可聚合脂质体的研究 Ⅱ．含桐酸脂质体的稳定性和穿透能力的研究

he stability of mixed liposomes containing β-eleostearic acid (β-ESA>and dimyristoylphosphatidylcholine (DMPC) have been studied by measuring therelease of trapped 5(6)-carboxyfluorescein (5(6)-CF) from the inner phase of liposomes. The results showed that the stability of the mixed liposomes decreased withthe increase of the content of β-ESA in liposomes. Addtion of ethanol and TritonX-100 into the liposome suspensions could damage the liposome structure or induceliposome aggregation, followed by the release ofdye;but less release was observed for the polymerized liposomes when thesame amount of ethanol or Triton X-100 were added, which revealed the increase of stability by polymerization.     

FREE RADICAL RING OPENING POLYMERIZATION OF CYCLIC ACRYLATES

Cyclic acrylates, 2,2- dimethyl-5-methylene-1 , 3-dioxolan-4 -one and 2- phenyl-5-methylene-1,3-dioxolan-4-one, were synthesized successfully. The monomers were characterized by ~1H NMR, ~(13)C NMR, IR and elemental analysis or HRMS. Polymerization of the monomers were carried out at 120℃with di-t-butylperoxide as initiator. The polymers were studied by ~1H NMR, ~(13)C NMR, UV and hydrolysis. The molecular weights of the resulting polymers were estimated by viscosity measurement and the extent of ring opening was estimated also by ~1H NMR and hydrolysis of the polymers and further confirmed by UV spectra.     

Self-assembly of Liposomes Loading Hinesol by Rapid Expansion from Supercritical to Surfactant Solution

<正>To improve the encapsulation efficiency and minimize particle agglomeration of liposomes,rapid expansion from supercritical to surfactant solution(RESSS) was applied to self-assembly of liposomes entrapping hinesol in supercritical carbon dioxide(SC-CO_2) medium.In the process,the solution of liposomal materials and hinesol dissolved in the mixture of SC-CO_2/ethanol was sprayed into a surfactant solution.The surfactant provided stabilization for liposomes by preventing bubbles overflowing and liposomes agglomeration during the spraying process.The encapsulating performance and particle size distribution of liposomes could be controlled by changing expansion processing conditions.When the solution was sprayed into a 5.0%Poloxamer 188 solution at a flow rate of 2 L/min, the entrapment efficiency and average particle size of liposomes were found to be 88.26%and 124 nm,respectively, which came to the standards of Chinese pharmacopoeia.The results show RESSS process provides an innovative method for formation of liposomes incorporating valid compositions extracted from the Chinese traditional medicines in SC-CO_2 medium.     

Design,synthesis and preliminary bio-evaluation of glucose-cholesterol derivatives as ligands for brain targeting liposomes

A series of glucose-cholesterol derivatives 8a-8e as ligands for brain targeting liposomes were synthesized.The preparation of compound 6 involved temporary protection of glucose with chlorotrimethylsilicane and hexamethyldisilazane followed by selectively hydrolyzed.The known cholesteryl tosylate 1 were coupled to ethylene glycols to afford alcohol 2a-2e.Substitution and deprotection of alcohol 2a-2e furnished the acids 4a-4e,which was condensed with compound 6 to get compounds 7a-7e,and then was deprotected in tetrahydrofuran with TFA to obtain the title compounds.As a model drug,tegafur was entrapped by liposomes coupled with 8b,and preliminary in vivo evaluation shown 8b could enhance the ability of liposomes delivering tegafur across the blood brain barrier.     

Lipase-catalyzed synthesis of novel galactosylated cholesterol

In an organic phase system,an enzymes lipase was used as a catalyst to synthesize galactosylated cholesterol,(5-cholesten-3b-yl)[(4-O-β-D-galactopyranosyl)D-glucitol-6]sebacate(CHS-SE-LA),which contains galactose residues.Its chemical structure was characterized by ESI-MS,and NMR.For HepG2 cells,the cellular fluorescence intensities of liposomes modified with CHS-SE-LA(GAL-FL) were as much as 2.6-fold(p 0.01) control liposomes(FL).Moreover,the presence of excess galactose significantly inhibited the uptake of GAL-FL suggesting ASGPR mediated uptake.In conclusion,the novel galactosylated ligand CHS-SE-LA was synthesized by lipase-catalyzation and revealed a great potential as drug carrier materials for hepatocyte-selective targeting.     

