Institute of Chemistry
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A pH sensitive co-delivery system of siRNA and doxorubicin for pulmonary administration to B16F10 metastatic lung cancer
No full textPulmonary co-delivery to the lungs offers a potential therapy for pulmonary diseases. In this study, doxorubicin was conjugated to polyethyleneimine by hydrazone bonds to form a pH sensitive conjugate (PEI-HZ-DOX). A co-delivery carrier was constructed by complexing Bcl2 siRNA with PEI-HZ-DOX. The complex particles could be used by pulmonary administration for metastatic lung cancer treatment. DOX release from the PEI-HZ-DOX conjugate was in a pH-dependent pattern and accelerated by decreasing pH. The cell uptake of DOX and siRNA from PEI-HZ-DOX/siRNA and efficient intracellular release of DOX from PEI-HZ-DOX in B16F10 cells were further confirmed. Cell apoptosis and antitumor effects of the combined therapy were evaluated in vitro, the results showed that co-delivery of DOX and siRNA had better antitumor efficacy than mono-delivery of DOX or siRNA. Furthermore, the biodistribution results showed that pulmonary administration could improve the deposition amounts of DOX and siRNA in the lungs and prolong the retention time compared with systemic administration, which demonstrated that the present delivery system is suitable for pulmonary co-delivery. Overall, pH sensitive PEI-HZ-DOX/siRNA complex nanoparticles exhibit great potential for clinical combination therapy of lung cancer by pulmonary administration in local delivery strategies
Crystallization behavior of PEG/PLLA block copolymers: Effect of the different architectures and molecular weights
Get PDFPEG/PLLA block copolymers bearing various number of arms were synthesized. The molecular weights of PLLA in the block polymers were determined by H-1 NMR and GPC. For 1-arm, 2-arm, 4-arm PEG/PLEA block copolymers, DSC and WAXD results indicated that the different architectures and compositions of the block copolymers didn't alter the structures of PEG and PLEA crystallites, but markedly affected the crystallinities and melting temperatures of PEG and PLEA. The critical M-n,M-pLLA of each arm decreased with the number of arms increasing (M-n,(MPEG5-PLIA) > M-n,(2PEG10-PLLA) > M-n,(4PEG20-PLLA)), when the PEG crystallites were not detected. As M-n (PLLA) of each arm was similar in the copolymers, T-m, (PEG) and X-PEG decreased gradually with the number of arms increasing, and the similar regularities also displayed for PLLA. The crystallization behavior and the variation architectures of PEG/PLEA copolymers can provide primary data to the applications in the drug delivery and industry parts. (C) 2015 Elsevier Ltd. All rights reserved
Magnetic coupled passive direct methanol fuel cell: Promoted CO2 removal and enhanced catalyst utilization
No full textA novel approach was proposed to promote CO2 removal from the anode catalyst layer of a liquid-fed passive direct methanol fuel cell (DMFC) by introducing Lorentz force via magnetic field integrating. Due to the promoted removal of CO2 micro-bubble, the physical block of triple-phase boundary in the anode catalyst layer was reduced evidently. CO2 removal was promoted through introducing forced convection around the CO2 bubbles which can be proved by the mathematical calculations. Performance of the vapor-fed DMFC, in where no CO2 bubble existing in the anode, did not change by the magnetic field, also indicated that the enhanced performance of the liquid-fed magnetic-coupled DMFC was resulted from the promotional CO2 removal. A 12.5% enhancement in maximum power density was obtained for the liquid-fed DMFC by combining the magnetic field. (C) 2014 Elsevier Ltd. All rights reserved
环境友好溶液法制备高效率 Cu2ZnSn(S,Se)4太阳能电池
No full text锌黄锡矿结构的Cu2ZnSn(S,Se)4具有优异的光学性能，组成元素都是地壳的丰产元素，且安全无毒，特别适合未来制备高效、廉价的薄膜太阳能电池。国内外科研人员采用多种方法制备高质量的Cu2ZnSn(S,Se)4吸光层材料，主要包括真空法和溶液法。其中利用溶液的方法备受青睐，因为该方法生产设备成本低廉，不需要昂贵的真空制膜设备；采用印刷技术可以连续快速成膜，速度快、投资少、效率高；另外通过改变溶液的组分可以来控制预制膜的组成。因此，溶液法更适合将来薄膜太阳能电池大规模生产。近来，美国IBM公司沃森研究中心采用肼作为溶剂的方法制备Cu2ZnSn(S,Se)4太阳能电池，获得了12.6%的光电转化效率，这更加坚定了人们对该材料产业化的信心。然而，肼是一种高毒、高致癌、易爆炸的危险品试剂，势必会对将来的大规模生产薄膜太阳电池带来不利影响。基于以上原因，本论文的研究重点在于寻找绿色环保、廉价的溶剂...Cu2ZnSn(S,Se)4 has gained much attention as a promising absorber material for next generation thin film solar cells due to its low material cost and its high photoelectric conversion efficiency. Numerous deposition approaches have been reported to fabricate high quality Cu2ZnSn(S,Se)4 absorber layers including vacuum and non-vacuum processes. Solution-deposited approaches play an important role in reducing the manufacturing cost of Cu2ZnSn(S,Se)4 thin film solar cells. Recently, Mitzi et al. developed a hydrazine-based solution approach to fabricate Cu2ZnSn(S,Se)4 solar cells with a photoelectric conversion efficiency beyond 12%. Although it is a very promising approach only in terms of efficiency, hydrazine is an extremely toxic and highly explosive solvent. The research interest of this ..
