乳液静电纺丝PLA/PEG微纳纤维膜的可控制备及负载亲疏水性药物的释放

采用低能相反转法,以聚乳酸(PLA)、疏水性药物喜树碱(CPT)溶液为油(O)相,以明胶水溶液、亲水性药物黄芪多糖(APS)为水(W)相,制备水包油(O/W)初乳液.通过控制聚乙二醇(PEG)的浓度和分子量制备O/W纺丝液,经乳液静电纺丝获得PLA/PEG微纳纤维膜.采用粒径分布、光学显微镜(OM)、扫描电子显微镜(SEM)、红外光谱(FTIR)、X射线衍射(XRD)、接触角测试和细胞毒性实验对初乳液和PLA/PEG微纳纤维膜进行表征,并通过激光共聚焦显微镜(CLSM)观察药物的分布情况.结果表明,通过乳液静电纺丝可成功制备亲水性良好的不同微纳结构的PLA/PEG微纳纤维膜.PLA/PEG微纳纤维膜形貌不同,亲水性存在差异,无细胞毒性.体外药物释放结果表明,与pH=6.8和7.4的释放介质相比,在pH=5.8的释放介质中,药物累积释放率较高,表明载药PLA/PEG微纳纤维膜能够有效减缓CPT的释放,而APS释放速率较快,可实现亲疏水性药物的差别性释放.     

基于壳聚糖的pH响应双重药物释放系统研究

以腙键连接的壳聚糖阿霉素前药偶联物(Chitosan-hz-DOX)为载体,通过物理包埋法制备了负载喜树碱(CPT)的双药共传递纳米输送体系(CPT-CS-DOX).通过紫外可见吸收光谱、动态光散射、透射扫描电镜等方法研究了体系的粒径、形貌、药物负载及释放性能,发现制备CPT-CS-DOX纳米颗粒的最佳CPT投放量为20%,其粒径随着Chitosan-hz-DOX中阿霉素(DOX)含量的增加而不断降低,共传递体系有效地抑制了DOX和CPT的早期泄露,并呈现出显著的p H依赖药物释放行为.利用Peppas方程对释放曲线进行分析,发现第一阶段DOX和CPT在中性环境中的释放遵循Fick扩散控制和溶胀控制机理,在酸性环境中CPT的释放机理保持不变,而DOX的释放则转变为聚合物松弛机理;第二阶段则两者均符合Fick扩散机理.     

pH响应性树枝状聚合物-金纳米粒子复合药物载体的制备

以表面接枝聚乙二醇链的聚酰胺胺树枝状聚合物(PEG-PAMAM)为纳米载体, 在其内部空腔包覆金纳米粒子, 在金纳米粒子表面连接硫辛酸改性的阿霉素(LA-DOX), 从而间接实现了抗癌药物在PEG-PAMAM内的高效负载. 同时, LA-DOX中的酰腙键提供pH响应性, 实现了药物的pH响应性释放. 紫外-可见(UV-Vis)光谱表明, 包覆金纳米粒子的PEG-PAMAM纳米载体对LA-DOX的负载能力显著增强. 体外细胞实验表明, 负载LA-DOX的树枝状聚合物-金纳米粒子复合药物载体具有较强的抗肿瘤能力.     

聚多巴胺-阿霉素纳米颗粒对癌细胞的化疗-光热治疗协同作用

通过在水相中加入乙醇和氨水, 将单分子多巴胺聚合成具有良好光热转换能力的聚多巴胺纳米颗粒(PDA), 并利用π-π作用与共价键作用, 将抗癌药物阿霉素(Dox)负载到聚多巴胺纳米颗粒的表面, 制备了聚多巴胺纳米颗粒负载阿霉素(PDA-Dox), 研究了PDA-Dox的药物缓释性能. 结果发现, PDA-Dox能够在酸性环境下增加药物释放. 细胞实验显示, PDA-Dox配合激光照射, 能够通过化疗和光热治疗高效地杀死癌细胞.     

