Controlled release of doxorubicin from electrospun MWCNTs/PLGA hybrid nanofibers

In this study, multiwalled carbon nanotubes (MWCNTs) were used to encapsulate a model anticancer drug, doxorubicin (Dox). Then, the drug-loaded MWCNTs (Dox/MWCNTs) with an optimized drug encapsulation percentage were mixed with poly(lactide-co-glycolide) (PLGA) polymer solution for subsequent electrospinning to form drug-loaded composite nanofibrous mats. The structure, morphology, and mechanical properties of the formed electrospun Dox/PLGA, MWCNTs/PLGA, and Dox/MWCNTs/PLGA composite nanofibrous mats were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and tensile testing. In vitro viability assay and SEM morphology observation of mouse fibroblast cells cultured onto the MWCNTs/PLGA fibrous scaffolds demonstrate that the developed MWCNTs/PLGA composite nanofibers are cytocompatible. The incorporation of Dox-loaded MWCNTs within the PLGA nanofibers is able to improve the mechanical durability and maintain the three-dimensional structure of the nanofibrous mats. More importantly, our results indicate that this double-container drug delivery system (both PLGA polymer and MWCNTs are drug carriers) is beneficial to avoid the burst release of the drug and able to release the antitumor drug Dox in a sustained manner for 42 days. The developed composite electrospun nanofibrous drug delivery system may be used as therapeutic scaffold materials for post-operative local chemotherapy.     

用胶束电动毛细管色谱法测定海洋沉积物中苯系物

海洋沉积物中苯系物的分析和测量对海洋石油化探具有重要意义。作者用胶束电动毛细管色谱法对海洋沉积物中苯系物进行了测定。考察了十二烷基硫酸钠 (SDS)的浓度和有机添加剂对分离的影响以及影响峰面积重现性和迁移时间的因素。苯系物的浓度和对应的峰面积成良好的线性关系。将该法用来分析石油勘探远景区域海洋沉积物中的苯系物 ,得到了它们的含量范围。     

N—异丙基丙烯酰胺／丙烯酸十八酯共聚物水溶液胶束及相分？…

合成了Ｎ－异丙基丙烯酰胺（ＮＩＰＡＭ）和丙烯酸十八酯（ＯＤＡ）的共聚物，利用荧光探针和滴重法研究了ＮＩＰＡＭ－烘聚物在水溶液中的胶束形成过程，同时还利用荧光探针法研究了共聚物水溶液在温度升高时出现的ＬＣＳＴ现象，表明该高分子在温度升高时存在着相分离现象，利用Ｌ－Ｂ技术测量共聚物不溶单分子膜的π－Ａ曲线，发现随着温度升高共聚物的单分子膜越来越凝聚的反常现象，这从另一个侧面证实了共聚物ＮＩＰＡＭＯＤＡ     

Folic acid modified electrospun poly(vinyl alcohol)/polyethyleneimine nanofibers for cancer cell capture applications

Capture and detection of metastatic cancer cells are crucial for diagnosis and treatment of malignant neoplasm. Here, we report the use of folic acid (FA) modified electrospun poly(vinyl alcohol) (PVA)/polyethyleneimine (PEI) nanofibers for cancer cell capture applications. Electrospun PVA/PEI nanofibers crosslinked by glutaraldehyde vapor were modified with FA via a poly(ethylene glycol) (PEG) spacer, followed by acetylation of the fiber surface PEI amines. The formed FA-modified nanofibers were well characterized. The morphology of the electrospun PVA/PEI nanofibers is smooth and uniform despite the surface modification. In addition, the FA-modified nanofibers display good hemocompatibility as confirmed by hemolysis assay. Importantly, the developed FA-modified nanofibers are able to specifically capture cancer cells overexpressing FA receptors, which were validated by quantitative cell counting assay and qualitative confocal microscopy analysis. The developed FA-modified PVA/PEI nanofibers may be used for capturing circulating tumor cells for cancer diagnosis applications.     