蛇莓抑制NA的活性成分鉴定及不同NA抑制剂协同作用
No full text流行性感冒又称流感，是由流感病毒引起的急性呼吸道感染，传染性强，传播速度快。根据世界卫生组织《急性呼吸道感染病报告》（2009年2月更新）统计，全球每年流感大流行期间流感病例约为10亿，重症病例为300万例，并有25万至50万人因此死亡。流感的危害非常严重，而流感病毒则是这一危害的罪魁祸首。 目前疗效最好的抗流感药物是神经氨酸酶抑制剂奥司他韦（oseltamivir）和扎那米韦（zanamivir），但流感病毒惊人的突变能力造成耐药病毒株的出现以及药物本身的副作用，使得扎那米韦和奥司他韦的应用遭到限制。因此，要有效遏制流感，新的抗流感病毒药物的研发和使用迫在眉睫。神经氨酸酶（NA）是存在于A型和B型流感病毒表面的一种糖蛋白，它在子代病毒释放和扩散中有着至关重要的作用，主要表现：①促进新生病毒从感染的细胞中释出；②阻止子代病毒从宿主细胞中释出后的聚集。在所有A型和B型流感病毒的NA都有一致性，即：其活性空腔均位于亚单位表面的口袋中，且催化位点的氨基酸残基均高度保守，因而可作为抗流感病毒药物的靶点。 我国有着丰富的中草药资源，在几千年的发展历史中，中草药在预防抵抗感冒方面功不可没。在对400多种传统中药的提取物进行以甲型流感病毒神经氨酸酶为靶点的系统筛选时，筛选出了五种对流感病毒神经氨酸酶抑制作用显著的中药：蛇莓、路路通、苦楝皮、夏枯草、紫草。我们选取了蛇莓为研究对象，对其具有神经氨酸酶抑制作用的物质基础进行了研究。 将蛇莓全草粉碎，利用工业酒精冷浸提取得到蛇莓提取物的总的粗浸膏。依次用石油醚、乙酸乙酯、正丁醇进行萃取，得到极性不同的石油醚部位、乙酸乙酯部位、正丁醇部位和水部位的提取物。总提取物和各分提取物对流感病毒神经 氨酸酶抑制作用的药理活性筛选结果表明，乙酸乙酯部位对神经氨酸酶的抑制作用最强。对该部位进行分离，最终得到五个有活性的单体化合物。并以槲皮素为阳性对照药，对这五种单体化合物进行了对甲型流感病毒神经氨酸酶体外抑制作用的评价。 抗流感药物的疗效在一定范围内与使用剂量成正比，但随着用药剂量的增加，因为用药而发生的毒副作用的风险也会相应的随之增加。作为抗流感药物的神经氨酸酶抑制剂亦不例外。寻找并发现有协同作用的抗流感药物可以使抗流感药物在治疗安全范围内有着更好的疗效：减少流感病毒株出现耐药性的可能性；降低用药剂量，减少因使用抗流感药物而产生的毒性。为此，本次论文选取了木犀草素等十几种不同的神经氨酸酶抑制剂，将其分别与蛇莓中分离鉴定出的对神经氨酸酶有抑制作用的活性成分混合，采用荧光测定法测试其体外对神经氨酸酶的抑制作用。实验结果表明木犀草素、黄芩素分别与委陵菜酸等蛇莓的活性成分混合后的体外抗流感作用增强，有望开发出新的抗流感药物配方。Influenza is caused by influenza virus. It’s acute respiratory tract infection, possessing strong infectivity and traveling fast. According to the World Health Organization, each year there is about 1 billion of pandemic flu cases, including 3 millions of severe cases and 250000 to 500000 people died as a result. The harm of flu is very serious and the flu virus is the culprit. At the present, the best anti-flu drugs are neuraminidase inhibitors, like oseltamivir and zanamivir. However the emergence of resistant strains caused by the influenza virus’s phenomenal ability of mutation and the side effects of the drug itself make the applications of oseltamivir and zanamivir limited. To effectively curb the flu, development for a new anti-influenza virus drug is imminent. Neuraminidase (NA) exists in type A and type B influenza virus. NA is one kind of glycoprotein on the surface of influenza virus. NA plays a vital role in the progeny virus release and diffusion, mainly in two sides: ①to promote the new virus released from infected cells ②to prevent the progeny virus from gathering when released from the host cell. All NA of type A and type B influenza virus have one consistency, namely: the active pockets are located on the surface of the cavity in the unit, and amino acid residues on the catalytic site are highly conserved, which can be used as anti flu drug targets. Our country has a rich resource of Chinese herbal medicine and during the several-thousand-year development history. Chinese herbal medicines are important in the aspect of prevention against cold. When screening on more than 400 kinds of traditional Chinese medicine extract by influenza virus neuraminidase targets system, we found that five kinds of traditional Chinese medicine (TCM) had significant neuraminidase inhibitory effect: Duchesnea indica (Andr.) Focke, Fructus Lipuidambaris Liquidambar taiwaniana Hance, Lithospermum erythrorhizon Sieb. et Zucc., Melia toosendan Sieb. et Zucc., Prunlla vulgaris L. We chose the Duchesnea indica (Andr.) Focke as the research object to study the active substance. Duchesnea indica (Andr.) Focke was shattered into pieces and extracted by industrial alcohol. Then the crude extract was extracted with petroleum ether, ethyl acetate and n-butanol in turn and we got different polar parts: petroleum ether, ethyl acetate parts, n-butanol and water area. The crude extract and the extracted parts were tested in vitro to know their influenza virus neuraminidase inhibitory effects. Screening results showed that ethyl acetate part had the strongest neuraminidase inhibitory effect. We separated this part and finally found five active monomer compounds. In the research, we evaluated the anti-NA effect of the five compounds in vitro with quercetin as the positive control drug. The curative