半乳糖基壳聚糖5氟尿嘧啶纳米粒的制备及其抑制小鼠结肠癌的实验研究

目的:半乳糖基壳聚糖纳米材料与5-氟尿嘧啶(5-FU)合成5-FU纳米粒,并观察其在体内抑制小鼠结肠癌的疗效.方法:将体外培养的C26细胞接种小鼠肝左叶,成瘤后,分别用0.9％氯化钠液、空纳米粒、5-FU和5-FU纳米粒行尾静脉注射,观察5-FU纳米粒的抗肿瘤效果.用酶联免疫吸附试验法检测血清γ干扰素(IFN-γ)和白细胞介素-2(IL-2)含量,用四甲基偶氮唑盐(MTT)比色法测定小鼠脾自然杀伤细胞(NK细胞)和细胞毒性T细胞(CTL细胞)活性.结果:与0.9％氯化钠液组及纳米粒组相比,5-FU组和5-FU纳米粒组的瘤质量显著降低(P＜0.01),尤其5-FU纳米粒组降低更显著(P＜0.01).与其他各组比较,5-FU组小鼠,外周血IFN-γ和IL-2含量均显著降低(P＜0.01),5-FU纳米粒组与0.9％氯化钠液组比较差异无统计学意义(P＞0.05).5-FU组的脾NK细胞和CTL细胞杀伤活性较其他各组显著降低(P＜0.01),5-FU纳米粒组与0.9％氯化钠液组比较未见降低(P＞0.05),纳米粒组NK和CTL杀伤活性0.9％氯化钠液组增高(P＜0.05).结论:5-FU纳米粒治疗结肠癌模型,具有明显抗肿瘤效应,纳米粒材料具有提高机体免疫功能,减低5-FU对机体免疫的抑制作用.     

Natural steroid-based cationic copolymers cholesterol/diosgenin-r-PDMAEMAs and their pDNA nanoplexes: impact of steroid structures and hydrophobic/hydrophilic ratios on pDNA delivery

Using natural-based lipids to construct biocompatible, controllable and efficient nanocarriers and elucidating their structure–function relationships, was regarded as an important area for creating sustainable biomaterials. Herein, we utilized two natural steroids: cholesterol and diosgenin (bearing different hydrophobic tails) as the building blocks, to synthesize a series of natural steroid-based cationic random copolymers PMA6Chol-r-PDMAEMA and PMA6Dios-r-PDMAEMA via RAFT polymerization. The results demonstrated that the steroid-r-PDMAEMA copolymers could efficiently bind pDNA (N/P < 3.0) and then form near-spherical shape (142–449 nm) and positively-charged (+11.5 to +19.6 mV) nanoparticles. The in vitro cytotoxicity and gene transfection efficiency greatly depend on the steroid hydrophobic tail structures and steroid/PDMAEMA block ratios. Optimum transfection efficiency of the (Chol-P1/pDNA and Dios-P3/pDNA) nanoplexes could reach to 18.1–31.2% of the PEI-25K/pDNA complex. Moreover, all of the steroid-r-PDMAEMA/Cy3-pDNA nanoplexes have an obvious “lysosome localization” effect, indicating the steroid structures do not remarkably influence the intracellular localization behaviors of these nanoplexes.

Using natural-based lipids to construct biocompatible, controllable and efficient nanocarriers and elucidating their structure–function relationships, was regarded as an important area for creating sustainable biomaterials.     

