静电纺丝制备聚己内酯载药纤维工艺参数研究

选用聚己内酯作为载体材料、5-氟尿嘧啶作为承载药物,研究了静电纺丝过程中纺丝液浓度、纺丝电压及收集距离对纤维直径的影响,对制备的聚己内酯载药纤维膜进行元素检测分析及力学性能测试,通过体外药物释放实验,验证了聚己内酯载药纤维膜药物控释的效果.结果表明,随着纺丝液的浓度和收集距离增加,纤维的平均直径增大;随着纺丝电压增加,...     

静电纺聚乳酸纳米纤维的制备及其孔结构调控

为了调控聚乳酸(PLA)纳米纤维的孔结构,采用静电纺丝技术,以PLA母粒为原料,三氯甲烷(CF)和N,N-二甲基甲酰胺(DMF)按一定比例混合的溶液为溶剂,制备了平均直径在1.37μm的PLA纳米纤维,并对其结构进行表征。结果表明,PLA纳米纤维的平均直径随着纺丝液中CF含量、聚合物浓度、环境湿度的增加而增大;随纺丝电压和灌注速度的增大而呈减小的趋势。同时,环境湿度对纤维表面孔结构有显著影响。随着湿度的增加,纤维表面孔的分布密度增加,且形状由圆形转变为椭圆形。此外,与表面光滑的PLA纳米纤维(2.4 m²/g)相比,所制备的PLA多孔纤维的比表面积提升了10倍(24.0 m²/g)。     

熔体微分静电纺PLA/PEG/SDBS纤维膜的制备及无动力水输运性能分析

亲水纤维膜具有毛细作用，水分可以在纤维中沿着不同方向进行输送，是一种理想的土壤保湿材料。采用熔体微分静电纺丝技术，在聚乳酸(PLA)中引入亲水剂十二烷基苯磺酸钠(SDBS)及增塑剂聚乙二醇(PEG),制备亲水性PLA/PEG/SDBS纤维膜，探究复合材料中SDBS含量对纤维微观形貌及纤维膜亲水性能的影响。结果表明，随着共混体系中SDBS含量的增加，平均纤维直径呈先增大后减小，纤维膜吸水倍率、平均输水速率及平均芯吸高度总体呈上升趋势。在纺丝电压为35 kV、纺丝距离8 cm的工艺参数下，当共混体系中SDBS含量为1.5%时，平均纤维直径为3.38μm、吸水倍率为19.37倍、平均输水速率为6 g/min、平均芯吸高度为10.23 cm。利用熔体微分电纺技术实现亲水性PLA/PEG/SDBS纤维膜的制备，无动力水输运性能的研究为其在土壤微灌、光热界面蒸发等领域中的应用提供了基础。     

电纺制备聚乳酸/纳米氧化镓复合纤维膜及其性能研究

采用静电纺丝技术分别制备了纯聚乳酸（PLA）纤维膜及不同纳米氧化镓（NGO）含量的PLA/NGO复合纤维膜,并通过扫描电子显微镜、差示扫描量热仪、电子万能试验机等仪器对复合纤维膜的表面形貌、结晶性能、力学性能进行了表征,还利用震荡烧瓶法对复合纤维膜的抗菌性能进行了评价。结果表明,随着NGO用量的增加,复合纤维膜的纤维的直径逐渐减小,直径分布变宽;随着NGO用量的增加,复合纤维膜的熔融温度和结晶度均出现先上升后下降的趋势;复合纤维膜的断裂强度和弹性模量随着NGO用量的增加先增加后减小,而断裂伸长率先降低后升高;PLA/NGO复合纤维膜对金黄色葡萄球菌具有良好的抑菌效果,且随着NGO含量的增加抗菌效果增强。     

