PLGA包裹的紫杉醇缓释微球的理化性质及抑瘤活性研究

用化学材料聚乳酸和乙醇酸的共聚物(poly(lactic—co-glycolicacid),PLGA)制备了紫杉醇缓释微球。用扫描电镜观察了微球的形态和大小,用HPLC法测定了紫杉醇在介质中的释放情况,用MIT法测定了IC50,通过荷瘤裸鼠实验评价了体内抑瘤活性。结果表明,PLGA-紫杉醇微球呈光滑球形,平均粒径7～37μm,微球包封率在90％以上。PLGA-紫杉醇微球具有缓释作用,其抑瘤活性与紫杉醇从微球内的释放密切相关,微球可以维持较长时间的有效药物浓度,达到了更好的抑瘤效果。     

基于高速摄影的自反应淬熄团聚粉飞行燃烧行为研究

含铁氧体成分的空心复相陶瓷微珠是一种新型轻质吸波材料。本文以Al-TiO2-Fe-Fe2O3-MnO2-蔗糖-环氧树脂为反应体系,经球磨、烘干、碳化、粉碎、筛分制成粒径为50-90μ的团聚粉,利用自反应淬熄技术熔射团聚粉获得了含铁氧体成分的空心复相陶瓷微珠。用SEM表征了淬熄前后团聚粉的形貌变化,通过高速摄影技术研究分析了团聚粉粒子在熔射过程中的飞行燃烧行为。试验结果表明,团聚粉粒子在飞行燃烧过程中经历受热蓄能、热释放与后燃烧三个阶段形成空心陶瓷熔滴,该熔滴在大过冷条件下凝固结晶最终形成空心陶瓷微珠。     

Preparation and characterization of hollow α-Fe2O3 irregular microspheres

Hollow α-Fe₂O₃ irregular microspheres were prepared at 160 °C from a hydrolyzing Fe(ClO₄)₃ solution by adding sodium polyanethol sulphonate. The particles were characterized by ⁵⁷Fe Mössbauer, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The walls of these hollow particles consisted of elongated subunits composed of elongated and thin α-Fe₂O₃ rods. The precipitation of hollow α-Fe₂O₃ irregular microspheres was governed by the preferential adsorption of sulphonate/sulphate groups. The lateral aggregation of elongated thin rods and subunits also played an important role in the formation of hollow α-Fe₂O₃ irregular microspheres.     

Fabrication and characterization of chitosan microspheres agglomerated scaffolds for bone tissue engineering

In the presented paper authors describe a method for bone scaffolds fabrication. The technique is based on the agglomeration of chitosan microspheres. The fabrication process is complex and consists of a few steps: chitosan spheres extrusion, scaffold formation by compression followed by the spheres agglomeration and bonding with cross-linking agent (STPP, sodium tripolyphosphate). The described method allows manufacturing of porous materials with controllable shape, pore size distribution and their interconnectivity. In this technique 3D scaffold porosity can be regulated by altering spheres diameter. Authors studied influence of cross-linker concentrations and time of cross-linking process on the scaffold morphology, mechanical properties, enzymatic degradation rate (in the presence of lysozyme) and human osteoblasts response. Surface morphology and topography were evaluated by SEM. Porosity and pore interconnectivity were observed via μCT scanning. Mechanical tests showed that chitosan scaffolds perform compression characteristic (Young Modulus) similar to natural bone. Cytotoxicity established by XTT assay confirmed that most of the developed composite materials do not show toxic properties. Osteoblast adhesion and morphology were analyzed by SEM and optical microscopy.     

Novel PEO-based composite solid polymer electrolytes incorporated with active inorganic–organic hybrid polyphosphazene microspheres

Inorganic–organic hybrid poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) microspheres with active hydroxyl groups were incorporated in poly(ethylene oxide) (PEO), using LiClO₄ as a dopant salt, to form a novel composite polymer electrolyte (CPE). The polymer chain flexibility and crystallinity properties are studied by DSC. The effects of active PZS microspheres on the electrochemical properties of the PEO-based electrolytes, such as ionic conductivity, lithium ion transference number, and electrochemical stability window are studied by electrochemical impedance spectroscopy and steady-state current method. Maximum ionic conductivity values of 3.36 × 10⁻⁵ S cm⁻¹ at ambient temperature and 1.35 × 10⁻³ S cm⁻¹ at 80 °C with 10 wt.% content of active PZS microspheres were obtained and the lithium ion transference number was 0.34. The experiment results showed that the inorganic–organic hybrid polyphosphazene microspheres with active hydroxyl groups can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolytes more effectively comparing with traditional ceramic fillers such as SiO₂.     

