- Bioreducible poly (β-amino esters)/shRNA complex nanoparticles for efficient RNA delivery
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RNA interference (RNAi) mediating gene silencing is a promising approach in the area of gene therapy, but it still is a major challenge to find new non-viral vectors with high transfection efficiency and low toxicity until today. In this work, three novel bioreducible poly (β-amine esters) (PAEs) with different amino monomers in the main chain were designed and synthesized by Michael addition polymerization. All PAEs could condense shRNA into complex nanoparticles with particle size (60-200 nm) and positive surface charges (>+10 mV). The PAEs/shRNA complex nanoparticles (PAENs) were stable under the extracellular physiological condition, while it would degrade in the reductive environment due to the cleavage of the disulfide bonds in the PAEs main chain. PAENs could achieve efficient cellular uptake and EGFP silencing in HEK-293 cells and U-87 MG cells with low cytotoxicity. The high accumulation of PAENs in tumor and high silencing efficiency of intra-tumor EGFP expression occurred when PAENs were intravenously injected into BALB/c mice bearing U-87 MG-GFP tumor. The relationship between the polymer structure and RNAi efficiency and cytotoxicity showed that the density of nitrogen atoms in PAEs backbone and the existence of disulfide bonds demonstrated the remarkable influence on in vitro and in vivo gene silencing efficiency and cytotoxicity. These experimental results suggested that the PAENs could be a promising non-viral vector for efficient RNA delivery.
- Yin, Qi,Gao, Yu,Zhang, Zhiwen,Zhang, Pengcheng,Li, Yaping
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- A new solid acid SO42?/TiO2 catalyst modified with tin to synthesize 1,6-hexanediol diacrylate
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A new solid acid catalyst, SO42?/TiO2 modified with tin, was prepared using a sol-gel method and its physicochemical properties were revealed by nitrogen adsorption-desorption, X-ray powder diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, infrared spectroscopy of adsorbed pyridine, temperature-programmed desorption of ammonia and thermal gravimetric analysis. The structure, acidity and thermal stability of the SO42?/TiO2-SnO2 catalyst were studied. Incorporating tin enlarged the specific surface area and decreased crystallite size of the SO42?/TiO2 catalyst. The total acid sites of the modified catalyst increased and Br?nsted acid strength remarkably increased with increasing tin content. The decomposition temperature of sulfate radical in the modified catalyst was 100 °C greater and its mass loss was more than twice that of the SO42?/TiO2 catalyst. The SO42?/TiO2-SnO2 catalyst was designed to synthesize 1,6-hexanediol diacrylate by esterification of 1,6-hexanediol with crylic acid. The yield of 1,6-hexanediol diacrylate exceeded 87% under the optimal reaction conditions: crylic acid to 1,6-hexanediol molar ratio = 3.5, catalyst loading = 7%, reaction temperature = 130 °C and reaction time = 3 h. The modified catalyst exhibited excellent reusability and after 10 cycles the conversion of 1,6-hexanediol was above 81%.
- Bai, Xiaxia,Pan, Liuyi,Zhao, Peng,Fan, Daidi,Li, Wenhong
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- In situ fabrication of paclitaxel-loaded core-crosslinked micelles via thiol-ene "click" chemistry for reduction-responsive drug release
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In this study, a facile method to fabricate reduction-responsive core-crosslinked micelles via in situ thiol-ene "click" reaction was reported. A series of biodegradable poly(ether-ester)s with multiple pendent mercapto groups were first synthesized by melt polycondensation of diol poly(ethylene glycol), 1,4-butanediol, and mercaptosuccinic acid using scandium trifluoromethanesulfonate [Sc(OTf)3] as the catalyst. Then paclitaxel (PTX)-loaded core-crosslinked (CCL) micelles were successfully prepared by in situ crosslinking hydrophobic polyester blocks in aqueous media via thiol-ene "click" chemistry using 2,2′-dithiodiethanol diacrylate as the crosslinker. These PTX-loaded CCL micelles with disulfide bonds exhibited reduction-responsive behaviors in the presence of dithiothreitol (DTT). The drug release profile of the PTX-loaded CCL micelles revealed that only a small amount of loaded PTX was released slowly in phosphate buffer solution (PBS) without DTT, while quick release was observed in the presence of 10.0 mM DTT. Cell count kit (CCK-8) assays revealed that the reduction-sensitive PTX-loaded CCL micelles showed high antitumor activity toward HeLa cells, which was significantly higher than that of reduction-insensitive counterparts and free PTX. This kind of biodegradable and biocompatible CCL micelles could serve as a bioreducible nanocarrier for the controlled antitumor drug release.