多孔功能性PLA/纳米氧化铈复合纤维的制备及性能

利用静电纺丝法制备了不同CeO2含量的PLA/CeO2复合纤维,并系统的研究了CeO2含量对PLA/CeO2静电纺丝液性质的影响,电压和CeO2含量对于复合纤维直径的影响及CeO2含量对PLA/CeO2复合纤维膜细胞增殖的影响。结果表明,随着CeO2用量的增加,静电纺丝液的表面张力逐渐下降,电导率逐渐提高;PLA静电纺丝纤维的直径随纺丝电压的升高先减小后增加,且电压较高时,纤维直径分布逐渐变宽;CeO2能够有效降低纤维的直径,但用量过多时会导致纤维直径增加,分布变宽;CeO2能够显著地促进PLA结晶,并且从多重熔融峰转变为单重熔融峰;PLA/CeO2复合薄膜具有良好的生物相容性,随CeO2含量的增加,对细胞增殖的促进作用更加明显。     

电纺PVA/HBPL荧光纳米纤维膜的制备及其结构性能表征

以水为溶剂,配制质量分数6%的聚乙烯醇(PVA)水溶液,将超支化聚赖氨酸(HBPL)按PVA∶HBPL质量比分别为9∶1,7∶1,5∶1加入PVA水溶液中共混均匀,制得纺丝溶液,在直流电压22 kV、推进速率为0.3 mL/h、接收距离为14.5 cm、30℃的条件下进行静电纺丝制得PVA/HBPL荧光纳米纤维膜,并对其结构性能进行表征。结果表明:PVA/HBPL荧光纳米纤维膜的纤维表面光滑,粗细均匀,平均直径为247~321 nm,在波长392 nm的激光激发下,PVA/HBPL荧光纳米纤维膜的发射波长为438 nm,荧光强度为40.80~98.20,荧光现象明显;随着HBPL含量的增加,PVA/HBPL荧光纳米纤维膜的纤维直径分布变宽,平均直径增加,熔点与熔融焓降低,荧光强度增强,拉伸强度先增加后减小,断裂伸长率降低。     

基于静电纺丝技术的PLGA载药纳米纤维膜的制备工艺

同轴静电纺丝法制备的聚乳酸-乙醇酸(PLGA)纳米纤维具有良好的生物相容性和生物可降解性, 加之其高孔隙率和高透氧率, 使其能成为优良的药物载体。本文初步摸索了PLGA的同轴静电纺丝的工艺条件, 并通过同轴静电纺丝法制备了PLGA载氟比洛芬酯(FA)的纳米纤维膜, 应用扫描电子显微镜、红外光谱分析观察纤维的表观形貌并确定其微观结构。重点探究了不同溶剂配比的混合溶剂对载药纤维膜药物释放性能影响。研究结果表明在U⁺为+15.00kV, U^-为-2.50kV, 接受距离为15cm, 壳层推进速度为0.4mm/min, 芯层推进速度为0.1mm/min进行静电纺丝时, 所制备的PLGA(壳)/PVP+FA(核)复合载药纤维膜壳核结构良好, 且成功载了约0.5%的FA。当改变壳层混合溶剂(DCM和DMF)和芯层混合溶剂(无水乙醇和DMF)体积比时, 纤维直径会随着DMF的减少而增大。     

细菌纤维素/聚乳酸复合膜制备及性能

以聚乳酸(PLA)为原料,利用细菌纤维素(BC)生产菌株发酵制得BC/PLA复合膜。通过对BC/PLA复合膜制备过程中发酵时间、纺膜速率、PLA溶液用量等因素的考察,以BC/PLA复合膜载药率为指标,进行了BC/PLA复合膜制备工艺的优化;利用FTIR、TG、拉力实验、XRD及SEM对BC、PLA及BC/PLA复合膜化学基团、热性能、力学性能、结晶度及表面形貌进行了分析;对BC/PLA复合膜载药及释药过程进行了研究。结果表明,PLA溶液用量对BC/PLA复合膜载药率影响较小,BC/PLA复合膜最优制备工艺为:纺膜速率0.15 mm/s,发酵时间36h,所制备BC/PLA复合膜在15mg/L双氯芬酸钾药液中最大载药率为2.51mg/g。FTIR、TG、拉力实验、XRD及SEM结果表明,BC与PLA可以成功复合,从而改善PLA的热性能及力学性能,所制备BC/PLA复合膜具有三维网状多孔结构。载药BC/PLA复合膜药物释放过程符合一级释放动力学模型。     