聚乳酸-O-羧甲基壳聚糖纳米粒子培养的猪肝细胞移植对大鼠急性肝衰竭的治疗作用

目的:探讨胶原凝胶包埋的聚乳酸-O-羧甲基壳聚糖纳米粒子培养的猪肝细胞腹腔内移植对急性肝衰竭(ALF)大鼠的治疗效果。方法:D-氨基半乳糖腹腔内注射制作大鼠ALF模型。48h后分别将培养24h的猪肝细胞悬液(含5.0×107个肝细胞,Ⅰ组)、Ⅰ型胶原凝胶固定培养24h的猪肝细胞(含5.0×107个肝细胞,Ⅱ组)、Ⅰ型胶原凝胶包埋的PLA-O-CMC纳米粒子培养24h的猪肝细胞(含5.0×107个肝细胞,Ⅲ组)移植到ALF大鼠腹腔内,并以RPMI1640腹腔内注射作为对照(Ⅳ组)。观察移植后大鼠14d存活率,血清白蛋白(ALB)、谷丙转氨酶(ALT)、总胆红素(TB)、血氨(NH3)的变化和移植肝细胞的病理变化。结果:移植后14d ALF大鼠的存活率:Ⅰ组为56.25%,Ⅱ组为62.5%,Ⅲ组为75%,Ⅳ组为18.75%,各移植组高于对照组(P<0.05)。移植后1~5d,Ⅰ、Ⅱ、Ⅲ组各项肝功能指标改善明显优于Ⅳ组,Ⅲ组肝功能恢复好于同时间其它移植组,肝功能恢复从快到慢依次为Ⅲ、Ⅱ、Ⅰ、Ⅳ组。Ⅲ组移植肝细胞存活时间最长,炎症浸润最轻。结论:应用胶原凝胶包埋的聚乳酸-O-羧甲基壳聚糖纳米粒子培养的猪肝细胞腹腔内移植治疗ALF大鼠能显著改善肝功能、提高生存率,聚乳酸-O-羧甲基壳聚糖纳米粒子用于异种肝细胞移植具有良好的生物相容性,并能延长移植肝细胞的存活时间。     

Biosynthesis of Gold Nanoparticles Using Bacteria

Biosynthesis of gold nanoparticles (AuNPs) from Pseudomonas aeruginosa and Rhodopseudomonas capsulata bacteria is considered to be a novel, effective and eco-friendly method. The important parameter, which controls the size and shape of AuNPs, was pH value. The R. capsulata biomass and aqueous HAuCl₄ solution were incubated at pH values ranging from 7 to 4. The AuNPs were characterized by UV–Vis whose absorbance measured at 540 nm followed by transmission electron microscopy showed the formation of AuNPs in the range of 20–80 nm in diameter at pH 6.5. Scanning electron microscopy revealed the AuNPs ranging from 50 to 70 nm, Fourier transform infrared spectroscopy confirmed the formation of AuNPs in the range of 4,000–400 cm^?1. The results demonstrated that spherical AuNPs in the range of 10–20 nm were observed at pH value of 7 whereas a number of nanoplates were observed at pH 4. Hence, the present study enlightens on the green chemistry approach on the production of AuNPs using microorganisms. In comparison to chemical synthesis, the synthesis of AuNPs by microbial source is the most reliable method of production and yield.     

Probing In Vivo Trafficking of Polymer/DNA Micellar Nanoparticles Using SPECT/CT Imaging

Successful translation of nonviral gene delivery to therapeutic applications requires detailed understanding of in vivo trafficking of the vehicles. This report compares the pharmacokinetic and biodistribution profiles of polyethylene glycol-b-polyphosphoramidate (PEG-b-PPA)/DNA micellar nanoparticles after administration through intravenous infusion, intrabiliary infusion, and hydrodynamic injection using single photon emission computed tomography/computed tomography (SPECT/CT) imaging. Nanoparticles were labeled with ¹¹¹In using an optimized protocol to retain their favorable physicochemical properties. Quantitative imaging analysis revealed different in vivo trafficking kinetics for PEG-b-PPA/DNA nanoparticles after different routes of administration. The intrabiliary infusion resulted in the highest liver uptake of micelles compared with the other two routes. Analysis of intrabiliary infusion by the two-compartment pharmacokinetic modeling revealed efficient retention of micelles in the liver and minimal micelle leakage from the liver to the blood stream. This study demonstrates the utility of SPECT/CT as an effective noninvasive imaging modality for the characterization of nanoparticle trafficking in vivo and confirms that intrabiliary infusion is an effective route for liver-targeted delivery of DNA-containing nanoparticles.     

Delivery and expression of pDNA embedded in collagen matrices.

