摘要
目的利用发生响应性聚集后的金纳米粒子体系的较强的光热特性,研究其对细菌的体外光热杀伤作用。方法通过Au-S键反应将合成好的多肽A和多肽B分别修饰到金纳米粒子(GNPs)表面,然后等比例混合组成GNPs system。首先利用动态光散射(DLS)和透射电镜(TEM)研究其在弱酸性条件下的响应性聚集情况,利用多功能酶标仪研究其在在弱酸性条件下的紫外吸收变化;然后为了了解该纳米粒子在菌液中的光热转换情况,分别测定其在弱酸性条件下溶液内和与细菌作用后的温度变化曲线;进一步考察其体外抗菌效果。结果 DLS检测到合成的GNPs system在弱酸性条件下粒径由16 nm增大到900 nm左右,并在TEM下可见明显的聚集体,并且在650~900 nm的紫外吸收信号明显增高。在模拟细菌的弱酸性环境下,GNPs system在激光照射条件下均实现了溶液和细菌混合溶液的快速升温,且最高温度可达69. 8℃,与对照组GNPs-PEG2000相比具有显著的统计学差异;体外抗菌实验结果显示,GNPs system对金黄色葡萄球菌的杀伤力最强,50μg/m L浓度时就可杀死约50%的细菌;浓度为200μg/m L时基本上可以完全杀死,与对照组GNPs-PEG2000相比较具有显著的统计学差异。结论本研究为GNPs的设计提供了新的思路,为GNPs用于光热治疗提供了新的方法。
Objective To study the photothermal killing effect on bacteria means of the strong photothermal properties of gold nanoparticles system( GNPs system) after responsive aggregation. Methods Synthesized peptides A and B were modified at their surface by gold nanoparticles( GNPs) through the Au-S bond reaction,and then mixed at equal proportions to form the GNPs system. First,dynamic light scattering( DLS) and transmission electron microscopy( TEM)were used to assess the responsive aggregation under weakly acidic conditions. UV absorption changes under weakly acidic conditions were measured by a multifunction microplate reader. In order to understand the photothermal conversion of the nanoparticles in the bacterial suspension,their temperature curves in the solution under weakly acidic conditions and after treated with bacteria were measured,respectively. Finally,the antibacterial effect was tested in vitro. Results The particle size of the synthesized GNPs system was increased from 16 nm to 900 nm as detected by DLS under weakly acidic conditions.Obvious aggregates were observed by TEM,and the UV absorption signal was significantly increased at 650~ 900 nm. Under the weakly acidic conditions of simulated bacteria,the GNPs system achieved a rapid temperature rise of the solution with mixed bacterial under laser irradiation conditions. The highest temperature was 69. 8°C,significantly different from the control group of GNPs-PEG2000. The result of antibacterial experiments in vitro showed that the GNP system had the strongest killing effect against Staphylococcus aureus,which was 50% and 100% killing of the bacteria at concentration of 50 and 200 μg/m L,respectively,showing a significant difference compared with the control group of GNPs-PEG2000. Conclusions This study provides a new approach for the design of GNPs and a new method to apply GNPs to photothermal therapy.
引文
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