磁性微球表面光引发聚合制备金属配位印迹层及选择性富集奶样中氟喹诺酮类药物残留

目的发展一种金属配位印迹磁性微球的制备方法,并用于奶样中氟喹诺酮类药物残留的选择性富集。方法采用简便的溶剂热法合成磁性纳米粒子,再采用溶胶-凝胶法制备磁性硅胶微球,然后在磁性硅胶微球表面接枝光引发剂,在125 W紫外灯辐射下合成恩诺沙星-Co(Ⅱ)配位印迹层,并用于磁分散萃取奶样中恩诺沙星、环丙沙星和洛美沙星。结果该方法的加标回收率为89.6%~100.8%,相对标准偏差为1.4%~5.5%,其中环丙沙星的检出限和定量限分别为1.72μg/kg和5.74μg/kg,洛美沙星的检出限和定量限分别为2.05μg/kg和6.82μg/kg,恩诺沙星的检出限和定量限分别为1.18μg/kg和3.94μg/kg。结论该样品处理方法是一种选择性好、简单快速的分离检测奶样中氟喹诺酮类药物残留的方法。     

聚烯丙基氯化铵调控下多孔羟基磷灰石微球的合成及作为药物载体的应用研究

选用聚烯丙基氯化铵(PAH)作为晶体生长调节剂, 在水热条件下成功制备了多孔羟基磷灰石(Hydroxyapatite, HAP)中空微球。详细研究了反应时间和添加剂浓度等因素的影响: 150℃水热反应12 h, 控制PAH 浓度0.3~0.5 g/L, 可合成尺寸均匀、孔径密集的HAP中空微球。微球生长经历早期前驱体微结构、异相成核、相转化等不同阶段, 聚合物在各阶段都起到重要的调节作用。以典型的布洛芬(ibuprofen, IBU)作为模型药物, 研究微球的药物负载和脱附能力。结果显示: 多孔微球具有良好的药物负载和释放能力, 吸附量较好, 可达到413.65 mg/g。且药物具有较好的pH响应释放行为, 可作为pH敏感靶向药物载体应用到生物医学等领域。     

铝合金基底微碳球作为润滑油添加剂的摩擦学性能及其润滑机理

采用绿色水热制备方法, 以葡萄糖为前身化合物一步制得直径在400~500 nm、尺寸均匀的单分散微碳球, 采用扫描电子显微镜、红外光谱等手段对微碳球的表面形貌及化学特性进行表征, 利用多功能摩擦磨损试验机考察了微碳球作为润滑油添加剂在铝合金-钢摩擦副的减摩耐磨特性, 探讨了微碳球的润滑作用机理。结果表明: 将微碳球作为液体石蜡和商用机油润滑添加剂可以显著提高铝合金-钢摩擦副上的摩擦学性能, 这主要是因为在滑动过程中微碳球可能进入到接触区, 阻止摩擦副之间的直接接触, 并起到纳米滚珠作用。     

低密度Fe3O4/中孔炭微球复合材料的可规模制备及吸波性能

采用喷雾干燥法制备出中孔炭微球(MCMSs), 进一步通过液相浸渍得到磁性Fe₃O₄/MCMSs纳米复合材料, 系统研究了复合材料的形貌结构和吸波性能。结果发现, Fe₃O₄/MCMSs复合材料具有优异的流动性和低密度(0.24~0.33 g/cm³)特征, 其中Fe₃O₄纳米颗粒高度分散在MCMSs中孔孔道内。复合材料具有较高的比表面积(548~735 m²/g), 可以促进多种介电弛豫的形成。在2~18 GHz范围内, 复合材料以介电损耗为主, 在12.6 GHz处具有最大反射率-25 dB, 小于-10 dB的带宽达4.7 GHz。复合材料优异的吸波性能可以归因于均相分布的Fe₃O₄纳米颗粒和中孔炭微球的协同作用, 在增大界面弛豫和电磁波散射的同时, 改善了阻抗匹配, 减少了电磁波在吸波层表面的反射。     

石墨烯量子点/CdS/CdSe共敏化太阳能电池

以三维锐钛矿TiO₂微球为上层光散射层材料, 以商业纳米TiO₂为下层连接材料, 采用刮刀法制备了一种新颖的双层TiO₂薄膜, 并应用于量子点敏化太阳能电池(QDSSC)。其中, 石墨烯量子点(GQDs)采用滴液法引入, CdS/CdSe量子点采用连续离子层吸附法(SILAR)制备。采用场发射扫描电镜、透射电镜、X射线衍射、紫外-可见漫反射光谱及荧光光谱对样品进行表征。实验还制备了CdS/CdSe量子点敏化及石墨烯量子点/CdS/CdSe共敏化太阳能电池, 并研究了石墨烯量子点及CdS不同敏化周期及对电池性能影响。研究结果表明, 石墨烯量子点及CdS不同敏化周期对薄膜的光学性质、电子传输及载流子复合均有较大影响。优选条件下, TiO₂/QGDs/CdS(4)/CdSe电池的光电转换效率为1.24%, 光电流密度为9.47 mA/cm², 显著高于TiO₂/CdS(4)/CdSe电池的这些参数(0.59%与6.22 mA/cm²)。这主要是由于TiO₂表层吸附石墨烯量子点后增强了电子的传输, 减少了载流子的复合。