Mesoporous CeO2 nanowires as recycled photocatalysts

Mesoporous CeO2 nanowires(NWs) were synthesized through a facile hydrothermal process by using triblock copolymer F127 as the template.XRD analysis confirmed the cubic phase of the synthesized CeO2 NWs.High-yield one-dimensional NWs with accessible mesopores could be observed from SEM and TEM images,and the surface area of the material was confirmed to be 273 m2 g-1 with pore width distribution of 6.9-13.8 nm.The mesoporous CeO2 NWs could be used as efficient photocatalysts for organic dye degradation under UV light irradiation,which was superior compared with commercial photocatalyst P-25 and commercial CeO2 powders.The NW structure facilitates the recovery of catalyst by sedimentation,leading to the impressive reusability of these mesoporous CeO2 NWs.     

Preparation and Characterization of Titania-grafted Poly（styrene-divinybenzene） Nanocomposite Microspheres

Titania-grafted poly（styrene-divinylbenzene）（TiO2/PSt-DVB） nanocomposite microspheres were prepared by an open-ring reaction and radical grafting copolymerization method. The TiO2 nanoparticles were first modified by attachment of epoxy groups to their surfaces to provide reactive groups that could covalently bond to the polymer （PSt-DVB） microspheres. The nanocomposite obtained was characterized by FTIR, SEM, XRD, and TGA analyses as well as UV-Vis spectrophotometry. The results indicated that the TiO2 nanoparticles were uniformly grafted onto the surface of the polymer microsphere producing grain sizes of about 5―10 μm. The modified TiO2 showed better UV absorbing property than the unmodified form, and the nanocomposite also retained the same UV absorbing property as the free modified TiO2 nanoparticle.     

Degradation of Microcystin-RR by Combination of UV/H2O2 Technique

The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the disinfection of water polluted by microcystins. The influence factors such as H2O2, pH and UV light intensities were investigated respectively. Degradation of microcystin-RR （MC-RR） could be fitted by either the pseudo-first-order or second-order rate equations. This homogenous system could significantly enhance the degradation rate due to the synergetic effect between UV and H2O2. The degradation mainly followed the mechanism of direct photolysis and .OH oxidation reactions. Experimental results showed that 94.83% of MC-RR was removed under optimal experimental conditions and the UV/H2O2 system provided an alternative to promote the removal of microcystins in drinking water supplies.     

STUDIES ON DERIVATIVES OF 2,3-DIHYDRO-4H-1,3,2-BENZOXAZAPHOSPHORINE——SYNTHESIS AND STRUCTURE ANALYSIS OF 2,3-DISUBSTITUTED-2,3-DIHYDRO-4H-1,3,2-BENZOXAZAPHOSPHORIN-4-ONE-(THIONE)-2-SULFIDE(OXIDE)

A series of novel organocyclophosphorus compounds including twenty-three 2, 3-disubsti-tuted-2,3-dihydro-4H-1,3,2-benzoxazaphosphorin-4-one-2-sulfide (compounds Ⅰ) and three 2, 3-disubstituted-2,3,-dihydro-4H-1,3,2-benzoxazaphosphorin-4-thione-2-oxide (compounds Ⅱ) havebeen synthesized. Their structures were determined by IR, UV, HNMR, X-ray diffractionand elemental analysis. Each of compounds Ⅰ showed a strong absorption between 1290-1319em~(-1) in the IR spectrum. Comprehensive studies of the spectral data and experimental re-sults indicated that this strong characteristic absorption is different from that of the P = Olinkage and thus could be considered as a result of the stretching vibration of (unsaturatedC)-N single bond. In the course of synthesis of the compounds, an abnormal productisomers could be made predominantly in yield and be readily isolated from the other byrecrystallizing for several times from appropriate solvent. Data for the melting point, IR,UV and HNMR spectra of three pairs o     

Possibility of Targeting Treatment for Ischemic Heart Disease With Liposome (Ⅰ)

This paper reports the basic research on the possibility of using targeting treatment for ischemic heart disease with liposome as drug carrier. Studies have been performed on isolated rat cardiomyocytes, or isolated perfused rat and rabbit hearts. Results show that cardiomyocytes may interact with liposome through fusion, endocytosis, adsorption and molecular exchange of phospholipid. Forms of cellular uptake of liposome depend chiefly on the physicochemical properties of liposomes. Anoxia changes the pattern of liposome uptake by cardiomyocytes and increases uptake of liposomes. Uptake of liposomes, especially of positively charged liposomes by ischemic myocardium is significantly increased. The quantity of increase of liposome uptake is in the following order: ischemia-reperfusion area>peripheral area of the infarct>non-ischemic area>infarcted area. The above results indicate that liposome as drug carrier might promote the delivery of drug into ischemic myocardium and cardiomyocytes.     