Collagen matrices can be used as non-viral biocompatible gene carriers for localized implantable gene therapy. Collagen matrices embedding pDNA with enhanced binding through condensing agent linkage to the matrix or to the pDNA have been formulated, and characterized in various systems. pDNA and condensed pDNA were released intact from the matrices within 1-2 days. In vitro transfection with collagen matrices containing pDNA (luciferase encoding), pDNA in liposome (LIP), and pDNA with polyethylenimine (PEI) resulted in significantly higher expression levels in comparison to naked pDNA. pDNA-LIP matrices exhibited a dose response transfection of NIH 3T3, 293, MDA-MB-231 and smooth muscle cells (SMCs) in cell cultures. Subdermal implantations of collagen-polylysine-pDNA matrices in rats resulted in significantly higher gene expression levels in comparison to non-condensed pDNA matrices. Perivascular treatment with pDNA matrix and of naked pDNA solution in balloon-injured rat carotid arteries resulted in significant expression. In conclusion, a facile method for embedding cationic formulations of pDNA in collagen matrices was developed. These bioactive matrices seem to be suitable for tissue engineering and local gene therapy strategies.     

Assembly of Therapeutic pRNA-siRNA Nanoparticles Using Bipartite Approach

The 117-nucleotide (nt) RNA, called the packaging RNA (pRNA) of bacteriophage phi29 DNA packaging motor, has been shown to be an efficient vector for the construction of RNA nanoparticles for the delivery of small interfering RNA (siRNA) into specific cancer or viral-infected cells. Currently, chemical synthesis of 117-nt RNA is not feasible commercially. In addition, labeling at specific locations on pRNA requires the understanding of its modular organization. Here, we report multiple approaches for the construction of a functional 117-base pRNA using two synthetic RNA fragments with variable modifications. The resulting bipartite pRNA was fully competent in associating with other interacting pRNAs to form dimers, as demonstrated by the packaging of DNA via the nanomotor and the assembly of phi29 viruses in vitro. The pRNA subunit assembled from bipartite fragments harboring siRNA or receptor-binding ligands were equally competent in assembling into dimers. The subunits carrying different functionalities were able to bind cancer cells specifically, enter the cell, and silence specific genes of interest. The pRNA nanoparticles were subsequently processed by Dicer to release the siRNA embedded within the nanoparticles. The results will pave the way toward the treatment of diseases using synthetic pRNA/siRNA chimeric nanoparticles.     

脂质微泡-载紫杉醇纳米粒包裹紫杉醇的肝素纳米粒与脂质微泡复合物的制备

目的 制备一种新型包裹紫杉醇的肝素纳米粒-微泡复合物,并对其理化性质进行检测.方法 以肝素为原料制备生物素化包裹紫杉醇的肝素纳米粒,动态光散射仪测定其粒径及电位,透射电镜观察其形态,紫外分光光度计测定载药量.采用机械震荡法制备生物素化脂质微泡.借助生物素-亲和素桥接作用将两者偶联,制备复合物体系,激光共聚焦显微镜观察Oregon green绿色荧光标记的载药纳米粒与DiI红色荧光标记的脂质微泡的连接效果,用库尔特粒度分析仪进行粒度分析.结果 肝素纳米粒的粒径为120 nm,电位为-35 mV,电镜观察呈球形,大小均匀,分散度好,载药量为8.84％.激光共聚焦显微镜观察肝素纳米粒成功连接在微泡表面.库尔特粒度分析仪测定微泡粒径为(2.20±0.93)μm,浓度为(11.31±1.0)×108个/ml,复合物的粒径为(2.26±0.86) μm,浓度为(7.78±1.2)×108个/ml.结论 成功制备具有较好药物运载性能的新型载紫杉醇肝素纳米粒-微泡复合物.     

