硫酸软骨素酶ABC和环磷酸腺苷缓释组织工程 支架的构建

目的:制备一种可生物降解有效安全的硫酸软骨素酶ABC(ChABC)和环磷酸腺苷(cAMP)缓释组织工程支架,使药物缓慢稳定释放,降低局部应用时对神经的刺激,促进中枢神经系统损伤后神经的修复和轴突的再生。方法:应用电纺丝技术制作的含ChABC及cAMP的聚碳酸亚丙酯及壳聚糖缓释组织工程支架,分析支架直径、载药量、包封率等参数,然后以磷酸盐缓冲液为体外释药介质观察组织工程支架的药物释放速度、药物的失活率及支架的降解速度。结果:ChABC和cAMP缓释组织工程支架在聚碳酸亚内酯质量浓度为8%、电压为10～15 kV、距离为15～20 cm时可以纺出纤维直径约3μm的平滑支架,单纯聚碳酸盐内酯纤维光滑,直径均一,壳聚糖微球光滑,聚碳酸亚内酯与壳聚糖混合后电纺丝形成的支架呈串珠样结构,其能缓慢持续释放有活性ChABC和cAMP,12 d后支架降解失重率约7%。结论:应用电纺丝方法成功制备含ChABC及cAMP的聚碳酸盐内酯及壳聚糖组织工程支架,其药物稳定释放,局部应用无神经刺激,可生物降解。     

多次交替浸渍法构筑簇状ZnO的PAN复合纳米纤维膜及其光催化性能

以聚丙烯腈（PAN）与氯化锌（ZnCl₂）作为前驱物,采用静电纺丝工艺制备PAN/ZnCl₂复合纳米纤维膜,分别采用多次冷热交替浸渍法和单次冷热静置浸渍法得到簇状PAN/ZnO-1和PAN/ZnO-2复合纳米纤维膜。利用扫描电镜（SEM）、傅里叶红外光谱（FT-IR）、X射线衍射（XRD）、X射线能量色散光谱（XPS）和热重分析仪（TG）对复合纳米纤维膜的表面形貌和微结构进行了表征,并以亚甲基蓝（MB）为污染物模型,评价其光催化降解性能。结果表明：经冷热交替浸渍后,纳米ZnO粒子均匀地附着在PAN纤维表面,尤其在PAN/ZnO-1复合纳米纤维膜表面还出现了花状ZnO粒子;相比单次冷热静置浸渍法处理的PAN/ZnO-2复合纳米纤维膜,经多次冷热交替浸渍的PAN/ZnO-1复合纳米纤维膜循环使用3次后对MB的降解率仍可达到90%以上,具有更好的光催化活性和循环使用性能。同时,MB溶液的初始质量浓度、催化剂用量和染料溶液的pH等因素对样品的的光催化降解率有一定影响。     

含非线性光学侧基的共聚酯的合成及相行为研究

通过熔融缩聚法合成了一类侧链含有非线性光学基元的共聚酯，用ＦＴＩＲ，ＮＭＲ和元素分析等对单体和聚合物进行了表征，并用ＤＳＣ，ＷＡＸＤ和偏光显微镜等对聚合物的相转变行为进行了研究，发现规整侧链的引入仍然结晶聚合物，对其结晶相的成因进行了初步分析。     

Preparation,Characterization and Release of Urea from Wheat Gluten Electrospun Membranes

Homogeneous and thin porous membranes composed of oriented fibers were obtained from wheat gluten (WG) using the electrospinning technique. SEM micrographs showed an asymmetric structure and some porosity, which, in addition to a small thickness of 40 μm, are desirable characteristics for the membranes’ potential application in release systems. The membranes were loaded with urea to obtain pastilles. FT-IR and DSC studies confirmed the existence of interactions via hydrogen bonding between urea and WG proteins. The pastilles were studied as prolonged-released systems of urea in water. The release of urea during the first 10 min was very fast; then, the rate of release decreased as it reached equilibrium at 300 min, with a total of ≈98% urea released. TGA analysis showed that the release system obtained is thermally stable up to a temperature of 117 °C. It was concluded that a prolonged-release system of urea could be satisfactorily produced using WG fibers obtained by electrospinning for potential application in agricultural crops.     

Melt extrusion with poorly soluble drugs

Melt extrusion (ME) over recent years has found widespread application as a viable drug delivery option in the drug development process. ME applications include taste masking, solid-state stability enhancement, sustained drug release and solubility enhancement. While ME can result in amorphous or crystalline solid dispersions depending upon several factors, solubility enhancement applications are centered around generating amorphous dispersions, primarily because of the free energy benefits they offer. In line with the purview of the current issue, this review assesses the utility of ME as a means of enhancing solubility of poorly soluble drugs/chemicals. The review describes major processing aspects of ME technology, definition and understanding of the amorphous state, manufacturability, analytical characterization and biopharmaceutical performance testing to better understand the strength and weakness of this formulation strategy for poorly soluble drugs. In addition, this paper highlights the potential advantages of employing a fusion of techniques, including pharmaceutical co-crystals and spray drying/solvent evaporation, facilitating the design of formulations of API exhibiting specific physico-chemical characteristics. Finally, the review presents some successful case studies of commercialized ME based products.     