荧光介孔二氧化硅纳米粒子的合成及药物运输（英文）

合成了荧光介孔二氧化硅纳米粒子(MSNs-FITC),并研究了其在持续药物释放和生物示踪成像方面的应用。首先,采用一步法合成出MSNs-FITC,结合SEM、TEM、FT-IR、XRD和氮气吸附脱附等表征技术进行表征。其次,将抗癌药物阿霉素(DOX)负载到MSNs-FITC中。载药粒子的药物释放行为具有明显的pH依赖性,酸性环境加速释放速率。同时,体外细胞毒性测试表明MSNs-FITC具有良好的生物相容性。激光共聚焦扫描显微镜(CLSM)图像表明,MSNs-FITC可以进入细胞并具有剂量依赖性,流式细胞术分析(FCM)进一步证明了这一结果。     

葡萄糖响应苯硼酸接枝壳聚糖盐酸盐抗肿瘤药物载体

通过分子改性向壳聚糖盐酸盐高分子链中引入苯硼酸基,合成了双亲性化合物苯硼酸接枝壳聚糖盐酸盐.细胞毒性实验表明苯硼酸接枝壳聚糖盐酸盐具有良好的细胞相容性.该双亲性化合物能够自组装成胶束聚集体,并包封疏水药物.以阿霉素为模型药物,研究了载药胶束聚集体的体外药物释放行为,结果表明,阿霉素在载药胶束聚集体内能够持续释放,且具有葡萄糖响应性.在生理p H=7.4和固体肿瘤弱酸性(p H=6.5)条件下,药物的释放速度十分缓慢,而当释放介质中有葡萄糖存在时,药物释放速度都明显加快.     

刺激响应共负载药物/基因微载体的制备

合成了聚乙烯亚胺接枝二茂铁(PEI-Fc)两亲聚合物, 采用水包油法制备包埋疏水性抗癌药阿霉素(DOX)的载药胶束, 并利用胶束表面正电荷的PEI链段有效缔合DNA, 获得尺寸合适、 表面带正电荷的阿霉素与基因共负载微载体. 在磷酸盐(PBS)缓冲溶液中, 共负载微载体能够缓慢释放出DOX. 在硝酸铈铵存在下, 二茂铁从疏水性转变为亲水性, 使载药胶束完全解离, 由于PEI-Fc与DNA之间的静电作用, 使基因超分子组装体稳定存在, 显示出很好的氧化响应特性. 细胞培养结果表明, 表面带正电荷的共负载微载体易被HepG2细胞内吞, 并可转染, 且随着DOX的释放逐渐杀死HepG2肝癌细胞, 为安全稳定、 具有刺激响应的药物与基因共负载微载体的制备提供了可行的途径.     

一种阿霉素/NO供体光敏纳米复合物的合成与性质研究

以硫化铜纳米晶(CuS-NCs)为核心,聚N-异丙基丙烯酰胺接枝壳聚糖(PNIPAM-g-CS)微粒为壳合成一种新型光敏纳米复合材料.在温度的调节下,N-异丙基丙烯酰胺(NIPAM)包覆CuS纳米晶,并接枝壳聚糖(CS),合成CuS杂PNIPAM-g-CS纳米复合材料.CuS在近红外光(980 nm)照射下具有光热效应,导致纳米复合物中PNIPAM-g-CS微粒受热体积收缩.负载阿霉素,这种纳米复合物就可作为光热诱导释放阿霉素的多功能纳米载体.再负载NO光敏供体(RBS),就可制备出阿霉素/RBS双负载的CuS杂PNIPAM-g-CS纳米载体.在可见光(365 nm)照射下,RBS光解释放NO.近红外光和可见光分别触发纳米载体释放阿霉素和NO,加上CuS纳米晶的光热效应,这种纳米载体可实现光触发双药物释放协同光热化疗杀伤肿瘤细胞.     

