Polypyrrole Chitosan Cobalt Ferrite Nanoparticles Composite Layer for Measuring the Low Concentration of Fluorene Using Surface Plasmon Resonance

Fluorene is a polycyclic aromatic hydrocarbon, which is a hazardous toxic chemical in the environment. The measurement of low concentrations of fluorene is a subject of intense interest in chemistry and in the environment. Polypyrrole chitosan cobalt ferrite nanoparticles are prepared using the electrochemical method. The prepared layers are characterized using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The layers are used to detect fluorene using the surface plasmon resonance technique at room temperature. The composite layer is evaluated after detection of fluorene using atomic force microscopy. The fluorene is bound on the layer, and the shift of the resonance angle is about 0.0052°, corresponding to the limitation of 0.01 ppm.

Does Chitosan Extend the Shelf Life of Fruits?

The use of hazardous formalin in increasing shelf life of fruits and protecting them from microbial decay by unscrupulous traders is a big health concern for the consumers in Bangladesh. Chitosan is a natural biopolymer produced from the exoskeletons of shrimp and crab, which slows antimicrobial activities and induces immunity of plants against microbial pests. This study aimed to evaluate the efficacy of chitosan on the shelf life extension of some local ripened fruits compared to untreated control. Three doses of chitosan solution viz. 0, 500 and 1000 ppm were sprayed in alternate day on banana (cvs. Shabri and Champa), strawberry, tomato, and oranges. It revealed that chitosan extended shelf life of all fruits by delaying the decay;however, level of protection varied in different kinds of fruits as well as in doses of the chitosan used. Among the tested fruits, decay of tomatoes was most delayed by chitosan. Spraying of both 500 and 1000 ppm of chitosan equally protected 100% decay in tomatoes until 8 days of treatments at room temperature. More than 80% protection of other fruits viz. banana, orange and strawberries by chitosan were recorded at 8, 8 and 4 day after treatment, respectively, which were remarkably higher than the untreated control. Interestingly, 500 ppm of chitosan spray gave better protection than 1000 ppm in all the tested fruits. These results suggest that lower doses of chitosan can be utilized as a natural preservative of fruits alternative to hazardous formalin. A further study with higher number of fruits, and at varying temperature and chitosan doses are needed for recommending it for practical application as a fruit preservative.

C-Fe@CN-CN对人肝癌细胞增殖的抑制作用

目的制备卡铂碳包铁纳米笼壳聚糖微球(C-Fe@CN-CN),观察其对人肝癌细胞体外增殖的抑制作用。方法采用反相微乳法制备C-Fe@CN-CN,测定其表征,观察其体外释药行为。采用MTT法检测C-Fe@CN-CN对人肝癌细胞体外增殖的抑制效应;计算IC50,绘制生长曲线。结果C-Fe@CN-CN球形圆整,平均粒径(2 0 7±2 1)nm,载药量为(1 1.4 0±1.3 1)%。C-Fe@CN-CN的体外释药行为包括快速相和平稳相两阶段,可持续5 d。C-Fe@CN-CN对人肝癌细胞增殖有明显抑制作用,并呈剂量和时间依赖性,作用2 4 h时抑制效应低于原药,作用4 8 h和7 2 h时抑制效应等同于原药。C-Fe@CN-CN的2 4,4 8,7 2 h IC50分别为1 3 5,1 8.8 4,6.0 9μg/mL。空白微球对肝癌细胞增殖无影响。结论C-Fe@CN-CN具有长循环和肿瘤组织滞留潜能,磁靶向性强,可缓释药物。体外能有效地抑制肝癌细胞增殖,空白微球表现出良好的生物相容性。

几丁糖对大鼠术后腹腔粘连的预防作用

目的 探讨几丁糖对术后腹腔粘连的预防作用。方法 将 45只大鼠随机分为对照组 (A组 ) ,右旋糖酐组 (B组 ) ,几丁糖组 (C组 ) ,于腹腔内浆膜损伤部位分别注入 1%乳酸液 ,3 2 %右旋糖酐 -70液 ,2 %几丁糖乳酸液各 2ml ,术后 14d处死动物 ,观察各组腹腔粘连状况并送病理检查。结果 3组粘连分级有显著性差异 (P <0 .0 1) ;C组粘连发生率较另 2组为低 ,有显著性差异 (P <0 .0 5 )。光镜下C组炎症反应轻微 ,纤维增生不明显 ;电镜下C组纤维细胞分泌胶原能力弱 ,间皮细胞增生活跃。结论 几丁糖可有效地降低大鼠术后腹腔粘连的发生和粘连程度 ,其作用优于右旋糖酐 -70 ,且不影响切口的愈合。