纳米金属有机骨架ZIF-90的制备及载药性能研究

金属有机骨架材料是由金属离子与有机配体通过自组装过程杂化生成的一类具有周期性多维网状结构的多孔材料,在催化、传感、气体储存和载药等方面均表现出了优异的性能。采用一种新的实验方法(超声-搅拌法)并通过优化反应条件制备了粒径在300nm以下的ZIF-90纳米材料,利用傅里叶红外光谱(FTIR)、粉末X射线衍射(XRD)确定了金属有机骨架的结构,利用扫描电子显微镜(SEM)确定了材料的形貌和粒径。ZIF-90纳米药物载体装载和释放抗癌药物5-氟尿嘧啶的实验结果表明,该材料装载药物的能力最高可达1.245g/g,药物缓释时长达15h,释放率达到95%以上。该药物载体在不同pH值下的稳定性实验结果表明,该药物载体可在接近肿瘤细胞的酸性条件下通过骨架坍塌的方式快速释放药物,具有肿瘤靶向传递药物的能力。     

改性ZIF90-Pebax混合基质膜的制备及CO2分离性能

以骨架结构极稳定的ZIF-90作为掺杂材料,通过后合成修饰(PSM)技术使用不同链长结构的胺烷对ZIF-90进行表面修饰,并探究不同链长结构的改性剂及其用量对ZIF-90与其Pebax基混合基质膜气体分离性能的影响.实验发现,胺烷的改性不仅不会改变ZIF-90的晶体结构,还能够在ZIF-90表面形成"绒毛"状结构,形成有机-有机高相容的界面.除此之外,该"绒毛"结构虽然会降低填料本身的比表面积及孔体积,但是在合适的长度与数量下会与聚合物产生某种特殊的有益于气体分离的相互作用,可以明显提高混合基质膜的分离性能.使用正丙胺改性的PZ90/Pebax系列混合基质膜相较于纯ZIF-90/Pebax, CO_2/N_2选择性与CO_2渗透性都有不同程度的提高,改性程度为20%时分离性能最佳,CO_2/N_2选择性为70,CO_2渗透率达到140 Barrer,与纯Pebax相比分别提高了45.8%和79.4%,接近2008年Robeson上限.     

氟化改性ZIF-8-90杂化膜的制备及其渗透汽化脱醇研究

有机-无机杂化膜是目前膜分离研究的热点,但是有机基体-无机粒子之间的界面缺陷是目前面临的重要问题.使用五氟丙胺改性ZIF-8-90粒子(F-ZIF-8-90),为了改善有机基体-ZIF-8-90之间的界面缺陷和提高ZIF-8-90的疏水性,红外谱图证实了五氟丙胺的成功接枝.以F-ZIF-8-90为填充料,制备了一系列Pebax 2533/F-ZIF-8-90杂化膜,考察了杂化膜的形貌结构、疏水性能和渗透汽化性能.研究结果表明,F-ZIF-8-90填充质量分数为5%时,70℃测试条件下杂化膜对质量分数5%乙醇水溶液的渗透通量最高可达201.5 g/(m~2·h),对应的分离因子为5.4.相比较纯Pebax 2355膜,渗透通量和分离因子分别提高了24.1%和151.9%,打破了渗透通量和分离因子相互制约的效应.     

ZIF材料对碘的吸附特性研究

核废水中的放射性碘对人类健康和环境有严重的危害, 但是由于碘在水中以多种形式存在, 很难准确测定其在水中的含量。开发能够准确测定水中碘单质含量的方法, 制备有效去除碘单质的材料对保护环境和人类健康尤其重要。为此, 本研究首先提出了用环己烷萃取法测定碘单质浓度的方法, 并且制备了两种沸石咪唑骨架材料ZIF-8和ZIF-67, 研究了ZIF-8和ZIF-67对水环境中碘的吸附行为。利用分析仪器对ZIF-8和ZIF-67材料进行了表征。结果表明: 两种材料都具有良好的化学结构和较大的比表面积。吸附动力学实验结果表明, 60 min内, 两种材料对碘的吸附可以达到平衡, 吸附行为更好地符合拟二级动力学模型。吸附热力学结果表明, 两种材料在水中对碘的吸附过程均为线性吸附。ZIF-8和ZIF-67材料对碘单质的吸附量可高达2000 mg·g ^-1。     