- Huang, Ying,Sun, Rui,Luo, Qiaojie,Wang, Ying,Zhang, Kai,Deng, Xuliang,Zhu, Weipu,Li, Xiaodong,Shen, Zhiquan
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- Preparation method of dihydric alcohol unsaturated carboxylate
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The invention discloses a preparation method of dihydric alcohol unsaturated carboxylate. The method comprises the following steps: 1, adding thionyl chloride to dihydric alcohol in a dropwise manner, carrying out a reaction after dropwise addition is completed, and washing a material obtained after the reaction with water to obtain dihydric alcohol chloride; and 2, adding unsaturated carboxylic acid to the dihydric alcohol chloride obtained in step 1, adding an alkaline substance, adding a polymerization inhibitor, uniformly stirring above materials, heating the obtained mixture to 80-120DEG C, reacting the heated mixture for 1-24h, and centrifuging the obtained reaction product to remove generated chloride and unsaturated carboxylate in order to obtain dihydric alcohol unsaturated carboxylate. The method has the advantages of simple technology, environmental protection, no generation of wastewater, no use of flammable, combustible or carcinogenic organic solvents, no generation of waste gases, and realization of reduction of corrosion to a reaction device and prolongation of the service life of the device due to no use of strong acidic substances in the reactions.
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Paragraph 0022
(2018/02/04)
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- Hydroxy functional acrylate and methacrylate monomers prepared via lipase-catalyzed transacylation reactions
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Candida antarctica lipase B (CAL-B, Novozyme 435) catalyzes the transacylation of methyl acrylate and methyl methacrylate with diols and triols in 2-methyl-2-butanol at 50 °C. Under the experimental conditions, up to 70 mol% of the acyl donor methyl acrylate was converted. Methyl methacrylate is the less efficient acyl donor (up to 60 mol%) due to the higher sterical hindrance in the enzymatic transacylation. Under the reaction conditions high yields of the mono-acylated products are obtained, which contain minor amounts of bis(meth)acrylates. In addition it was observed that Novozyme 435 catalyzes regioselectively the acylation of the primary hydroxyl groups. In comparison with the chemical catalyzed route no selectivity was observed for unsubstituted diols. For substituted diols more mono-acylated product was formed in the lipase-catalyzed reaction than in the chemical catalyzed reaction.
- Popescu, Dragos,Hoogenboom, Richard,Keul, Helmut,Moeller, Martin
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experimental part
p. 80 - 89
(2010/08/20)
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- BIOABSORBABLE ELASTOMERIC POLYMER NETWORKS, CROSS-LINKERS AND METHODS OF USE
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The invention provides elastomeric polymer networks and semi-interpenetrating networks in which a linear PEA, PEUR or PEU polymer is crosslinked by ester or alpha- amino-acid containing cross-linkers that polymerize upon exposure to active species. Bioabsorbable elastomeric internal fixation devices fabricated using such polymer networks and semi-interpenetrating networks are useful for in vivo implant and delivery of a variety of different types of molecules in a time release fashion. Alpha-amino-acid containing ester amide cross-linkers are also provided by the invention.
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Page/Page column 54
(2008/12/04)
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- COMPOSITION FOR POLYELECTROLYTES, POLYELECTROLYTES, ELECTRICAL DOUBLE LAYER CAPACITORS AND NONAQUEOUS ELECTROLYTE SECONDARY CELLS
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A polymer electrolyte-forming composition containing (A) a quaternary ammonium salt of general formula (1) below and (B) an ionic liquid can be converted into a polymer without compromising the excellent properties of the ionic liquid, thus enabling an electrolyte having an excellent safety and electrical conductivity and also a broad potential window to be obtained. In formula (1), R1 to R3 are each independently an alkyl group of 1 to 5 carbons or a substituent having a reactive unsaturated bond and any two from among R1 to R3 may together form a ring, and R4 is methyl, ethyl or a substituent having a reactive unsaturated bond, with the proviso that at least one of R1 to R4 is a substituent having a reactive unsaturated bond. X is a monovalent anion, the letter m is an integer from 1 to 8, and the letter n is an integer from 1 to 4.
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- Liquid oligomers containing acrylate unsaturation
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The liquid oligomeric compositions of this invention are made by the Michael addition reaction of acetoacetate functional donor compounds with multifunctional acrylate receptor compounds where the equivalent ratios of multifunctional acrylate to acetoacetate vary from >/=1:1 to >/=13.2:1 depending on the functionality of both multifunctional acrylate and acetoacetate. Unuseable gelled or solid oligomer products occur below the claimed ranges. The liquid oligomers of this invention are further crosslinked to make coatings, laminates and adhesives.
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