effect of anti-influenza drugs within a certain range is proportional to the dosage. However, with the increase of dosage, the risk of the side effects of drugs will be increased accordingly. It’s the same for NA inhibitors as a kind of anti-flu drugs. To find concurrent existing synergy anti-flu drugs can make anti-flu drugs have a better curative effect in the safety range: reducing the appearence of drug-resistant flu strains, reducing the dosage of anti-flu drugs and reducing the toxicity due to use of anti-flu drugs. As a result, we selected dozens of NA inhibitors including Luteolin and texted the anti-NA effect by way of Fluorimetry when used with the active anti-NA ingredients of Duchesnea indica (Andr.) Focke. The experimental results showed that the anti-NA effects of Luteolin and Baicalein were increased when used respectively with the active anti-NA ingredients of Duchesnea indica (Andr.) Focke in vitro, which may resulted in a new anti-flu drug formulations
Host-Sensitized Luminescence Properties in CaNb2O6In3+ (Ln(3+) = Eu3+/Tb3+/Dy3+/Sm3+) Phosphors with Abundant Colors
No full textA series of Ln(3+) (Ln(3+) = Eu3+/Tb3+/Dy3+/Sm3+) ion doped CaNb2O6 (CNO) phosphors have been prepared via the conventional high-temperature solid-state reaction route. The X-ray diffraction (XRD) and structure refinement, diffuse reflection, photoluminescence (PL), and fluorescent decay curves were used to characterize the as-prepared samples. Under UV radiation, the CNO host present a broad emission band from about 355 to 605 nm centered around 460 nm originating from the NbO6 octahedral groups, which has spectral overlaps with the excitation of f-f transitions of Eu3+/Tb3+/Dy3+/Sm3+ in CNO:Eu3+/Tb3+/Dy3+/Sm3+ samples. They show both host emission and respective emission lines derived from the characteristic f-f transitions of activators, which present different emission colors owing to the energy transfer from the NbO6 group in the host to Eu3+/Tb3+/Dy3+/Sm3+ with increasing activator concentrations. The decreases of decay lifetimes of host emissions in CNO:Eu3+/Tb3+/Dy3+/Sm3+ demonstrate the energy transfer from the hosts to Eu3+/Tb3+/Dy3+/Sm3+. The energy transfer mechanisms in CNO:Eu3+/Tb3+/Dy3+ phosphors have been determined to be a resonant type via dipole-dipole mechanisms. For CNO:Sm3+, the metal-metal charge transfer transition (MMCT) might contribute to the different variations of decay lifetimes and emission intensity from CNO:Eu3+/Tb3+/Dy3+ samples. The best quantum efficiency is 71.2% for CNO:0.01/0.02Dy(3+). The PL properties of as-prepared materials indicate the promising application in UV-pumped white-emitting lighting diodes field
Hemocompatible, antioxidative and antibacterial polypropylene prepared by attaching silver nanoparticles capped with TPGS
No full textInfections associated with medical devices cause significant costs, morbidity, and mortality. Medical devices with hemocompatibility, antioxidative stress, and antibacterial properties are difficult to fabricate. In this study, silver nanoparticles (Ag NPs) were synthesized for the first time in the presence of carboxylic D-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) as antibacterial agents. The Ag NPs were characterized by UV-visible spectroscopy, transmission electron microscopy, and zeta potential measurements. The results showed that Ag NPs had a good dispersion stability and uniform size distribution. The introduction of TPGS dispersed the Ag NPs in solution and provided active protection against Ag NP-induced free radical damage. N-Isopropylacrylamide (NIPAAm) and N-(3-aminopropyl) methacrylamide hydrochloride (APMA) were then co-grafted onto polypropylene (PP) membranes by ultraviolet grafting, which can provide antifouling properties. The modified PP surface can be used as a platform to load the Ag NPs capped with TPGS. The loading efficiency of Ag NPs was mediated by electrostatic interactions between the positively charged APMA and the negatively