497931-76-7Relevant academic research and scientific papers
Radical polymerization by a supramolecular catalyst: Cyclodextrin with a RAFT reagent
Koyanagi, Kohei,Takashima, Yoshinori,Nakamura, Takashi,Yamaguchi, Hiroyasu,Harada, Akira
, p. 2495 - 2502 (2016)
Supramolecular catalysts have received a great deal of attention because they improve the selectivity and efficiency of reactions. Catalysts with host molecules exhibit specific reaction properties and recognize substrates via host-guest interactions. Here, we examined radical polymerization reactions with a chain transfer agent (CTA) that has α-cyclodextrin (α-CD) as a host molecule (α-CD-CTA). Prior to the polymerization of N,N-dimethylacrylamide (DMA), we investigated the complex formation of α-CD with DMA. Single X-ray analysis demonstrated that α-CD includes DMA inside its cavity. When DMA was polymerized in the presence of α-CD-CTA using 2,2'-azobis[2-(2-imidazolin-2-yl)propane dihydrochloride (VA-044) as an initiator in an aqueous solution, poly(DMA) was obtained in good yield and with narrow molecular weight distribution. In contrast, the polymerization of DMA without α-CD-CTA produced more widely distributed polymers. In the presence of 1,6-hexanediol (C6 diol) which works as a competitive molecule by being included in the α-CD cavity, the reaction yield was lower than that without C6 diol.
Cleavage of polystyrene-b-poly(ethylene oxide) block copolymers with a trithiocarbonate linkage in solutions
Cao, Min,Wang, Jian-Qi,Chen, Peng-Cheng,Xu, Jun-Ting,Fan, Zhi-Qiang
, p. 3834 - 3840 (2010)
In this work, the polystyrene-b-poly(ethylene oxide) (PS-b-PEO) block copolymers with a trithiocarbonate group between the blocks were prepared by polymerization of styrene in the presence of a trithiocarbonate reversible addition fragmentation chain transfer (RAFT) agent connected with PEO. Decomposition of the trithiocarbonate group by UV irradiation was investigated in three different types of solvent: tetrahydrofuran (THF, common solvent for both blocks), cyclohexane/dioxane mixture (selective solvent for the PS block) and N,N-dimethylformamide (DMF)/ethanol mixture (selective solvent for the PEO block). It is found that cleavage of the block copolymers can take place in all these three solvents and the cleavage ratio ranges from 76 to 86%. The micellar morphologies in selective solvents before and after cleavage were examined. It is observed that the size of the micelles is reduced after cleavage and sometimes aggregation of the micelles occurs due to removal of the corona of micelles. It shows that this work provides a facile and general method for synthesis of cleavable block copolymers.
Mixed polymeric micelles as a multifunctional visual thermosensor for the rapid analysis of mixed metal ions with Al3+ and Fe3+
Han, Juan,Cai, Yunfeng,Wang, Yun,Dai, Xiaohui,Wang, Lei,Li, Chunmei,An, Baodong,Ni, Liang
, p. 12853 - 12864 (2018)
A novel type of responsive mixed double hydrophilic block copolymer (DHBC)-based multifunctional visual thermosensor (with mixed copolymers of poly(ethylene oxide)-b-poly(N-isopropylacrylamide-co-2,4-methacryloyl benzaldehyde oxime), (PEG-b-P(NIPAM-co-BDMa)) and poly(ethylene oxide)-b-poly(N-isopropylacrylamide-co-rhodamine 6G methyl acrylic acid) (PEG-b-P(NIPAM-co-Rh6GEMa))), for the detection of Al3+ and Fe3+ was designed and synthesized based on reversible addition-fragmentation chain transfer (RAFT) polymerization. Studies on the sensing processes showed that the multifunctional visual thermosensor has excellent selectivity for Al3+ and Fe3+ ions over many environmentally relevant ions, and high sensitivity with a detection limit on the nanomolar scale. Moreover, the multifunctional visual thermosensor can form micelles with (P(NIPAM-co-BDMa)/P(NIPAM-co-Rh6GEMa)) blocks as the cores and well-solvated PEG blocks as the coronas upon an increase in the temperature, which can enhance the detection sensitivity of Al3+ and Fe3+ ions. The detection limits using 0.05 g L-1 mixed micelles for the analysis of Al3+ and Fe3+ ions decreased from ～5.95 to ～4.02 nM, and ～30.30 nM to ～23.84 nM, respectively, upon changing the temperature from 25 °C to 40 °C. Furthermore, the mixed micelles in combination with Principal Component Analysis (PCA) and linear regression analysis to establish prediction models were used to achieve the successful quantitative detection of the mixed ions with Al3+ and Fe3+.