具有抗菌性能的载药复合微纳米纤维的制备及其结构和性能表征

利用静电纺丝技术制备了一种具有抗菌性能的氧化锌(ZnO)/聚乳酸(PLA)/聚己内酯(PCL)载药微纳米纤维膜,并通过扫描电子显微镜(SEM)、X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)分别对复合膜的表面形态、元素组成和化学结构进行表征。通过抗菌实验评价了复合膜的抗菌性能,用紫外分光光度计测试复合膜在体外的药物释放行为。结果显示,以物理共混的方式将ZnO和氢溴酸高乌甲素(LAH)成功载入复合微纳米纤维;与PLA/PCL复合微纳米纤维膜相比,ZnO/PLA/PCL复合微纳米纤维膜表现出更好的抗菌效率。当ZnO含量为10%(wt)时,复合微纳米纤维膜具有最佳的抗菌性能;药物释放性能结果表明,ZnO/PLA/PCL复合微纳米纤维膜具有良好的药物缓释性能。     

负载阿霉素的丝蛋白纳米微球

丝蛋白具有良好的生物相容性, 生物可降解性以及无免疫原性. 利用丝蛋白独特的亲疏水多嵌段共聚物结构特征和构象转变机制, 通过乙醇诱导和冷冻相结合的自组装方法制备得到丝蛋白纳米微球后, 再在纳米微球表面包覆阿霉素, 成功获得了负载阿霉素的丝蛋白纳米载药微球. 该载药丝蛋白纳米微球的尺寸为350～400 nm, 具有圆球形态并且分散性能良好; 其载药率为4.6%, 包封率大于90%, 在磷酸缓释溶液中的释放可达7天以上. 此外, 研究发现其缓释行为具有pH响应性, 在pH=5.0的磷酸缓冲溶液中的缓释量明显大于在pH=7.4的缓冲液中. 体外细胞培养结果显示, 纯丝蛋白纳米微球基本没有细胞毒性; 而负载有阿霉素的丝蛋白纳米微球能明显抑制癌细胞(Hela细胞)的增殖, 且24 h和48 h的培养结果表现出与单纯药物相同的药效. 因此, 该负载阿霉素的丝蛋白纳米微球在临床癌症淋巴化疗方面具有潜在的应用价值.     

聚(丙交酯-co-乙交酯)/β-磷酸三钙复合物的电纺研究

对生物可吸收聚(丙交酯-co-乙交酯)(poly(lactide-co-glycolide),PLGA)与β-磷酸三钙(-βTCP)复合物体系进行了电纺.研究了PLGA的浓度,-βTCP与PLGA比例,加料速度,电压,喷头与接收体之间的距离等因素对电纺过程的影响,制备出纳米纤维膜,并用扫描电镜(SEM)等对纤维膜进行表征.结果表明,电纺溶液浓度越高,或者加料速度越快,纳米纤维的直径越粗.力学实验显示,复合物中-βTCP的含量增加使纳米纤维膜的拉伸强度和杨氏模量下降.     

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.     

Preparation and characterization of poly(lactic‐co‐glycolic acid)/chitosan electrospun membrane containing amoxicillin‐loaded halloysite nanoclay

The main attitude of new wound dressings with biocompatible natural or synthetic polymers is improving and accelerating the healing process. In this study, halloysite nanotubes (HNTs) loaded with a model antibiotic drug, amoxicillin (AMX), were incorporated within poly(lactic‐co‐glycolic acid) (PLGA) solution that were electrospun with hydrophilic chitosan nanofibers simultaneously in two different syringes to make composite nanofibrous mat. The morphology, homogeneity, and fiber diameter of electrospun (PLGA/HNTs/AMX/chitosan) composite nanofibers were investigated by scanning electron microscopy and image J software. To evaluate the chemical structure, mechanical property, contact angle, and water absorption of samples, Fourier transform infrared spectroscopy, tensile testing, water contact angle, and immersion in phosphate buffer saline were utilized, respectively. Results indicated that incorporation of HNTs does not significantly alter nanofibers' morphology but rather increases their diameter, while the mechanical properties are improved because of its high modulus. Also, addition of natural hydrophilic polymer nanofibers (chitosan) enhanced the hydrophilicity property of samples. According to high‐performance liquid chromatography drug release analysis, HNTs as a good nanocarrier decreased initial burst release and showed controlled release behavior. MTT assay determined biocompatibility of PLGA/HNTs/AMX/chitosan. Copyright © 2016 John Wiley & Sons, Ltd.     

