壳聚糖纳米粒的制备及体外抗幽门螺杆菌效果评价◆

背景：壳聚糖是甲壳素的脱乙酰产物，这种碱性氨基多糖具有天然抗菌活性，且抗菌广谱，但将其纳米化后抗幽门螺杆菌作用的报道较少。 目的：制备壳聚糖纳米粒并评价其体外抗幽门螺杆菌的疗效。 设计、时间及地点：体外对比观察实验，于2008-03/10在中南大学湘雅医院卫生部纳米生物技术重点实验室完成。 材料：采用聚合物分散法用脱乙酰度分别为88.5%和95%的2种壳聚糖粉末制备壳聚糖纳米粒。 方法：取0.5 mL含幽门螺杆菌(NCTC11639和NCTC11637)5×108 CFU/mL的布氏肉汤菌液均匀涂布于培养基上待干燥后，采用打孔法检验不同质量浓度(5，10，15，20 g/L)，不同pH值(pH=6,5,4)和不同脱乙酰度(88.5%和95%)壳聚糖纳米粒溶液的抑菌效果。 主要观察指标：抑菌环直径。抑菌环直径越大，说明该菌对此药敏感性越大，抗菌效果越好；反之越小，抗菌效果越差；若无抑菌环，则说明该菌对此药具有耐药性。 结果：pH值在4~6时，壳聚糖纳米粒的抑菌作用与pH值呈负相关(P < 0.01)，且在pH值为4时的抑菌效果最强。2种不同脱乙酰度壳聚糖对幽门螺杆菌的抑菌作用差异有显著性意义(P < 0.05)，壳聚糖纳米粒(脱乙酰度95%)的抑菌效果优于壳聚糖纳米粒(脱乙酰度88.5%)，在质量浓度处于5~20 g/L时抗幽门螺杆菌的作用差异无显著性意义(P > 0.05)。 结论：壳聚糖纳米粒提高了在体外对幽门螺杆菌的抑菌作用，且此作用在酸性条件下明显增强。用脱乙酰度为95%的壳聚糖粉末制备的壳聚糖纳米粒具有更好的抑幽门螺杆菌的作用。

Chitosan nanoparticle preparation and its anti-Helicobacter pylori efficacy in vitro

BACKGROUND: Chitosan (CS), an amino polysaccharide, is deacetylated from chitin, which has natural substances with antibiotic activity and wide antibacterial spectra. However, the effect of nano structured chitosan on anti-Helicobacter pylori (HP) is poorly understood. OBJECTIVE: To formulate and systematically evaluate anti-Hp efficacy of CS nanoparticles (NPs) in vitro. DESIGN, TIME AND SETTING: The in vitro control experiment was performed at the National Key Laboratory of Nanobiological Technology, Xiangya Hospital, Central South University from March to October 2008. MATERIALS: CS NPs were prepared by the polymerid dispersion method with 88.5% and 95% deacetylation. METHODS: Totally 0.5 mL Brucella Broth containing NCTC11639 and NCTC11637 5×108 CFU/mL were spread on culture medium. The anti-Hp effect of different concentration (5, 10, 15, 20 g/L) in vitro, different PH value (pH=6, 5, 4) and different deacetylation degree (88.5% and 95%) of CS NPs solution was detected with punch method. MAIN OUTCOME MEASURES: The diameter of inhibition zone, which demonstrated the antibacterial effect. No antimicrobial ring illustrates that the bacterium has drug resistance. RESULTS: At pH value 4-6, the anti-Hp effect of CS NPs solution had a negative correlation with pH value (P < 0.01), and the optimal pH value was 4. There were significant differences in anti-Hp effect between 88.5% deacelytation degree CS NPs and 95% deacelytation degree CS NPs (P < 0.05), which was superior in 95% deacelytation degree CS NPs, however, the anti-Hp effect of showed no difference within 5-20 g/L (P > 0.05). CONCLUSION: CS NPs improves the anti-Hp efficacy of CS in vitro and has the potential to kill Hp directly, and the action is strengthened in acid condition. 95% deacelytation degree CS can enhance the bacteriostatic activity of the chitosan nanoparticles.