MISCIBILITY AND MORPHOLOGY OF THIN FILMS OF BLENDS OF POLYSTYRENE WITH BROMINATED POLYSTYRENES： EFFECTS OF VARYING THE MOLECULAR WEIGHT, BROMINATION DEGREE AND ANNEALING

Thin films of incompatible polymer blends can form a variety of structures during preparation and subsequent annealing process. For the polymer blend system consisting of polystyrene and poIy(styrene-co-p-bromo-styrene), i.e., PS/PBrxS, its compatibility could be adjusted by varying the degree of bromination and the molecular weight of both components comprised, in this paper, surface chemical compositions of the cast and the annealing films were investigated by X-ray photoelectron spectroscopy (XPS) and contact angle measurement; meanwhile, surface topographical changes are followed by atomic force microscopy (AFM). In addition, substantial attention was paid to the effect of annealing on the morphologic variations induced by phase separation and/or dewetting of the thin film. Moreover, the influences of the molecular weight, Aw, as well as the brominated degree, x%, on the sample surface are explored systematically, and the corresponding observations are explained in virtue of the Flory-Huggins theory, along with the dewetting of the polymer thin film.     

Micellization and gelation of the double thermoresponsive ABC-type triblock copolymer synthesized by RAFT

A double thermoresponsive ABC-type triblock copolymer(poly(ethyleneglycol)-block-poly(2-(2-methoxyethoxy) ethyl methacrylate)-block-poly(2-(2-methoxy ethoxy) ethyl methacrylate-co-oligo(ethylene glycol) methyl ether methacrylate, PEG-b-PMEO_2MA-b-P(MEO_2MA-co-OEGMA)) was designed and synthesized by reversible additionfragmentation chain transfer polymerization(RAFT). The ABC-type triblock copolymer endowed a thermal-induced twostep phase transition at 29 and 39 °C, corresponding to the thermosensitive properties of PMEO_2 MA and P(MEO_2MA-coOEGMA) segments, respectively. The two-step self-assembly of copolymer solutions was studied by UV transmittance measurement, dynamic light scattering(DLS), transmission electron microscopy(TEM) and so on. The triblock copolymers showed the distinct thermosensitive behavior with respect to transition temperatures, aggregate type and size, which was correlated to the degree of polymerization of thermosensitive blocks and the molar fraction of OEGMA in the P(MEO_2MAco-OEGMA) segments. In addition, micelles could further aggregate to form the hydrogel by the self-associate of PEG chains under the abduction of the concentration and temperature. The transition from sol to gel was investigated by a test tube inverting method and dynamic rheological measurement.     

Host-Guest Interactions between N,N′-Bis(ferrocenylmethylene)-Diaminobutane and Benzenetetracarboxylic Dianhydride Bridged Bis(β-cyclodextrin)s

A novel water soluble ditopic guest,the quaternary ammonium salt of N,N′-bis(ferrocenylmethylene)-diami-nobutane (1),and a known water soluble ditopic host,benzenetetracarboxylic dianhydride bridged bis(β-cyclo-dextrin)s (2),have been synthesized and characterized.~1H NMR spectra and cyclic voltammogram (CV) studies re-vealed the host-guest interactions between them in aqueous solution.The supramolecular interaction also exists insolid state as confirmed by the studies of the solid samples,which were obtained by frozen-drying the solution sam-ples,using FTIR spectroscopy and differential scanning calorimetry (DSC) techniques.TEM measurement demon-strated that wire-shaped supramolecular aggregates exist in the aqueous solution of the two compounds.The lengthsof the aggregates could reach micrometers.     

Diverse Ring-seco Limonoids from Munronia unifoliolata and Their Biological Activities

Twenty-two new limonoids,mufolinoids A—V(1—22),including six rings A,B-seco limonoids(1—6),twelve ring A-seco limonoids(7—18),four ring-intact limonoids(19—22),together with thirteen known compounds(23—35)were isolated from Munronia unifoliolata.Their structures including absolute configurations were elucidated by combination of NMR,HR-MS,single-crystal X-ray diffraction and calculations of ECD and NMR technologies.Compounds 24,25,33,34 could be significantly reversed the multidrug resistance of MCF-7/doxorubicin(DOX)cells,and the reversal fold(RF)was much higher than that of positive drug Verapamil.Compounds 24,28,and 29 exhibited significant anti-inflammatory activity with the IC50 values in the range of 17.7—39.4μmol/L.Furthermore,compound 29 could markedly inhibit the release of IL-1βby inhibiting the initiation and assembly of NLRP3 inflammasome,which demonstrates the great potential of limonoids as an anti-inflammatory agent.     