ZIF-67@PDA/含氟聚酰亚胺混合基质膜的制备及其气体分离性能

金属有机框架材料(MOF)/聚合物混合基质膜(MMMs)通过结合MOF的分子筛效应和聚合物基质成本较低、加工性能好、机械强度高的特征,使其在气体分离领域展现出巨大的应用前景。然而由于MOF在聚合物基体中存在分散性差问题,极大地限制了其应用。采用溶剂热法合成金属框架材料ZIF-67,并通过溶液氧化法在ZIF-67表面修饰聚多巴胺(PDA)层制备ZIF-67@PDA纳米多孔材料。以4,4’-二氨基二苯醚-2,2’-双(3,4-二羧酸)六氟丙烷二酐(ODA-6 FDA)型含氟聚酰亚胺(FPI)为基体、ZIF-67和ZIF-67@PDA为填料,制备不同质量分数的ZIF-67/FPI和ZIF-67@PDA/FPI。通过FTIR、WAXD、TGA、SEM、比表面和孔径分布分析仪、气体渗透仪等测试对MMMs的结构和性能进行表征并测试了N₂、O₂、CO₂、He 4种气体的渗透性。结果表明：经聚多巴胺修饰后的纳米微孔材料ZIF-67在聚合物基体中能均匀分散并为气体分子的通过提供快速通道,且表现出良好的热稳定性。ZIF-67@PDA对CO<...     

ZIF-8/PVA静电纺丝膜的制备及其吸附性能

采用静电纺丝技术成功制备出沸石咪唑骨架材料(ZIF-8)/聚乙烯醇(PVA)静电纺丝膜。分别探究和优化了PVA浓度、纺丝电压、接收距离等参数对纤维膜形态结构的影响。对复合纳米纤维膜进行了形貌表征和成分分析。实验发现在ZIF-8的浓度为10wt%条件下,当PVA的浓度为7wt%、电压为40kV、接收距离为16cm时,可得到可纺性最好、形态均匀的纳米纤维膜,膜纤维的平均直径在240nm左右。将已经制备成功的ZIF-8/PVA复合纳米纤维用于吸附刚果红,在12h内吸附容量可达86mg/g,显示出良好的吸附能力。     

ZIF-8@PAN纳米纤维膜基多孔碳材料的制备及对镉离子的吸附性能

主要将通过磁控溅射技术制备所得的氧化锌@聚丙烯腈(ZnO@PAN)静电纺丝纳米纤维膜材料,利用溶剂热反应合成金属有机框架材料ZIF-8@聚丙烯腈(ZIF-8@PAN)纳米纤维膜材料,后经过900℃高温煅烧工序制备ZIF-8@PAN纳米纤维膜基多孔碳材料,并将其应用于水体中重金属离子镉的吸附。X射线衍射、红外光谱、扫描电镜分析表征结果表明,ZIF-8成功地在PAN纳米纤维膜上原位生长,经过高温煅烧,ZIF-8的结构并未明显改变。ZIF-8@PAN纳米纤维膜基多孔碳材料在水溶液中对镉离子具有良好的吸附效果。探究证明,吸附过程中,在溶液为中性条件下,且水浴加热35℃时,镉离子吸附效果最好,吸附效率最高可达到88%左右。     

ZIF-8-SiO2的制备及其对U(Ⅵ)的吸附

以沸石咪唑酯骨架结构材料ZIF-8及硅酸四乙酯(TEOS)为原料制备ZIF-8-SiO_2复合材料,并采用XRD、SEM、EDS等方法对ZIF-8-SiO_2的结构及吸附U(Ⅵ)前后的形貌进行表征,结果表明ZIF-8-SiO_2成功制备且对U(Ⅵ)具有良好的吸附作用。以静态吸附实验,分别考察了pH值、时间、温度、溶液初始铀浓度、盐浓度及超高压环境等对ZIF-8-SiO_2吸附性能的影响。由实验结果可得,在初始浓度为80 mg·L~(-1)时,25℃下ZIF-8-SiO_2对U(Ⅵ)的最大实际吸附量为498 mg·g~(-1),根据Langmuir模型拟合结果分析得出,ZIF-8-SiO_2对U(Ⅵ)的理论吸附量最高可达678.5 mg·g~(-1),且在200～500 MPa范围内,压强越高越有利于吸附。通过FTIR、XPS等方法对ZIF-8-SiO_2吸附铀酰离子前后的结构进行分析,探究该吸附过程中可能存在的吸附机制。     