溶液性质对电纺聚乳酸/茶多酚复合纳米纤维膜形貌的影响

为了研究静电纺丝溶液性质对聚乳酸(PLA)/茶多酚(TP)复合纳米纤维膜的形貌与直径的影响,本文借助扫描电子显微镜(SEM)观察不同纺丝溶液条件下纳米纤维膜的外观形貌并计算纤维直径。结果表明:当PLA溶质质量分数为10%时,纤维成纤性最好。而纺丝溶剂采用二氯甲烷(DCM)和N,N-二甲基甲酰胺(DMF)的混合溶剂时,纤维形貌改善明显。同时不同PLA/TP质量混比条件下的纤维直径在380~854nm之间。     

PVP/PLA乳液静电纺丝成形及纤维毡亲水性能研究

利用乳液静电纺丝可制备一定复合结构的共混纤维,且可通过调控乳液的组成而实现聚合物溶液在低浓度下的静电纺丝成形。以聚乙烯基吡咯烷酮(PVP)水溶液为分散相,聚乳酸(PLA)氯仿溶液为基体相,制备不同水相比例的PVP/PLA乳液,研究了PVP/PLA乳液静电纺丝成形及其纤维毡的亲水性能。结果表明:乳液体系中PVP水相的加入可使PLA乳液在远低于其单独可纺溶液浓度下纺丝成形,所得纳米纤维随着PVP水相比例的提高而表现出纤维直径增加,并发生纤维集结成束,PVP大部分分布在复合纤维毡的表层,纤维毡呈现明显的透水性能;PVP的加入可有效改善PLA纳米纤维毡的亲水性能。     

Multifunctional ternary drug‐loaded electrospun scaffolds

Multifunctional electrospun scaffolds were prepared from two polylactide (PLA) grades having slightly different d ‐lactide content (4.2 wt % and 2.0 wt %). Triclosan (TCS), ketoprofen (KTP), and p‐coumaric acid (CUM) were selected as bactericide, anti‐inflammatory, and antioxidant agents, respectively. Single, binary, and ternary drug‐loaded microfibers having a unimodal diameter distribution could be prepared using a common chloroform:acetone:dimethylsulfoxide mixture and similar operational parameters (i.e., voltage, flow rate, and tip–collector distance). FTIR spectra were sensitive to the low amount of drugs loaded and even showed slight differences in PLA conformation. DSC heating scans clearly demonstrated the ability of electrospinning to induce molecular orientation of PLA and also the nucleation effect of incorporated drugs to induce crystallization. Thus, crystallinity of binary drug‐loaded scaffolds was significantly higher than observed for unloaded samples. Release behavior of the three drugs from loaded scaffolds and PLA matrices in PBS:ethanol medium was evaluated. A rapid release was always detected, together with partial drug retention which was higher when the more stereoregular PLA matrix was employed. A strong bactericidal effect was found when scaffolds were loaded with 3 wt/vol % of TCS, but incorporation of a small percentage of KTP (i.e., 1 wt/vol %) had a bacteriostatic effect even in the absence of TCS. The inherent cytotoxicity of TCS could be well neutralized by enhancing cell viability by incorporation of CUM and/or KTP. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42751.     

Sweet Potato Starch Microparticles as Controlled Drug Release Carriers: Preparation and In Vitro Drug Release

The aim of this study was to investigate the in vitro drug release behavior of sweet potato starch (SPS) microparticles intended for controlled drug delivery applications. Diclofenac sodium (DS) was used as a model drug candidate in the present study. SPS microparticles were prepared using a spray-drying technique by varying the polymer concentration and drug loading. The mean particles size of drug-loaded spray-dried SPS microparticles was between 10.3 and 13.1 µm. The mean particle size increased slightly with increase in the concentration of SPS. The mean particle size of spray-dried SPS microparticles increased from 10.3 to 13.1 µm when the concentration of SPS increased from 2 to 4% w/v. Under the current spray-drying conditions, the percentage yield of spray-dried SPS microparticles did not vary much among the various formulations and it was between 65.2 and 70.1%. The encapsulation efficiencies of SPS microparticles formulations was between 95.1–98.2%, suggesting good encapsulating ability of the SPS polymer by spary drying. Drug release from all the formulations of spray-dried SPS microparticles was controlled over period of 6 h. The cumulative amount of drug release from the spray-dried SPS microparticles decreased with an increase in the concentration of SPS, while it increases as the drug loading is increased. Release of the drug from spray-dried SPS microparticles followed Fick's law of diffusion since a good correlation coefficient (R²) was observed with the Higuchi plots (R² = 0.9928 to 0.9979).     