Preparation and characterization of star ABC triblock copolymer of ethylene oxide,styrene and methyl methacrylate

A universally significant method,which combines the anionic polymerization with photoinduced charge transfer polymerization,for preparation of soluble star ABC triblock copolymer of ethylene oxide,styrene and methyl methacrylate,was described.The poly(ethylene oxide) (PEO) block was formed by initiation of phenoxy an-ions using p-aminophenol protected by Schiff's base as the parent compound Then the charge transfer system composed of PEO chains with deprotected-amino end groups and benzophenone initiated the polymerization of styrene and methyl metnacrylate sequentially under UV irradiation.The formed star triblock copolymer of styrene,ethylene oxide and methyl methacrylate could be purified by thin-layer chromatography (TLC) and characterized by IR,1H NMR,GPC (gel permeation chromatogrphy) and PGC (pyrolysis gas chromatography).     

Estimating emissions of HCFC-22 and CFC-11 in China by atmospheric observations and inverse modeling

This paper presents the estimation of Chinese emissions of HCFC-22 and CFC-11 in 2009 by an inverse modeling method based on in-situ measurement data from the Shangdianzi Global Atmosphere Watch (GAW) Regional Station (SDZ) and atmospheric transport simulations. After inversion (a-posteriori) estimates of the Chinese emissions in 2009 increased by 6.6% for HCFC-22 from 91.7 (± 83.6) to 98.3 (± 47.4) kt/yr and by 22.5% for CFC-11 from 13 (±12.6) to 15.8 (±7.2) kt/yr compared to an a-priori emission. While the model simulation with a-priori emissions already captured the main features of the observed variability at the measurement site, the model performance (in terms of correlation and mean-square-error) improved using a-posteriori emissions. The inversion reduced the root-mean-square (RMS) error by 4% and 10% for HCFC-22 and CFC-11, respectively.     

铈盐－过硫酸盐复合引发体系的研究

new complex initiation system consists of ceric ion, Ce(IV) and potasiumPersulfate (KPS) for acrylonitrile (AN) aqueous solution polymerization has beenstudied. From Polymerization kinetic studies it showed that the rate ofpolymerization of AN using Ce (IV)/KPS, such as CS(ceric sulfate)/KPS initiation system, is either greater than CS or KPS alone. It hinted that in the complex initiation system the formation of Ce (Ⅲ) via Ce (IV) initiation reactionwould react with KPS to regenerate Ce (IV). This is also revealed by the UV investigation, which showed that at appropriate temperature (above 50℃) Ce (III) could be oxidized by KPS and a new absorption at 330-400 nm was observed by UV spectrometer. Besides, the overall activation energy of polymerization and the effects of concentrations of Ce(IV) and KPS on polymerization were also investigated.     

Fabrication and characterization of gold nano particles for DNA biosensor applications

This research involves the preparation of a biosensor using silicon oxide for biomedical applications, and its effective use for the detection of target DNA hybridization. An electrochemical DNA biosensor was successfully fabricated by using(3-aminopropyl) tri-ethoxysilane(APTES) as a linker molecule combined with gold nanoparticles(GNPs) on a thermally oxidized SiO_2 thin film. The size of the GNPs was calculated by utilizing UV–vis data with an average calculated particle size within the range of 30±5 nm, and characterization by transmission electron microscopy(TEM) and atomic force microscopy(AFM). The GNP-modified SiO_2 thin films were electrically characterized through the measurement of capacitance, permittivity and conductivity using a low-cost dielectric analyzer. The capacitance, permittivity and conductivity profiles of the fabricated sensor clearly differentiated DNA immobilization and hybridization.     

氧化铈纳米粒子光催化降解亚甲基蓝的动力学和机理

 CeO2 nanocrystals were synthesized by a simple precipitation method and calcination at 600 °C. (NH4)2Ce(NO3)6 and ammonia were used as precursors. The CeO2 nanoparticles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and N2 adsorption. The photodegradation of methylene blue catalyzed by CeO2 nanoparticles was studied under UV and sunlight irradiation. The highest degradation was obtained with 1.0 g/L CeO2 at pH 11 within 125 min. The pseudo first order rate constants of dye bleaching were calculated as 16.2x10-3 and 15.7x10-3 min-1 under UV and sunlight irradiation, respectively. The effect of iso-PrOH, iodide ion, and H2O2 was studied to predict the pathway of dye degradation. The obtained results indicate the effect of photogenerated holes in the degradation mechanism of the dye. Also, the photocatalytic activity of the prepared photocatalyst was studied in the presence of several negative ions.     

古紫质AR4重组的磷脂脂质体中的定向自组装

This paper reports, for the first time, that Archaerhodopsin-4 (AR4) could be reconstituted into phospholipid liposomes by self-assembly. AR4 is a new membrane protein isolated from halobacteria H.sp. xz515 in a salt lake of Tibet, China. This is a bacteriorhodopsin (bR) like protein, function as a light-driven proton pump. Experimental measurements verified that similar to bR, AR not only remains its biological activity in pmteoliposome, but also keeps a preferred orientation in self-assembly.