将源药包覆到聚己内酯超细纤维的芯部

采用同轴共纺技术,分别将白藜芦醇(Resveratrol,RT)和硫酸庆大霉素(Gentamycin Sulfate,GS)源药包覆在生物可降解的聚己内酯(PCL)超细(直径为几百纳米)纤维芯部.研究了这种纤维的制备过程以及它们的微观结构.这种复合纳米纤维可在医疗新产品开发中发挥作用,如用于制备新的羊肠线(体内手术伤口缝合线)或伤口敷布.     

Preparation and characterization of porous TiO_2/ZnO composite nanofibers via electrospinning

<正>Porous TiO_2/ZnO composite nanofibers have been successfully prepared by electrospinning technique for the first time.It was generated by calcining TiO_2/ZnCl_2/PVP[PVP:polyvinyl pyrrolidone)]nanofibers,which were electrospun from a mixture solution of TiO_2,ZnCl_2 and PVP.Transmission electron microscopy(TEM) and X-ray diffraction(XRD) analyses were used to identify the morphology of the TiO_2/ZnO nanofibers and a formation of inorganic TiO_2/ZnO fibers.The porous structure of the TiO_2/ZnO fibers was characterized by N_2 adsoption/desorption isotherm.Surface photovoltage spectroscopy(SPS) and photocatalytic activity measurements revealed advance properties of the porous TiO_2/ZnO composite nanofibers and the results were compared with pure TiO_2 nanofibers,pure ZnO nanofibers and TiO_2/ZnO nanoparticles.     

Desorption-limited mechanism of release from polymer nanofibers

This work examines the release of a model water-soluble compound from electrospun polymer nanofiber assemblies. Such release attracts attention in relation to biomedical applications, such as controlled drug delivery. It is also important for stem cell attachment and differentiation on biocompatible electrospun nanofiber scaffolds containing growth factors, which have been encapsulated by means of electrospinning. Typically, the release mechanism has been attributed to solid-state diffusion of the encapsulated compound from the fibers into the surrounding aqueous bath. Under this assumption, a 100% release of the encapsulated compound is expected in a certain (long) time. The present work focuses on certain cases where complete release does not happen, which suggests that solid-state diffusion may not be the primary mechanism at play. We show that in such cases the release rate can be explained by desorption of the embedded compound from nanopores in the fibers or from the outer surface of the fibers in contact with the water bath. After release, the water-soluble compound rapidly diffuses in water, whereas the release rate is determined by the limiting desorption stage. A model system of Rhodamine 610 chloride fluorescent dye embedded in electrospun monolithic poly(methylmethacrylate) (PMMA) or poly(caprolactone) (PCL) nanofibers, in nanofibers electrospun from PMMA/PCL blends, or in core-shell PMMA/PCL nanofibers is studied. Both the experimental results and theory point at the above mentioned desorption-related mechanism, and the predicted characteristic time, release rate, and effective diffusion coefficient agree fairly well with the experimental data. A practically important outcome of this surface release mechanism is that only the compound on the fiber and pore surfaces can be released, whereas the material encapsulated in the bulk cannot be freed within the time scales characteristic of the present experiments (days to months). Consequently, in such cases, complete release is impossible. We also demonstrate how the release rate can be manipulated by the polymer content and molecular weight affecting nanoporosity and the desorption enthalpy, as well as by the nanofiber structure (monolithic fibers, fibers from polymer blends, and core-shell fibers). In particular, it is shown that, by manipulating the above parameters, release times from tens of hours to months can be attained.     

Synthesis and properties of ZnO nanofibers prepared by electrospinning

ZnO nanofibers were prepared from zinc acetate/polyvinyl alcohol (PVA) by electrospun method. The morphological features, crystallinity, mechanical and optical properties of the ZnO nanofibers were studied. The results show the specific surface area of the ZnO nanofibers was influenced by the electrospun conditions. The specific surface area reached 389.7 m²g⁻¹ as the average diameter was 232 nm. The XRD date reveals the nanofibers consist of a single phase of well-crystallized ZnO with hexagonal structure. The elastic modulus of a single ZnO nanofiber was also characterized by nano-scale three-point bending test.     