Evaluation of drug release property and blood compatibility of aspirin-loaded electrospun PLA/RSF composite nanofibers

In this paper, PLA/RSF with different mass ratios and aspirin-loaded PLA/RSF composite nanofiber membranes were prepared via electrospinning. Polylactic acid (PLA) and regenerated silk fibroin (RSF) were dissolved in trifluoroacetic acid and dichloromethane at a volume ratio of 70/30. The structure analysis made by Fourier transform infrared spectroscopy (FTIR) suggested that PLA and RSF blended very well in the composite membranes. In addition, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the average diameters of composite nanofibers were between 80 and 210 nm. Furthermore, the composite nanofibers had better uniformity in the range of the experiment, and the average diameter of composite nanofibers decreased with the increase of aspirin content. Wettability performance was investigated via contact water angle meter; the hydrophilic property of composite membranes had been improved with the existence of SF. Drug release property was tested by detecting the absorbency of drug in PBS solution via UV–visible spectroscopy, and the results showed that drug release rate reached the maximum when the mass ratio of PLA/RSF was 8/3. With the raise of aspirin content, the drug release rate increased. The in vitro anticoagulation behavior was studied by static platelet adhesion test. The results revealed that the anticoagulation property of composite membranes was superior to that of pure PLA nanofiber membranes. The anticoagulation property significantly improved in the presence of aspirin.     

Investigation of bubble diameter and flow regime between water and dilute aqueous ethanol solutions in an airlift reactor

In this study, the effect of ethanol addition into pure water and its concentration on bubble diameter, gas hold-up and flow regimes were investigated in an airlift reactor. Air and water with ethanol (concentration ranging from 0%–1%, v/v) were as dispersed and continuous phases, respectively. Superficial gas velocity was considered as an effective parameter. Bubble size distribution was measured by photography and picture analysis at various concentrations of ethanol and various velocities of gas. Alcohol concentration enhancement caused bubble diameter to decrease. Furthermore, the bubbles diameter in pure water was nearly 4 times higher than that of ethanol with concentration of 1% (v/v) and also was 3.4 times higher than that of ethanol with concentration of 0.25% (v/v) at the highest aeration gas velocity inlet. For ethanol solutions in lower superficial gas velocity, a homogenous flow regime was observed. This trend continued to inlet gas velocity of about 0.4 cm/s. The transition flow regime occurred after this datum although in pure water, a homogenous flow regime was observed up to a superficial gas velocity of 0.7 cm/s. The gas hold-up in dilute ethanol solutions were more than (around 2 times) that of pure water and increased with increasing concentration of ethanol in those solutions.     

Fabrication and sustained release properties of poly(ε-caprolactone) electrospun fibers loaded with layered double hydroxide nanoparticles intercalated with amoxicillin

Amoxicillin (AMOX) was intercalated in layered double hydroxide (LDH) nanoparticles by coprecipitation. LDH intercalated with AMOX (LDH/AMOX) was successfully encapsulated at different concentrations into poly(ε-caprolactone) (PCL) by the electrospinning technique. Mats of non-woven PCL fibers loaded with LDH/AMOX were obtained and characterized in terms of morphology and in vitro release. The fibrous structure of a pristine PCL sample was composed of individual, uniform, and randomly oriented fibers with an average diameter ranging around 0.8 μm. The addition of LDH/AMOX at different concentrations caused a slight increase of the average diameter and the presence of rare beads possibly due to clusters of the nano-hybrid on the surface of the microfibers.The release curves present a sustained release behavior, although an initial rapid drug release was found. The initial high-rate drug release period was followed by a second step in which the release is slow, extending for long time. The comparison of the release curves showed that the release of AMOX protected into the clay is slower than the release of the drug alone.     