Design of multi-functional linear polymers that capture and neutralize a toxic peptide: A comparison with cross-linked nanoparticles
Wada, Yusuke,Lee, Haejoo,Hoshino, Yu,Kotani, Shunsuke,Shea, Kenneth J.,Miura, Yoshiko
, p. 1706 - 1711 (2015)
In this paper, a library of multi-functional linear poly-N-isopropylacrylamide (pNIPAm) polymers having a range of molecular weights and functional groups were synthesized and their interaction with the hemolytic peptide, melittin, was examined. The linear pNIPAm (LPs) containing both tert-butyl group and carboxylic acids bound with the peptide by a combination of hydrophobic and electrostatic interactions and neutralized its toxicity. The melittin binding capacity and affinity of each LP was quantified and further compared with cross-linked multi-functional nanogel particles (NPs) having same combination of functional groups. The binding capacity of the LPs (weight of captured melittin/weight of LP) was independent of their molecular weight and was three times higher than that of previously reported NPs. The binding constant depended on the molecular weight of the LPs, showing the highest value of 1.1 × 108 (M-1) for a ～1000 mer linear polymer with 40% tert-butyl group and 20% carboxylic acid. Comparison of the interactions of the LPs and NPs suggested the importance of the flexibility of the polymer chain in order to achieve high binding capacity and affinity. This journal is
Poly(ethylene oxide)-grafted poly(N-isopropylacrylamide) networks: Preparation, characterization and rapid deswelling and reswelling behavior of hydrogels
Zheng, Yaochen,Zheng, Sixun
, p. 176 - 184 (2012)
Poly(ethylene oxide)-grafted poly(N-isopropylacrylamide) networks (PNIPAAm-g-PEO) were prepared via the reversible addition-fragmentation chain transfer polymerization (RAFT) of N-isopropylacrylamide with trithiocarbonate-terminated poly(ethylene oxide) a
In vivo evaluation of folate decorated cross-linked micelles for the delivery of platinum anticancer drugs
Eliezar, Jeaniffer,Scarano, Wei,Boase, Nathan R.B.,Thurecht, Kristofer J.,Stenzel, Martina H.
, p. 515 - 523 (2015)
The biodistribution of micelles with and without folic acid targeting ligands were studied using a block copolymer consisting of acrylic acid (AA) and polyethylene glycol methyl ether acrylate (PEGMEA) blocks. The polymers were prepared using RAFT polymerization in the presence of a folic acid functionalized RAFT agent. Oxoplatin was conjugated onto the acrylic acid block to form amphiphilic polymers which, when diluted in water, formed stable micelles. In order to probe the in vivo stability, a selection of micelles were cross-linked using 1,8-diamino octane. The sizes of the micelles used in this study range between 75 and 200 nm, with both spherical and worm-like conformation. The effects of cross-linking, folate conjugation and different conformation on the biodistribution were studied in female nude mice (BALB/c) following intravenous injection into the tail vein. Using optical imaging to monitor the fluorophore-labeled polymer, the in vivo biodistribution of the micelles was monitored over a 48 h time-course after which the organs were removed and evaluated ex vivo. These experiments showed that both cross-linking and conjugation with folic acid led to increased fluorescence intensities in the organs, especially in the liver and kidneys, while micelles that are not conjugated with folate and not cross-linked are cleared rapidly from the body. Higher accumulation in the spleen, liver, and kidneys was also observed for micelles with worm-like shapes compared to the spherical micelles. While the various factors of cross-linking, micelle shape, and conjugation with folic acid all contribute separately to prolong the circulation time of the micelle, optimization of these parameters for drug delivery devices could potentially overcome adverse effects such as liver and kidney toxicity.
Polymeric micelles using pseudo-amphiphilic block copolymers and their cellular uptake
Benaglia, Massimo,Alberti, Angelo,Spisni, Enzo,Papi, Alessio,Treossi, Emanuele,Palermo, Vincenzo
, p. 2555 - 2562 (2011)
A PS-b-PMA block copolymer bearing a terminal carboxylic group has been synthesized using 3-(benzylsulfanyl thiocarbonylsulfanyl) propionic acid as RAFT agent. When dispersed in methanol, this block copolymer displays pseudo-amphiphilic behaviour providing micelles which can be suspended in water by osmosis. The carboxylic terminations are fundamental during the self-assembling process contributing to the formation of nanosized monodispersed particles. Furthermore, the anionic corona confers the to micelles stability in aqueous media. The core of the micelles was loaded with Nile Red to achieve the intracellular delivery of a lipophilic substance; this was demonstrated by Confocal Laser Scanning Microscopy. The particles, when loaded with doxorubicin, are able to overcome the intrinsic resistance of LoVo-MDR cancer cells. Further stabilization is given to the micelles by covalent shell crosslinking using triethylene glycol diacrylate. Because of the increased intracellular stability of the crosslinked micelles, they stain, when loaded with Nile Red, the aqueous cytosol instead of the lipophilic compartments. The unimers constituting the micelles were covalently labeled with fluorescein to follow their fate once incorporated into the cells.