中等粒径葡聚糖超顺磁性氧化铁纳米颗粒的制备

目的制备中等粒径葡聚糖超顺磁性氧化铁纳米颗粒，评估其作为一种新型的磁共振对比剂可行性。方法采用化学共沉淀法制作葡聚糖超顺磁性氧化铁纳米颗粒，通过凝胶色谱分离葡聚糖超顺磁性氧化铁纳米颗粒，用透射电子显微镜、粒度分析仪、X射线衍射和磁力计对葡聚糖超顺磁性氧化铁纳米颗粒进行表征分析。结果粒度分析仪与电子显微镜检测结果表明，目的粒子均匀一致，葡聚糖超顺磁性氧化铁纳米颗粒核心直径在35—41nm之间，平均粒径40nm。磁力仪检测结果显示，磁化曲线无磁滞现象，表现为超顺磁性，矫顽力为零，饱和磁化强度为23KA／m。结论实验结果表明，所制备的中等粒径聚糖超顺磁性氧化铁纳米可作为一种新型的磁共振造影对比剂，广泛应用于多种疾病的临床诊断和治疗。     

高温乳化-低温固化法制备芦丁固体脂质纳米粒及理化性质分析

目的观察高温乳化-低温固化法制备的芦丁固体脂质纳米粒（RT-SLN）的理化性质及体外释药特性。方法以硬脂酸为脂质材料,采用高温乳化-低温固化法制备芦丁固体脂质纳米粒,以均匀设计法优化处方及制备工艺,并对其形态、粒径、Zeta电位、包封率（EE）、体外释药特征等进行评价。结果所制备的RT-SLN外观呈类球形,粒径为（192.47&#177;31.8）nm,Zeta电位（-18.90&#177;0.27）mV。以EE为评价指标表进行处方筛选,回归方程计算得优化工艺为药物-硬脂酸比1∶4,硬脂酸用量200mg,聚山梨酯-80浓度12mg/ml,聚乙二醇-400浓度5%、转速1500r/min,初乳与分散相体积比为1∶7,预测优化值为90.11%,其95%的可信区间为83.71%～96.51%,平均EE（89.34&#177;0.93）%。72h药物累积释放约85%,体外释药符合Higuchi方程：Q=8.345t1/2＋15.023（r=0.9892）。结论高温乳化-低温固化法适于制备RT-SLN,制备的RT-SLN具有缓释作用,能提供平稳的血药浓度,利于提高患者的用药依从性。     

载三氧化二砷壳聚糖微球的制备、表征及释药性能

目的:探讨载三氧化二砷(arsenic trioxide,As2O3)壳聚糖微球的制备工艺,并观察其表征和体外药物释放效果。方法:以三聚磷酸钠混合丙酮为凝胶浴,采用静电液滴法制备载As2O3壳聚糖微球。光镜和电镜下观察所得载药微球的成球效果,并进行粒径分析、红外光谱(Fourier transform infrared,FT-IR)和X-射线衍射分析。另将载As2O3壳聚糖微球置于模拟体液中,定时提取样本液,采用原子荧光法检测砷的释放量,从而评价载药微球的药物释放效果。结果:载As2O3壳聚糖微球外观圆整、均匀度好、颗粒形状规则无粘连,具有良好的分散性。这种载药微球的粒径为(239.5±11.2)μm,包封率为(87.3±6.5)%。FT-IR和X-射线衍射分析都表明三聚磷酸钠在微球制备中起到了较好的离子交联作用,能降低壳聚糖的结晶度,提高其水溶性。在最初4 h内载药微球的药物释放迅速,之后则平缓上升,24 h内药物释放量仅为(30.8±0.5)%。结论:采用静电液滴法制备载As2O3壳聚糖微球,工艺简单可靠,所得载药微球水溶性较好,表征较为满意,包封率高,药物释放较为平缓,在载药骨修复材料的研究中具有潜在的优势。     

5-氟脲嘧啶壳聚糖缓释微球的制备及其体外药物缓释性观察

目的制备5-氟脲嘧啶壳聚糖缓释微球并观察其体外缓释药物的作用。方法采用乳化-化学交联法制备5-氟脲嘧啶壳聚糖缓释微球,观察该微球的形态、粒径、药物包封率和在体外药物缓释作用。结果5-氟脲嘧啶壳聚糖缓释微球的平均粒径为（185.5±15.0）nm,包封率为（49.3±2.1）%,在pH7.4PBS缓冲溶液中对5-氟脲嘧啶的累计释放率第1天为（61.6±1.8）%,第3天为（78.2±1.6）%,第7天为（90.5±1.4）%。结论所制备的5-氟脲嘧啶壳聚糖缓释微球具有良好的药物包封率和体外释放作用,符合缓释药物的制备要求。     