ZIF-8-SiO2的制备及其对U(VI)的吸附

以沸石咪唑酯骨架结构材料ZIF-8及硅酸四乙酯(TEOS)为原料制备ZIF-8-SiO₂复合材料,并采用XRD、SEM、EDS等方法对ZIF-8-SiO₂的结构及吸附U(VI)前后的形貌进行表征,结果表明ZIF-8-SiO₂成功制备且对U(VI)具有良好的吸附作用。以静态吸附实验,分别考察了pH值、时间、温度、溶液初始铀浓度、盐浓度及超高压环境等对ZIF-8-SiO₂吸附性能的影响。由实验结果可得,在初始浓度为80 mg·L?1时,25℃下ZIF-8-SiO₂对U(VI)的最大实际吸附量为498 mg·g?1,根据Langmuir模型拟合结果分析得出,ZIF-8-SiO₂对U(VI)的理论吸附量最高可达678.5 mg·g?1,且在200~500 MPa范围内,压强越高越有利于吸附。通过FTIR、XPS等方法对ZIF-8-SiO₂吸附铀酰离子前后的结构进行分析,探究该吸附过程中可能存在的吸附机制。      

MOF原位生长改性聚对氯甲基苯乙烯-聚偏氟乙烯正渗透复合膜及其对乳化油废水的抗污染性

金属-有机框架(MOF)材料有望提高正渗透(FO)膜的水通量和抗污染性，以提高其对乳化油废水的分离性能。为将MOF引入FO膜，首先通过相转化法制备聚对氯甲基苯乙烯-聚偏氟乙烯(PCMS-PVDF)共混底膜，以底膜中的氯甲基基团(-CH₂Cl)为反应位点与2-甲基咪唑(Hmim)中的仲胺或叔胺反应，接着与硝酸锌(Zn(NO₃)₂)反应，以在膜表面原位生长金属有机骨架沸石咪唑酯骨架-8 (ZIF-8)，最后经界面聚合制备抗污染FO复合膜。通过SEM、XPS、FTIR和接触角测定仪等对底膜和FO膜的表面化学结构及膜亲/疏水性能等进行表征。结果表明：ZIF-8均匀生长在PCMS-PVDF底膜表面，且该纳米粒子为形状较规则的立方晶体。由于ZIF-8的存在使底膜表面较疏水，但界面聚合后形成的聚酰胺层重新使膜表面变为亲水。对膜的渗透分离和抗污染性研究表明，在FO模式下，以1 mol/L的NaCl为汲取液时，未经ZIF-8改性的FO膜(PCMS-PVDF-FO)水通量仅为12.4 L·m^-2·h^-1     

A Study on the Preparation and Anti-Tumor Efficacy of Bovine Serum Albumin Nanospheres Containing 5-Fluorouracil

ABSTRACT

The therapeutic profile of many anti-cancer drugs has been improved by their modified distribution through a colloidal carrier system. Hence, bovine serum albumin nanospheres containing 5-fluorouracil were prepared by pH-coacervation methods. To select the most suitable cryoprotector for the formulated nanosphere system, a study on the effect of cryoprotectors in the prevention of particle agglomeration was done. Using glucose and mannitol at various concentrations during freeze drying, glucose at a concentration of 5% was observed to be relatively more effective in the prevention of particle agglomeration than the other cryoprotectors. The carrier capacity was determined through the drug-to-albumin ratio. The particle size of all the drug-loaded batches was analyzed before and after freeze drying. The batch of nanospheres with uniform size distribution, and highest drug loading, was used for other subsequent studies. The effect of surfactant in drug loading was estimated through various concentrations of sodium lauryl sulfate, and it was observed that the surfactant has no influence on drug loading at the selected concentrations. The batch of nanospheres with highest drug loading was evaluated for its in-vitro release, and the drug release was found to be in a bi-phasic pattern. To evaluate the efficacy of 5-fluorouracil-loaded nanospheres against cancer cells, an in vitro cytotoxicity study was carried out using HEp-2 cell lines. The nanosphere-bound drug was observed to produce a better cytotoxic effect than the free drug. The anti-tumor efficacy of drug-loaded nanosphere was investigated in DLA tumor-induced mice models, and the percentage tumor inhibition was relatively higher in animals treated with nanosphere-bound drug than with free drug.     

