透明质酸修饰的葛根素PEG-PLGA纳米粒的处方工艺优化及其体外评价

目的?以乳酸-羟基乙酸共聚物（PEG-PLGA）为载体,优化纳米沉淀法制备透明质酸修饰的葛根素PEG-PLGA纳米粒（HA/Pue-NPs）,并对其体外性质进行初步评价。方法?以PEG-PLGA为载体材料,透明质酸为表面修饰剂,采用纳米沉淀法制备了透明质酸修饰的HA/Pue-NPs;应用正交实验设计优化处方,对其体外性质进行表征;并采用体外释药行为评价透明质酸修饰HA/Pue-NPs。结果?制备出的载药纳米粒外观呈球形,平均粒径、Zeta电位分别为（88.9±2.2）nm、（-21.9±0.54）mV,载药量及包封率分别为6.75%、78.52%。体外释药试验表明,载药纳米粒释药缓慢,24h的累计释放率为65.8%。结论?透明质酸修饰的葛根素PEG-PLGA纳米粒粒径大小均一,体外性质良好且具有一定的缓释特性。      

5 nm金纳米颗粒对大鼠皮质神经元的作用及机制初探

目的:探讨直径5 nm的小尺寸金纳米颗粒(gold nanoparticles,GNPs)对大鼠皮质神经元细胞的作用及相关机制?方法:使用硼氢化钠还原法制备GNPs,用透射电镜(TEM)及紫外-可见光光谱(UV-Vis)进行鉴定?用5% 牛血清白蛋白(BSA)对GNPs进行包裹提纯后制备成不同浓度(600?1 200?2 400 μg/L)的GNPs培养液?采用免疫荧光染色鉴定原代培养的大鼠皮质神经元纯度?体外培养原代大鼠皮质神经元72 h后,以正常培养的神经元为对照组,以不同浓度GNPs溶液孵育48 h后的神经元作为实验组?采用TEM观察GNPs在细胞内的分布;采用CCK-8试剂盒检测细胞活力;采用TUNEL法检测细胞凋亡;采用丙二醛(MDA)?超氧化物歧化酶(SOD)试剂盒检测氧化应激水平?结果:TEM及UV-Vis显示硼氢化钠还原法制备的GNPs呈尺寸均一的球形,在溶液中均匀分散?原代培养的大鼠皮质神经元纯度为(82.0 ± 2.3)%?GNPs主要以聚合体形式分布于胞浆?溶酶体?囊泡中?随着GNPs浓度的增高,细胞活性逐渐降低,尤其1 200和2 400 μg/L处理组细胞活力较对照组显著降低(P < 0.05)?TUNEL染色结果显示,随着GNPs浓度的增高,凋亡细胞数逐渐增加,1 200和2 400 μg/L处理组细胞凋亡明显,具有显著性差异(P < 0.05)?随着GNPs浓度的增高,细胞内MDA含量逐渐增加,SOD含量逐渐减少,1 200和2 400 μg/L处理组与对照组相比MDA含量显著升高,SOD含量显著降低(P < 0.05)?结论:5 nm GNPs能降低大鼠皮质神经元的细胞活力,促进其凋亡,其机制可能与氧化应激损伤相关?     

聚乙烯亚胺修饰纳米金基因载体制备及体外实验研究

目的 制备聚乙烯亚胺修饰纳米金基因载体并研究其理化性质的表征参数和体外转染效率.方法 通过化学还原法制备聚乙烯亚胺修饰的纳米金基因载体,用绿色荧光蛋白质粒(pAcGFP-N1)做报告基因,纳米基因载体可通过静电吸附的方式结合质粒DNA.用紫外分光光度计检测其吸收光谱,用透射电镜观察其形态特征,激光粒度分析仪测定其粒度分布、表面电位(Zeta电位),1％琼脂糖凝胶电泳检测该基因载体与质粒DNA的结合稳定性,CCK-8实验检测聚乙烯亚胺修饰纳米金基因载体及DNA-纳米金复合物对HEK293细胞的细胞毒性作用,通过荧光显微镜观察聚乙烯亚胺纳米基因载体介导pAcGFP-N1在体外培养的HEK293细胞中的表达,并分析其转染效率.结果 聚乙烯亚胺还原氯金酸可以得到带正电荷的纳米颗粒,呈单分散球形分布,其粒径为(12.3 ±3.3)nm.在pH =7.2时,Zeta电位为+(29.7±5.1)mV.1％琼脂糖凝胶电泳结果表明,当纳米金/质粒DNA≥0.5时,质粒DNA可完全结合到纳米金表面.体外转染实验表明,聚乙烯亚胺修饰纳米金基因载体能介导pAcGFP-N1转染HEK293细胞并在细胞中表达绿色荧光蛋白,其转染效率可达25％.结论 聚乙烯亚胺修饰纳米金是一种新型非病毒基因载体,具有转染效率高、对细胞毒性小等优势.     

