-carrier with fluorescence ratio characteristic as well as preparation method and application thereof
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Paragraph 0145-0147; 0152-0153, (2020/11/01)
The invention relates to a hydrogen peroxide responsive polymer nano-carrier with a fluorescence ratio characteristic. The nano-carrier is of a spherical micelle structure, and is formed by self-assembling of an amphiphilic block copolymer with hydrogen peroxide responsiveness and ratiometric fluorescence imaging characteristics. The structural formula of the amphiphilic block copolymer having hydrogen peroxide responsiveness and ratiometric fluorescence imaging characteristics is as follows: R1 is a group having hydrogen peroxide responsiveness; R2 is a group with an aggregation-induced emission effect; R3 is a PEG hydrophilic chain; and R5 is a group with strong positive charges. The nano-carrier disclosed by the invention can be used for loading, transporting and program releasing of hydrophobic dye molecules and drug molecules as well as cell imaging and fluorescent molecular probes.
BRANCHED POLYMERS
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Page/Page column 20, (2018/03/06)
The present invention relates to a branched amphiphilic polymer, suitable for stabilizing an emulsion, comprising a plurality of polymer chains comprising hydrophobic chain ends; a plurality of polymer chains comprising functional chain ends capable of associating to a biological substrate; and a plurality of branching units. The present invention also relates to pharmaceutical compositions containing said branched amphiphilic polymers, their methods of use, and methods for their preparation.