A study on the preparation and anti-tumor efficacy of bovine serum albumin nanospheres containing 5-fluorouracil

The therapeutic profile of many anti-cancer drugs has been improved by their modified distribution through a colloidal carrier system. Hence, bovine serum albumin nanospheres containing 5-fluorouracil were prepared by pH-coacervation methods. To select the most suitable cryoprotector for the formulated nanosphere system, a study on the effect of cryoprotectors in the prevention of particle agglomeration was done. Using glucose and mannitol at various concentrations during freeze drying, glucose at a concentration of 5% was observed to be relatively more effective in the prevention of particle agglomeration than the other cryoprotectors. The carrier capacity was determined through the drug-to-albumin ratio. The particle size of all the drug-loaded batches was analyzed before and after freeze drying. The batch of nanospheres with uniform size distribution, and highest drug loading, was used for other subsequent studies. The effect of surfactant in drug loading was estimated through various concentrations of sodium lauryl sulfate, and it was observed that the surfactant has no influence on drug loading at the selected concentrations. The batch of nanospheres with highest drug loading was evaluated for its in-vitro release, and the drug release was found to be in a bi-phasic pattern. To evaluate the efficacy of 5-fluorouracil-loaded nanospheres against cancer cells, an in vitro cytotoxicity study was carried out using HEp-2 cell lines. The nanosphere-bound drug was observed to produce a better cytotoxic effect than the free drug. The anti-tumor efficacy of drug-loaded nanosphere was investigated in DLA tumor-induced mice models, and the percentage tumor inhibition was relatively higher in animals treated with nanosphere-bound drug than with free drug.     

Hybrid nanostructured drug carrier with tunable and controlled drug release

We describe here a transformative approach to synthesize a hybrid nanostructured drug carrier that exhibits the characteristics of controlled drug release. The synthesis of the nanohybrid architecture involved two steps. The first step involved direct crystallization of biocompatible copolymer along the long axis of the carbon nanotubes (CNTs), followed by the second step of attachment of drug molecule to the polymer via hydrogen bonding. The extraordinary inorganic–organic hybrid architecture exhibited high drug loading ability and is physically stable even under extreme conditions of acidic media and ultrasonic irradiation. The temperature and pH sensitive characteristics of the hybrid drug carrier and high drug loading ability merit its consideration as a promising carrier and utilization of the fundamental aspects used for synthesis of other promising drug carriers. The higher drug release response during the application of ultrasonic frequency is ascribed to a cavitation-type process in which the acoustic bubbles nucleate and collapse releasing the drug. Furthermore, the study underscores the potential of uniquely combining CNTs and biopolymers for drug delivery.     

Ibuprofen loaded porous calcium phosphate nanospheres for skeletal drug delivery system

Porous calcium phosphate nanospheres were successfully fabricated by a simple sonochemical method, and used as a drug carrier of ibuprofen. Morphology, structure, ibuprofen storage capacity, and release rate of the calcium phosphate nanospheres were characterized using FE-SEM, TEM, Nitrogen adsorption, XRD, FTIR, and UV–vis adsorption spectroscopies. Results showed the obtained calcium phosphate nanospheres held a porous structure with an average diameter of 48.9 ± 17.42 nm. Moreover, the porous nanospheres possessed an adjustable load amount and release rate for ibuprofen by changing drug concentrations during the drug loading process. In addition, the effects of size and dispersancy of porous spheres on drug release rate were discussed, which was found that larger or agglomerate porous spheres could delay drug release process. This study indicated that porous calcium phosphate nanospheres were a perfect drug carrier for ibuprofen, which has potential application for the therapy of skeletal disease.     

Regulation of particle morphology of pH-dependent poly(epsilon-caprolactone)-poly(gamma-glutamic acid) micellar nanoparticles to combat breast cancer cells

The advantage of polymeric drug carriers lies in the uptake of the polymer nanoparticles by cancer cells before they release the drug, thereby reducing its toxic effects on healthy cells. A poly(gamma-glutamic acid)-b-poly(epsilon-caprolactone)-b-poly(gamma-glutamic acid) block copolymer was synthesized to encapsulate the anti-cancer drug doxorubicin in the treatment of wild type human breast cancer cells (MCF-7/WT). This pH-controllable carrier is negatively-charged in the presence of healthy tissues leading to lower cellular uptake. On the other hand, it becomes more hydrophobic in the acidic environment of cancer tissues, increasing its cellular uptake through the lipid bilayer. The block copolymer was characterized using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry and dynamic light scattering. The micelles formed at a critical concentration range of 62-130 microg/mL depending on the composition of poly(gamma-glutamic acid) and poly(epsilon-caprolactone) chains. The nano-sized micelles were found to have pH-dependent sizes in the range of 90-200 nm. The role of poly(gamma-glutamic acid) was to increase the hydrophilicity and decrease the particle size of the copolymer. The structures of micelles that were more compact and less anionic showed better stability in plasma. It was found that the drug loading content and drug loading efficiency were 12.14% and 97.22% respectively. The copolymer showed shrinking and aggregation at low pH which led to a slower drug release. These nano-sized micelles showed potential as effective drug delivery carriers for doxorubicin because of its accumulation and slow release inside the MCF-7/WT cells.     