5-氟尿嘧啶明胶微球的制备、表征及释药性能

为了获得粒径为50～100μm的5-氟尿嘧啶／明胶微球（5-Fu／GMs）,采用乳化一化学交联法,讨论了5-Fu用量、乳化剂浓度和水／油比等因素对微球平均粒径、载药量及包封率等的影响。结果表明,5-Fu／明胶质量比为0．5,乳化剂浓度为0．5％和水／油相体积比为1／10时,可获得最大的载药量30．1％和包封率90．2％。体外释药性能表明5-氟尿嘧啶明胶微球具有明显的药物缓释作用。     

New Method to Prepare Mitomycin C Loaded PLA-Nanoparticles with High Drug Entrapment Efficiency

The classical utilized double emulsion solvent diffusion technique for encapsulating water soluble Mitomycin C (MMC) in PLA nanoparticles suffers from low encapsulation efficiency because of the drug rapid partitioning to the external aqueous phase. In this paper, MMC loaded PLA nanoparticles were prepared by a new single emulsion solvent evaporation method, in which soybean phosphatidylcholine (SPC) was employed to improve the liposolubility of MMC by formation of MMC–SPC complex. Four main influential factors based on the results of a single-factor test, namely, PLA molecular weight, ratio of PLA to SPC (wt/wt) and MMC to SPC (wt/wt), volume ratio of oil phase to water phase, were evaluated using an orthogonal design with respect to drug entrapment efficiency. The drug release study was performed in pH 7.2 PBS at 37 °C with drug analysis using UV/vis spectrometer at 365 nm. MMC–PLA particles prepared by classical method were used as comparison. The formulated MMC–SPC–PLA nanoparticles under optimized condition are found to be relatively uniform in size (594 nm) with up to 94.8% of drug entrapment efficiency compared to 6.44 μm of PLA–MMC microparticles with 34.5% of drug entrapment efficiency. The release of MMC shows biphasic with an initial burst effect, followed by a cumulated drug release over 30 days is 50.17% for PLA–MMC–SPC nanoparticles, and 74.1% for PLA–MMC particles. The IR analysis of MMC–SPC complex shows that their high liposolubility may be attributed to some weak physical interaction between MMC and SPC during the formation of the complex. It is concluded that the new method is advantageous in terms of smaller size, lower size distribution, higher encapsulation yield, and longer sustained drug release in comparison to classical method.     

用AFM研究静电纺丝负载药物的缓释机制

研究了壳聚糖(CS)-聚环氧乙烯(PEO)和聚乳酸(PLA)-CS载药电纺纤维的牛血清蛋白(BSA)释放行为. 利用原子力显微镜(AFM)观察了纤维在模拟体液中的分解与溶胀行为. CS-PEO纤维在模拟体液中分解10 h时BSA总释放量高达96%, 1 d后纤维结构基本分解完全,在缓冲液中浸泡120 min后纤维直径由浸泡10 min时的0.727 mm增大到1.43 mm,纤维表面发生明显分解. CS-PEO和PLA-CS纤维具有不同的药物释放机制,CS-PEO载药纤维的药物释放主要是纤维结构快速分解,BSA扩散作用相对较弱;而后者在溶液中没有明显分解,浸泡30 d后纤维直径从浸泡1 d时的1.9 mm增至2.8 mm,BSA释放量不到总量的50%,其药物释放机制可能主要依靠BSA的扩散.     

工艺条件对PBAT/PLA原位成纤共混体系结构与性能的影响

将质量比为80/20的PBAT/PLA共混物在单螺杆挤出流延成型机中通过调控工艺条件（口模温度、拉伸速度）直接熔融共混制备PBAT/PLA原位成纤共混薄膜。结果表明,在较低口模温度时,随着拉伸速度的提高,PLA微纤细化程度加大,结晶度先提高后降低,纵向拉伸强度先增加后减小,力学性能各向异性明显。在口模温度为150℃、拉伸速度为5.0 m/min时,共混体系中PLA成纤效果最明显;PBAT和PLA的结晶度最高分别为4.8%和23.7%;纵向拉伸强度达到29.8 MPa,比纯PBAT提高了41%。