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化学学报
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化学学报 ›› 2013, Vol. 71 ›› Issue (12): 1656-1662.DOI: 10.6023/A13070720 上一篇    下一篇

研究论文

微量热法和荧光显微法研究CdTe量子点敏化的纳米TiO2对大肠杆菌的抗菌活性及细胞损伤机制

李月生, 李奔强, 孙绍发   

  1. 湖北科技学院非动力核技术湖北省协同创新中心 咸宁 437100
  • 投稿日期:2013-07-10 发布日期:2013-09-22
  • 通讯作者: 李月生 E-mail:frank78929@163
  • 基金资助:

    项目受国家科技部973计划（No. 2009CB939705）、国家级大学生创业训练和创业实践项目（Nos. 201210927033，201310927023）.

Microcalorimetric and Microscopic Studies on the Antibacterial Activities of CdTe(QDs)/TiO2 Nanocomposites and the Mechanism of Cell Damage on Escherichia coli

Li Yuesheng, Li Benqiang, Sun Shaofa   

  1. Non-power Nuclear Technology Collaborative Innovation Center, Hubei University of Science & Technology, Xianning 437100
  • Received:2013-07-10 Published:2013-09-22
  • Supported by:

    Project supported by the 973 program from Chinese Ministry of Science and Technology (No. 2009CB939705), the National University Students Training and Entrepreneurial Practice Project (No. 201210927033, 201310927023).

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通过水热合成法和自组装方法分别合成了CdTe(QDs)量子点与CdTe(QDs)敏化的纳米TiO2复合物，并将CdTe(QDs)/TiO2与TiO2均配成浓度为1×10-2 mol/L的悬浮液. 取一小环大肠杆菌(E. coli)的营养肉汤培养基至5 mL LB培养基中，则E. coli的浓度配成大约1×106 cell/mL的悬浮液以作备用. 在37.0 ℃条件下，利用LKB-2277生物活性检测仪并采用停流法进行检测，研究了CdTe(QDs)/TiO2对E. coli的抗菌行为. 通过测定和分析产热功率-时间曲线，获得细胞生长速率常数(k)、最大产热功率(Pm)、传代时间(tG)以及抑制率(I)等热动力学常数. 结果表明：在0～4.0×10-5 mol·L-1浓度范围内，生长速率常数(k)和抑制率(I)均与浓度成一定的线性关系. 生长速率常数(k)和最大产热功率(Pm)随着CdTe(QDs)/TiO2的浓度增加而下降，而传代时间(tG)和抑制率(I)随着CdTe(QDs)/TiO2 的浓度增加而增加；其中，CdTe(QDs)/TiO2的生长速率常数斜率(0.0001)小于TiO2的生长速率常数斜率(0.0005)，可以初步判断CdTe(QDs)/TiO2对E. coli的代谢影响较TiO2要大. TiO2和CdTe(QDs)/TiO2对E. coli代谢活性均有一定的抑制作用. 在相同浓度时，CdTe(QDs)/TiO2的抑制率斜率(0.84)大于TiO2的抑制率斜率(0.26)，进一步说明了CdTe(QDs)/TiO2相比TiO2具有对E. coli 更强的细菌抑制作用；结合Hadama荧光显微方法，进一步佐证了CdTe(QDs)/TiO2相对于TiO2表面结构的改变可能是导致其抗菌效果较好的主要原因之一. 从而为深入揭示纳米材料影响微生物生长代谢过程的热动力学规律和细胞损伤机制提供理论支撑.

关键词: CdTe(QDs)/TiO2, 大肠杆菌, 抗菌活性, 微量热, 热动力学

CdTe quantum dots (QDs) and CdTe(QDs) sensitized-TiO2 nanocomposites were synthesized by hydrothermal and self-assembly method, and the suspension of CdTe(QDs)/TiO2 and TiO2 were dubbed into the concentration of 1×10-2 mol/L. When a small ring of nutrient broth on E. coli was added into 5 mL LB medium, then E. coli was dubbed approximately the concentration of 1×106 cell/mL. The effect of CdTe(QDs)/TiO2 nanocomposites on E. coli was evaluated by a LKB-2277 Bioactivity Monitor using the stopped-flow method at 37.0 ℃. By analyzing the thermogenic power-time curves, thermokinetic parameters such as growth rate constant (k), maximum heat power of growth phase (Pm), generation time (tG) and inhibitory ratio (I) were determined. The results showed that both k and I have linear correlations with the concentration of nanocomposites in the scope of 0～4.0×10-5 mol·L-1. The value of k and Pm decrease while tG and I increase with increasing concentrations of the CdTe(QDs)/TiO2 nanocomposites added into the microbe suspension. Wherein, the slope of growth rate constant (k) on CdTe(QDs)/TiO2 is less than the slope of growth rate constant (k) on TiO2, can you initially determine CdTe(QDs)/TiO2 nanocomposites has larger effect than TiO2 on E. coli. To some extent, CdTe(QDs)/TiO2 nanocomposites and TiO2 have the metabolic activity on E. coli, the slope of inhibitory ratio (I) (0.84) on CdTe(QDs)/TiO2 is greater than the slope of inhibitory ratio (I) (0.26) on TiO2 at the same concentration. Compared with TiO2, CdTe(QDs)/TiO2 has higher antibacterial activity on E. coli. Combining the visual method of Hadama fluorescence microscopy. The CdTe(QDs)/TiO2 nanocomposites shows a better antibacterial activity on E. coli than that of nano-TiO2 because of the changes of surface structure. Our results also provide theoretical brace in order to investigate further on the impact of nanomaterials on the metabolic processes of microbial growth and the kinetics and mechanisms of cell damage.

Key words: microcalorimetry, CdTe(QDs)/TiO2, E. coli, antibacterial activities, thermokinetics