Minimization of Synthetic Polymer Ligands for Specific Recognition and Neutralization of a Toxic Peptide
Lee, Haejoo,Hoshino, Yu,Wada, Yusuke,Arata, Yuka,Maruyama, Atsushi,Miura, Yoshiko
, p. 10878 - 10881 (2015)
Synthetic polymer ligands (PLs) that recognize and neutralize specific biomacromolecules have attracted attention as stable substitutes for ligands such as antibodies and aptamers. PLs have been reported to strongly interact with target proteins and can be prepared by optimizing the combination and relative proportion of functional groups, by molecular imprinting polymerization, and/or by affinity purification. However, little has been reported about a strategy to prepare PLs capable of specifically recognizing a peptide from a group of targets with similar molecular weight and amino acid composition. In this study, we show that such PLs can be prepared by minimization of molecular weight and density of functional units. The resulting PLs recognize the target toxin exclusively and with 100-fold stronger affinity from a mixture of similar toxins. The target toxin is neutralized as a result. We believe that the minimization approach will become a valuable tool to prepare "plastic aptamers" with strong affinity for specific target peptides.
Novel one pot synthesis of silver nanoparticle-polymer composites by supercritical CO2 polymerisation in the presence of a RAFT agent
Hasell, Tom,Thurecht, Kristofer J.,Jones, Rhys D. W.,Brown, Paul D.,Howdle, Steven M.
, p. 3933 - 3935 (2007)
We report the one pot synthesis of a silver-polymer nanocomposite in supercritical carbon dioxide (scCO2) whereby an organometallic silver complex is thermally decomposed in the presence of a reversible addition fragmentation chain transfer (RAFT) agent during a polymerisation reaction in which the RAFT agent simultaneously stabilises the growing polymer microparticles and the formation of surface located silver nanoparticles. The Royal Society of Chemistry.
Synthesis of a new triple-responsive biocompatible block copolymer: Self-assembled nanoparticles as potent anticancer drug delivery vehicle
Dhara, Dibakar,Dhara, Santanu,Maiti, Saikat,Maity, Pritiprasanna,Poddar, Puja,Sahoo, Satyagopal
supporting information, (2020/07/04)
There has been a continuous effort towards a synthesis of new stimuli-responsive polymer nanoparticle systems for improved cancer chemotherapy over the last decade. In this context, we have presently developed a temperature, pH, and redox-responsive amphiphilic block-copolymer capable of forming nanoparticles in the aqueous medium, targeted towards drug delivery applications. The copper-catalyzed azide-alkyne cycloaddition reaction was utilized to tie the ends of two copolymers - a thermo-responsive poly(N-isopropylacrylamide) based copolymer with an azide end group and a pH-responsive hydrophobic polymer with redox responsive disulfide bond and an alkyne end group, producing a new triple responsive amphiphilic block copolymer (PHNP) that self-assemble in water to produce nanoparticles. Upon heating above the cloud point of poly(N-isopropylacrylamide), these nanoparticles experienced further aggregation to produce larger sized particles as measured by dynamic light scattering, UV–visible spectroscopy, and scanning electron microscopy techniques. PHNP was found to be capable of encapsulating drugs like doxorubicin (DOX) and also fluorescent probes alike Nile Red. The drug release kinetics divulged that in a period of 24 h more than 90percent of the encapsulated DOX was released in pH 5.4 buffer having 10 mM glutathione (GSH) at 40 °C, an environment prevailing in cancer tissues. In vitro studies including live-dead assay and rhodamine-DAPI staining showed that PHNP was non-cytotoxic. DOX-loaded PHNP was observed to be more effective in prohibiting bone cancer cell (MG63) line in comparison to free DOX, demonstrated by the significant reduction of IC50 values. The uptake studies showed that DOX-encapsulated PHNP was more effective for morphometric distortion of MG63 cells in comparison to bare DOX. Therefore, the present research on the development of a biocompatible thermal, pH, and redox-responsive polymer opens up new opportunities in the area of polymeric carrier systems for drug delivery to cancer cells.