Chitosan nanocomposites with CdSe/ZnS quantum dots and porphyrin

Water-soluble nanocomposites based on CdSe/ZnS quantum dots (QDs) and hydrophobic tetraphenylporphyrin (TPP) molecules passivated by chitosan (CS) have been formed. Magnetic circular dichroism (MCD) spectra evidence TPP presence in both monomeric and agglomerated forms in the nanocomposites. The nanocomposites demonstrate more pronounced singlet oxygen generation compared to free TPP in CS at the same concentration due to the intracomplex Förster resonance energy transfer (FRET) with a 45% average efficiency.

A CdSe/ZnS QD-TPP nanocomposite and energy transfer from QDs to (i) TPP monomers to oxygen generating singlet oxygen (SO) and (ii) TPP aggregates cannot generate SO in chitosan solution.     

Binding and uptake of cationic lipid:pDNA complexes by polarized airway epithelial cells

To better understand the barriers associated with cationic lipid-mediated gene transfer to polarized epithelial cells, Fischer rat thyroid (FRT) cells and polarized normal human bronchial epithelial (NHBE) cells grown on filter supports at an air-liquid interface were used to study the binding and uptake of cationic lipid:plasmid DNA (pDNA) complexes. The efficiencies of binding and uptake of cationic lipid:pDNA complexes by these cell systems were monitored using fluorescence microscopy of fluorescently tagged lipid or pDNA probes. Fluorescent probe bound to the cell surface was differentiated from internalized probe by adding trypan blue, which quenched the fluorescence of bound but not internalized probes. For proliferating cells, binding and internalization of the cationic lipid:pDNA complexes were determined to be efficient. In contrast, little binding or internalization of the complexes was observed using polarized epithelial cells. However, after aspirating a small area of cells from the filter support, virtually all of the cells adjoining this newly formed edge bound and internalized the cationic lipid:pDNA complexes. To determine if their uptake in edge cells was related to the ability of the complexes to access the basolateral membranes of these cells, the binding and uptake of complexes was monitored in polarized NHBE cells that had been pretreated with EGTA or Ca2+-free media, strategies known to disrupt tight junctions. Cells treated in this manner bound and internalized cationic lipid:pDNA complexes efficiently and also expressed significant levels of transgene product. Control cells with intact tight junctions neither bound complexes nor expressed significant transgene product. These data confirm and extend earlier observations that the polarized apical membranes of airway epithelial cells are resistant to transfection by lipid:pDNA complexes. Further, in contrast to previous studies that have shown the entry step of complexes is not an important barrier for COS and HeLa cells, binding and entry of complexes in polarized NHBE cells appear to be rate limiting. These findings suggest that strategies designed to open the tight junctions of polarized epithelial cells may improve gene delivery to these cells for diseases such as cystic fibrosis (CF).     

Rapid Detection of Staphylococcus aureus Genomic DNA Using Peptide Nucleic Acid and Gold Nanoparticles

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Staphylococcus aureus is a Gram-positive bacterium and is known to affect almost all mammalian species. This...     

Sunlight Irradiation Induced Green Synthesis of Stable Silver Nanoparticles Using Citrus limon Extract

In the present study, silver nanoparticles were rapidly synthesized photochemically by treating silver ions with lemon (Citrus limon) extract utilizing solar radiation. The effect of time period of the day on reaction rate and nanoparticle formation was investigated in details. In the standardized process, 10^?2 M silver nitrate solution was interacted for 20 min with lemon juice (2 % citric acid and 0.5 % ascorbic acid concentration) in the ratio of 1:4 (vol:vol) in the presence of sunlight. Silver nanoparticles below 50 nm with spherical and spheroidal shape were observed under electron microscopic analysis. The authors have hereby developed an energy efficient bio-based synthesis process which produces silver nanoparticles rapidly.