- 學位論文
磁場控制Ag-Fe3O4奈米粒子應用於大腸桿菌之抑制
Magnetic control of Ag-Fe3O4 Nanoparticles and its antibacterial application on Escherichia coli
摘要
銀作為抑菌材料已有很長的歷史，其優勢除抑菌效果卓越外，過程中亦無消毒副產物之增生。過去若須增強抑菌效能，最直接之方法為增加銀粒子濃度，以提升與細菌接觸之面積，若能藉由非接觸式外力操控銀粒子與細菌之接觸，預期於相同濃度下能達到更好的抑菌效果，因此，本研究遂結合銀抑制細菌的機制與操控四氧化三鐵運動的磁控系統，擬開發一套可提升銀抑菌的效能及能回收再利用的技術。 本實驗透過化學共沉法製備具有磁性及抑菌效能的Ag-Fe3O4奈米粒子，粒徑尺寸約在40至80奈米間。抑菌實驗係透過調配0.6wt.%、1.8wt.%、3.0wt.%、4.2 wt.%、5.4wt.% 、6.6wt.%等六種不同重量百分比濃度的Ag-Fe3O4粒子置入大腸桿菌溶液中，磁控系統則分別使用50 rpm、80 rpm、100 rpm、120 rpm、200 rpm等五種不同轉速以旋轉磁場攪動溶液中的粒子，每組溶液均經過3分鐘的攪動，再利用強力磁鐵將粒子吸附於底部並抽取其上層液體進行檢測，經分光光度計量測細菌的吸光度以了解殘餘細菌量，實驗結果顯示在重量百分比濃度5.4 wt.%與100 rpm轉速能達到99.4%的抑菌效果。
並列摘要
Silver has been utilized as a bacteriostatic material for ages. Apart from its excellent antibacterial effect, harmful byproducts during the process will not be generated while sliver sterilization was applied. In general, the antimicrobial efficacy of silver increases with increasing the content of Ag particles. However, if these particles can be manipulated to increase their contact with bacteria, a higher antibacterial effect could be expected with a lower content of Ag particles. In this study, a magnetic manipulation technique is developed to control the movement of Ag-Fe3O4 nano-composites materials for enhancing the antimicrobial effect of silver. The Ag-Fe3O4 magnetic nanoparticles were prepared by co-precipitation method. The size range of these particles was from 40 nm to 80 nm. Experiments were carried out to investigate the antimicrobial effect of magnetically controlled Ag-Fe3O4 nanoparticles on Escherichia coli. With respect to the weight of the Escherichia coli solution in petri dishes, the prepared concentrations of the nanoparticles for each experiment were 0.6 wt.%, 1.8 wt.%, 3.0 wt.%, 4.2 wt.% , 5.4 wt.%, and 6.6 wt.%. The solutions were stirred by utilizing the motor in the magnetic manipulation device at rotation speeds of 50 rpm, 80 rpm, 100 rpm, 120 rpm, and 200 rpm, 3 minutes for each test. The Ag- Fe3O4 nanoparticles in the solutions were then attracted to the bottom of the petri via a magnet and the supernatants were taken out to check the amount of the remaining Escherichia coli. Experimental results showed that the best antibacterial effect was achieved at the concentration of 5.4 wt.% with driving frequency of 100 rpm, where the antibacterial effect reached to 99.4%.