A review on electrospun polymeric nanofibers: Production parameters and potential applications

This review deals with electrospun nanofibers and their applications in several fields. Nanofibers have mainly been produced via electrospinning technique due to the simple, cost-effective, and versatile setup. Electrospinning is defined as a process, which produces fibers from its polymer solutions under exposure of high electric field voltage. The technique needs optimization of several parameters such solution, processing and ambient parameters to refine nanofiber morphology, diameter and porosity. The basic technique has been modified to produce composite fibers and to increase production capacity. Nanofiber characterization methods are summarized with examples. The relation between electrospinning and electrospraying is discussed. Nanofibers have the ability to form highly porous mesh with large surface to volume ratio enhancing its performance for various applications such as water filtration, tissue engineering scaffold, wounds, fiber composites, drug release and protective clothes. Single nanofibers could potentially be used as soft microrobots for drug delivery. Finally, results from modeling and simulations are illustrated.     

In situ growth of ZnO nanocrystals from solid electrospun nanofiber matrixes

Porous fiber membranes consisting of 1D assemblies of ZnO nanocrystal-supported poly(vinyl alcohol) (PVA) nanofibers are described. These hybrid nanofiber membranes were assembled by first electrospinning a ZnO precursor-containing PVA aqueous solution. Subsequently, the electrospun composite nanofibers were submerged in a basic ethanol solution. As a result, ZnO precursors in solid PVA matrixes were hydrolyzed to generate ZnO crystals residing on the fiber surfaces. Photoluminescence spectroscopy analysis demonstrated the as-hydrolyzed fiber membranes possess white luminescence. Furthermore, the ZnO-encapsulated PVA nanofibers were prepared by directly electrospinning a ZnO nanocrystal-containing PVA solution as the contrast of the as-hydrolyzed hybrid nanofibers. The surface photovoltage spectroscopy (SPS) confirmed that the as-hydrolyzed hybrid fiber membranes had a strong SPS response, but the directly spun fiber membranes did not have any SPS response. This can be attributed to the favorable structure of the hydrolyzed hybrid nanofibers, that is, the surface residence of ZnO permits ZnO crystals to make direct contact with ITO electrodes to transfer the photogenerated electron originating from ZnO to ITO electrodes. By contrast, the transfer of the photogenerated electron is limited by PVA matrixes in the directly spun fiber system.     

Tunable self-assembled stereocomplexed-polylactic acid nanoparticles as a drug carrier

In this study, a model hydrophilic drug (porphyrin) was encapsulated within hydrophobic polylactic acid (PLA) nanoparticles (NPs) with different crystallinity and the relevant release behaviors were investigated. The crystalline modification was done using a modified nanoprecipitation method, where homo and stereocomplexed PLA NPs with different average diameters based on varying polymer concentrations and solvent/nonsolvent ratios (S/N) were prepared. Entrapment efficiency and drug release of sterocomplexed-PLA NPs were compared with neat poly(l -lactic acid) (PLLA) NPs. Furthermore, to get the more sustained release, porphyrin-loaded NPs were immobilized within electrospun poly(d ,l -lactide-co-glycolide (PLGA) nanofibers (NFs). Outcomes revealed that solution concentration and solvent/nonsolvent ratio play significant roles in the formation of homo and stereocomplexed NPs. On the other hand, it was found that the formation of stereocrystals did not significantly affect the size and morphology of NPs compared with neat NPs. With regard to the entrapment efficiency and drug content, stereocomplexd-PLA NPs behave relatively the same as neat PLLA NPs while the more sustained release was observed for stereocomplexed NPs. Also, it was observed that electrospinning of PLGA solution loaded by NPs led to the uniform distribution of NPs into PLGA fibers. Encapsulating the drug-loaded NPs into nanofibers decreased the rate of drug release by 50% after 24 h, compared with direct loading of drug into PLGA NFs. We conclude that it is possible to tune the entrapment efficiency and modify the release rate of the drug by giving small changes in the process parameters without altering the physical properties of the original drug substance and polymer.