荧光探针法研究胶原蛋白的水溶液聚集状态

利用一种分子内电荷转移化合物３ 甲氧基 ４’ Ｎ，Ｎ 二甲氨基黄酮（ＤＭＭＦ）作为荧光探针，研究了胶原蛋白在水溶液中的聚集状态．研究结果发现，当胶原蛋白浓度增大到０５ｍｇ／ｍＬ以上时，ＤＭＭＦ在４６５ｎｍ处的荧光强度有一突跃；继续增大其浓度，荧光强度越来越大．证明胶原蛋白在水溶液中随浓度增大有明显的聚集行为．利用荧光偏振法测量该体系内ＤＭＭＦ的荧光偏振特性，发现当胶原蛋白浓度增大到０５ｍｇ／ｍＬ以上时，体系具有较高的微粘度，进一步证实了胶原蛋白在水溶液中的聚集特性．     

Formation of multifunctional Fe_3O_4/Au composite nanoparticles for dual-mode MR/CT imaging applications

Recent advances with iron oxide/gold(Fe3O4/Au) composite nanoparticles(CNPs) in dual-modality magnetic resonance(MR) and computed tomography(CT) imaging applications are reviewed. The synthesis and assembly of "dumbbelllike" and "core/shell" Fe3O4/Au CNPs is introduced. Potential applications of some developed Fe3O4/Au CNPs as contrast agents for dual-mode MR/CT imaging applications are described in detail.     

树状大分子包裹金纳米颗粒的制备、尺寸控制和稳定性研究

作者以氨基封端的第五代聚酰胺胺(PAMAM)树状大分子为模板,借助静电相互作用将氯金酸盐吸引进入树状大分子内部,再由外加还原剂硼氢化钠将金盐原位还原,得到了树状大分子包裹的金纳米颗粒(Dendrimer-Entrapped Gold Nanoparticles,Au DENPs),并应用紫外、表面电势法、透射电镜和能量色散谱等手段对其结构进行表征。通过改变氯金酸与树状大分子的投料比,平均尺寸在1.9~2.8nm的Au DENPs被成功制备。制得的Au DENPs不仅在水、PBS缓冲液以及生理环境下稳定存在,还在较宽的pH(pH=5~8)与温度(4~50℃)范围内稳定,为其应用于生物医学领域提供了可能。     

基于树状大分子的纳米CT成像造影剂的制备及其生物医学应用

树状大分子是一类高度支化的单分散性大分子,具有精确可控的分子结构.本文在树状大分子结构特点的基础上,阐述了以树状大分子为载体的新型纳米CT成像造影剂的合成及其在CT成像中的应用,并对树状大分子在CT成像中的发展趋势和应用领域进行了展望.     

胶束电动毛细管色谱法测定海洋沉积物中的苯、甲苯和二甲苯

 建立了用胶束电动毛细管色谱法（MECC）对海洋沉积物中的苯、甲苯和二甲苯进行 分析测定的方法 。用45 cm（到检测窗口40 cm）×75　μm i.d.毛细管柱,以75　mmol/L SDS-2　mmol/L 四硼酸钠溶液（外加体积分数为20%的甲醇）为缓冲液（pH 9.16）。当电压为25 kV、检测 波长为200 nm时,苯、甲苯和二甲苯在20 min内得到了良好的分离。用峰面积定量,线性范 围为4～50 mg/L,相对标准偏差在6.2%以内。测得海洋沉积物中的这些苯系物的质量比范围 为3.79～17.36 μg/g。     

荧光探针法对N-异丙基丙烯酰胺-丙烯酰胺共聚物水溶液相变的研究

合成了多种不同配比的N 异丙基丙烯酰胺 (NIPAM )与丙烯酰胺 (AM )的共聚物 .用荧光探针法研究了共聚物溶液荧光光谱随温度升高而引起的变化 .研究表明 :共聚物的最低临界溶液温度 (LCST)取决于AM与NIPAM的组成比 .AM的比例越大 .LCST就越高 ,且有较好的正比关系 .通过以共价键连接于共聚物的荧光探针法 (标记法 )和以小分子探针混入共聚物水溶液的方法 (混入法 )测定上述体系LCST的结果比较 ,发现标记探针法具有较高的灵敏度 ,更适宜用来研究共聚物水相体系的相变问题 .