Release pattern and structural integrity of lysozyme encapsulated in core–sheath structured poly(dl-lactide) ultrafine fibers prepared by emulsion electrospinning

The purpose of this study was to investigate the structural integrity, bioactivity and release patterns of lysozyme, as a model protein, encapsulated within the core-shell structured ultrafine fibers prepared by emulsion electrospinning. Electron microscopy and laser confocal scanning microscopy images demonstrated that the fibrous mats were very porous with integrally core-shell structured, bead-free, and randomly arrayed fibers. This structural property can pronouncedly alleviate the initial burst release and improve the sustainability of ultrafine fiber-based releasing devices. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and size exclusion chromatography were used to assess the primary structure of lysozyme, indicating that the ultra-sonication and electrospinning did not cause any remarkable denaturation of protein, while the core-shell structured fibers protected the structural integrity of encapsulated protein during incubation in the medium. Fourier transform infrared analyses showed that the electrospinning process had much less effect on the secondary structure of protein than ultra-sonication. The bioactivity assay indicated around 16% of specific activity loss during the emulsification procedure, and the protective effect of the shell materials on the activity of encapsulated protein. In vitro degradation showed that the protein entrapment led to more significant mass loss and higher molecular weight reduction.     

A review of key challenges of electrospun scaffolds for tissue‐engineering applications

Tissue engineering holds great promise to develop functional constructs resembling the structural organization of native tissues to improve or replace biological functions, with the ultimate goal of avoiding organ transplantation. In tissue engineering, cells are often seeded into artificial structures capable of supporting three‐dimensional (3D) tissue formation. An optimal scaffold for tissue‐engineering applications should mimic the mechanical and functional properties of the extracellular matrix (ECM) of those tissues to be regenerated. Amongst the various scaffolding techniques, electrospinning is an outstanding one which is capable of producing non‐woven fibrous structures with dimensional constituents similar to those of ECM fibres. In recent years, electrospinning has gained widespread interest as a potential tissue‐engineering scaffolding technique and has been discussed in detail in many studies. So why this review? Apart from their clear advantages and extensive use, electrospun scaffolds encounter some practical limitations, such as scarce cell infiltration and inadequate mechanical strength for load‐bearing applications. A number of solutions have been offered by different research groups to overcome the above‐mentioned limitations. In this review, we provide an overview of the limitations of electrospinning as a tissue‐engineered scaffolding technique, with emphasis on possible resolutions of those issues. Copyright © 2015 John Wiley & Sons, Ltd.     

静电纺纳米纤维支架在组织工程中的研究进展

静电纺丝技术(简称"电纺")是一种在高压电场作用下形成超细纤维的聚合物加工技术。通过控制电纺过程的各种参数可以制得性能不同的纳米纤维支架。本文主要介绍了电纺纳米纤维支架在皮肤、血管、骨、肌腱、神经等组织工程领域中的应用研究进展。     

α-K9P2W15Nb3O62纳米粒子的制备与表征

目的 对多金属氧酸盐α-K9P2W15Nb3O62的形貌和结构进行研究.方法 用高压静电纺丝和程序焙烧的方法,制备α-K9P2W15Nb3O62纳米粒子.结果 红外光谱,X-射线粉末衍射数据表明制备的纳米材料依然保持了Dawson-Wells结构,扫描电子显微镜显示焙烧后得到的α-K9P2W15Nb3O62纳米粒子直径约为220 nm.结论 成功获得了具有纳米粒子形貌的多金属氧酸盐:α-K9P2W15Nb3O62.     

Collagen nanofibres are a biomimetic substrate for the serum-free osteogenic differentiation of human adipose stem cells

Electrospinning has recently gained widespread attention as a process capable of producing nanoscale fibres that mimic native extracellular matrix. In this study, we compared the osteogenic differentiation behaviour of human adipose stem cells (ASCs) on a 3D nanofibre matrix of type I rat tail collagen (RTC) and a 2D RTC collagen-coated substrate, using a novel serum-free osteogenic medium. The serum-free medium significantly enhanced the numbers of proliferating cells in culture, compared to ASCs in traditional basal medium containing 10% animal serum, highlighting a potential clinical role for in vitro stem cell expansion. Osteogenic differentiation behaviour was assessed at days 7, 14 and 21 using quantitative real-time RT-PCR analysis of the osteogenic genes collagen I (Coll I), alkaline phosphatase (ALP), osteopontin (OP), osteonectin (ON), osteocalcin (OC) and core-binding factor-alpha (cbfa1). All genes were upregulated (>one-fold) in ASCs cultured on nanofibre scaffolds over 2D collagen coatings by day 21. Synthesis of mineralized extracellular matrix on the scaffolds was assessed on day 21 with Alizarin red staining. These studies demonstrate that 3D nanoscale morphology plays a critical role in regulating cell fate processes and in vitro osteogenic differentiation of ASCs under serum-free conditions.