charged Ag NPs. The loaded TPGS can slow the lipid peroxidation of erythrocytes and fill the lipid bilayer of erythrocytes to prevent antioxidative stress and hemolysis. The bacteria adhesion, bacterial activity, and biofilm formation proved that the modified PP surfaces loaded with Ag NPs had excellent antibacterial and bactericidal properties. Therefore, our approach can serve as a basis for developing medical devices with excellent hemocompatibility, as well as simultaneous antioxidative and antibacterial properties, thereby providing a potential prevention measure of medical-device-associated infections
Enzyme-regulated the changes of pH values for assembling a colorimetric and multistage interconnection logic network with multiple readouts
No full textBased on enzymatic reactions-triggered changes of pH values and biocomputing, a novel and multistage interconnection biological network with multiple easy-detectable signal outputs has been developed. Compared with traditional chemical computing, the enzyme-based biological system could overcome the interference between reactions or the incompatibility of individual computing gates and offer a unique opportunity to assemble multicomponent/multifunctional logic circuitries. Our system included four enzyme inputs: beta-galactosidase (beta-gal), glucose oxidase (GOx), esterase (Est) and urease (Ur). With the assistance of two signal transducers (gold nanoparticles and acid-base indicators) or pH meter, the outputs of the biological network could be conveniently read by the naked eyes. In contrast to current methods, the approach present here could realize cost-effective, label-free and colorimetric logic operations without complicated instrument. By designing a series of Boolean logic operations, we could logically make judgment of the compositions of the samples on the basis of visual output signals. Our work offered a promising paradigm for future biological computing technology and might be highly useful in future intelligent diagnostics, prodrug activation, smart drug delivery, process control, and electronic applications. (C) 2015 Elsevier B.V. All rights reserved
An investigation of spinel NiCo2O4 as anode for Na-ion capacitors (vol 114, pg 726, 2013)
No full textTemplated Self-Assembly of Block Copolymers and Morphology Transformation Driven by the Rayleigh Instability
No full textIn the current study, we investigate the self-assembly of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) confined in the nanopores of the anodic aluminum oxide (AAO) template and the subsequent morphology transformation induced by the Rayleigh instability. PS-b-P4VP nanotubes and nanorods with various internal nanostructures are fabricated by wetting the AAO template with PS-b-P4VP/chloroform solution, and then followed by solvent evaporation. After the removal of AAO template by potassium hydroxide solution, several different solvents (chloroform, toluene, and N,N-dimethylformamide) with different qualities are used to swell and anneal those nanotubes and nanorods suspended in aqueous media. Morphology transformation from nanostructured PS-b-P4VP nanotubes or nanorods to ordered nanospheres is observed by annealing upon chloroform and toluene while the morphology remains unchanged upon N,N-dimethylformamide annealing, indicating that solvent quality is a key factor in tuning the morphology and internal structures. Kinetics study and theoretical analysis for the morphology transition from two-dimensional (2D) block copolymer (BCP) nanotubes and nanorods to three-dimensional (3D) BCP nanospheres are further performed. From the morphological evolution and the quantitative calculation, it is confirmed that this transition is induced by the Rayleigh instability. This study provides a simple but promising method, that is, solvent annealing method, for the fabrication of BCP nanospheres with ordered internal nanostructures, which may have great application in drug delivery and other nanotechnology