Intracellular target delivery of 10-hydroxycamptothecin with solid lipid nanoparticles against multidrug resistance

The main objective of this study was to design a suitable drug delivery system for 10-hydroxycamptothecin (HCPT). In this study, HCPT-loaded solid lipid nanoparticle (HCPT-loaded SLN) was successfully prepared. The HCPT-loaded SLN was characterized by size, entrapment efficiency and drug release manner. The cytotoxicity of HCPT-loaded SLN was assessed in vitro using HepG2/HCPT cells and in vivo utilizing human tumor xenograft nude mouse model. HCPT-loaded SLN indicated the ability to target HepG2/HCPT cells and accumulated higher drug content in HepG2/HCPT cells. HCPT-loaded SLN enhanced the cytotoxicity of HCPT in a concentration-dependent manner. Based on these results, HCPT-loaded SLN suggested being a promising vehicle for liver-targeted drug delivery. Moreover, it can be of clinical interest to overcome multidrug resistance (MDR) effectively.     

Antibacterial‐nanocomposite bone filler based on silver nanoparticles and polysaccharides

Injectable bone fillers represent an attractive strategy for the treatment of bone defects. These injectable materials should be biocompatible, capable of supporting cell growth and possibly able to exert antibacterial effects. In this work, nanocomposite microbeads based on alginate, chitlac, hydroxyapatite and silver nanoparticles were prepared and characterized. The dried microbeads displayed a rapid swelling in contact with simulated body fluid and maintained their integrity for more than 30 days. The evaluation of silver leakage from the microbeads showed that the antibacterial metal is slowly released in saline solution, with less than 6% of silver released after 1 week. Antibacterial tests proved that the microbeads displayed bactericidal effects toward Staphylococcus aureus, Pseudomonas aeruginosa and Staphylococcus epidermidis, and were also able to damage pre‐formed bacterial biofilms. On the other hand, the microbeads did not exert any cytotoxic effect towards osteoblast‐like cells. After characterization of the microbeads bioactivity, a possible means to embed them in a fluid medium was explored in order to obtain an injectable paste. Upon suspension of the particles in alginate solution or alginate/hyaluronic acid mixtures, a homogenous and time‐stable paste was obtained. Mechanical tests enabled to quantify the extrusion forces from surgical syringes, pointing out the proper injectability of the material. This novel antibacterial bone filler appears as a promising material for the treatment of bone defects, in particular when possible infections could compromise the bone‐healing process. Copyright © 2016 John Wiley & Sons, Ltd.     

A magnetic ion-imprinted polymer for lead(II) determination: A study on the adsorption of lead(II) by beverages

In this work a variety of beverage samples had been kept in a contaminated area to investigate their lead adsorption. To determine the adsorbed Pb(II), a novel magnetic lead ion-imprinted polymer, grafted onto Fe₃O₄ nanoparticles, was synthesized and used as a selective sorbent for the preconcentration of Pb(II) ions. The sorbent was characterized by different techniques. The synthesized sorbent was applied for highly accurate and selective determination of Pb(II) ions absorbed from polluted air in several beverages and results were compared. To validate the method, three certified reference materials were analyzed by the proposed method and the results showed that pre-concentrating by this sorbent and subsequent determination by flame atomic absorption spectroscopy is an accurate method for lead determination in beverage samples (recoveries higher than 95%). The limits of detection and the relative standard deviations were less than 1.7 μg kg⁻¹ and 4.1%, respectively. The sorption capacity of this new sorbent was 51.8 mg g⁻¹. Finally, this method was used for the determination of Pb(II) ions in polluted beverage samples, and the results revealed that under equal conditions, coffee exhibits more tendency to adsorb Pb(II) ions.     

Potential of biofluid components to modify silver nanoparticle toxicity

Establishing realistic exposure scenarios is critical for cytotoxic investigation of silver nanoparticles (AgNP) in the gastrointestinal tract. This study investigated the potential interaction with and effect of biofluid components, namely cholic acid, deoxycholic acid and ursodeoxycholic acid, on AgNP toxicity. Two cell lines corresponding to organs related to the biofluid components were employed. These were HepG‐2 a hepatocellular carcinoma derived from liver tissue and Hep2 an epithelial cell line. Physiochemical and cytotoxic screening was performed and the ability of biofluid components to modify AgNP cytotoxicity was explored. No alteration to the physiochemical characteristics of AgNP by biofluid components was demonstrated. However, biofluid component addition resulted in alteration of AgNP toxicity. Greater reactive oxygen species induction was noted in the presence of cholic acid and deoxycholic acid. Ursodeoxycholic acid demonstrated no modification of toxicity in HepG‐2 cells; however, significant modification was noted in Hep2 cells. It is concluded that biofluid components can modify AgNP toxicity but this is dependent on the biofluid component itself and the location where it acts. Copyright © 2015 John Wiley & Sons, Ltd.