Tricalcium phosphate and tricalcium phosphate/polycaprolactone particulate composite for controlled release of protein

β-Tricalcium phosphate (β-TCP) with three different particle size ranges was used to study the effects of particle size and surface area on protein adsorption and release. Polycaprolactone (PCL) coating was applied on the particle systems to investigate its effect on particulate system properties from both structural and application aspects. The maximum loading of 27 mg/g was achieved for 100 nm particles. Bovine serum albumin (BSA) loading amount was controlled by varying the BSA loading solution concentration, as well as the sample powder's surface area. Increasing the surface area of the delivery powder significantly increased loading and release yield. Unlike the samples with low surface area, the lowest particle size samples showed sigmoidal release profile. This indicated that release was governed by different mechanisms for particles with different sizes. While the majority of samples showed no more than 50% release, the 550 nm particles demonstrated 100% release. PCL coating showed no significant ability to attenuate burst release in PBS. However, it led to a steadier release profile as compared to the bare TCP particles. FTIR analysis also proved that the secondary structure of BSA did not change significantly during the adsorption; however, minor denaturation was found during the release. The same results were found when PCL coating was applied on the TCP particles. We envision potential use of TCP and TCP + PCL systems in bone growth factor or orthopedic drug delivery applications in future bone tissue engineering application.     

纳米羟基磷灰石/聚酰胺66复合材料药物缓释载体研究

将纳米羟基磷灰石/聚酰胺66(n-HA/PA66)复合材料与抗生素类药物头孢哌酮钠(cefoperazone Sodium)复合,用特定溶剂将其调成糊状并自固化后,对该复合材料负载抗生素后的理化特性进行了研究.通过红外光谱及X射线衍射分析显示,载药材料保持了良好的化学稳定性.扫描电镜图象显示,材料表面及内部结构多孔.自固化n-HA/PA66复合材料在骨修复药物载体方面有很好的开发和应用前景.     

High drug loading polymer micelle@ZIF-8 hybrid core–shell nanoparticles through donor–receptor coordination interaction for pH/H2O2-responsive drug release

Smart drug delivery nanocarriers with high drug loading capacity are of great importance in the treatment of diseases, and can improve therapeutic effectiveness as well as alleviate side effects in patients. In this work, a pH and H₂O₂-responsive drug delivery platform with high doxorubicin (DOX) loading capacity has been established through coordination interaction between DOX and phenylboronic acid containing block polymer. A composited drug nanocarrier is further fabricated by growing a zeolitic imidazolate framework 8 (ZIF-8) on the surface of drug-loaded polymer micelles. The study verifies that ZIF-8 shell can act as intelligent “switch” to prevent DOX leaking from core–shell nanoparticles upon H₂O₂ stimulus. However, a burst drug release is detected upon pH and H₂O₂ stimuli due to the further disassociation of ZIF-8 in acid solution. Moreover, the in vitro anti-cancer experiments demonstrate that the DOX-loaded core–shell nanoparticles provide effective treatment towards cancer cells but have negligible effect on normal cells, which results from the high concentration of H₂O₂ and low pH in the microenvironment of tumor cells.     

金属有机框架固定化漆酶的制备及其对邻苯二酚的降解

以金属有机框架材料(ZIF-90)为固定载体,采用内部封装和表面物理吸附两种方法固定漆酶(LAC),分别制备出LAC@ZIF-90和LAC-ZIF-90复合材料,使用扫描电镜(SEM)、激光共聚焦显微镜(CLSM)、X射线衍射(XRD)、傅里叶红外变换光谱(FT-IR)以及荧光分析等手段分析漆酶固定前后的结构和性能,对比分析了游离漆酶和固定漆酶的使用稳定性,根据高效液相色谱(HPLC)研究了固定化漆酶对邻苯二酚的降解性能。结果表明：漆酶分子固定在ZIF-90的表面和内部,分子结构稳定。在最适当的pH值条件下,LAC-ZIF-90和LAC@ZIF-90震荡6 h对邻苯二酚的去除率分别为97%和19.4%。LAC-ZIF-90和LAC@ZIF-90经过5次重复使用后仍具有较高的活力,LAC-ZIF-90重复5次后对邻苯二酚的去除率仍高于78%。