請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/40975
標題: | 甲殼素對革蘭氏陰性菌懸浮細胞及生物膜亞甲基藍光動力殺菌效果之影響 Effects of chitosan on the efficacy of methylene blue mediated photodynamic therapy against Gram-negative bacterial planktonic cells and biofilms |
作者: | Jia-Lin Hong 洪佳麟 |
指導教授: | 黃慶璨 |
關鍵字: | 光動力治療,生物膜,亞甲基藍,甲殼素, photodynamic therapy,biofilm,methylene blue,chitosan, |
出版年 : | 2011 |
學位: | 碩士 |
摘要: | 生物膜 (biofilms) 為附著於物體表面生長的微生物群,可生長於醫療器材及傷口組織,形成持續性感染,對大部分殺菌劑有極強的抗性,因此不易治療。光動力治療 (photodynamic therapy) 為一新興的微生物感染治療方法,其殺菌能力不受細菌抗藥性影響而備受重視,已知對革蘭氏陽性之抗藥性菌株及生物膜具有殺菌效果,但對革蘭氏陰性菌的效果不佳,因此本研究探討以甲殼素 (chitosan) 促進光動力對革蘭氏陰性菌的殺菌作用。實驗結果發現亞甲基藍 (methylene blue) 光動力治療對革蘭氏陰性菌效果不彰,但經0.0004% 甲殼素處理10分鐘,光動力治療對革蘭氏陰性菌懸浮細胞的效果有顯著提升。在0.05% 甲殼素處理90分鐘,光照劑量480 J/cm2 的條件下,可對綠膿桿菌 (Pseudomonas aeruginosa) 生物膜完全殺菌。利用螢光光譜儀測定懸浮細胞的亞甲基藍激發量,發現激發量越高,殺菌效果越好,且當激發量超過約1 nmol/mL時可達完全殺菌,這與前人研究所發現光感物質激發量必須達到閾值 (threshold) 以上才能完全殺菌的現象一致。以甲殼素先處理,細菌的光感物質激發量顯著上升,這可說明甲殼素的確能幫助亞甲基藍吸附於菌體上。掃描式電子顯微鏡觀察發現經甲殼素處理後菌體會有聚集現象。雖甲殼素與光感物質的結合實驗無法完整解釋菌體吸附更多亞甲基藍的原因,但甲殼素合併光動力治療應是極具潛力的治療模式。 Biofilms are groups of microbes that attached to a surface. They can grow on indwell medical devices or human tissues, resulting in chronic or persistent infections. Because biofilms have stronger resistance to antibiotics than planktonic cells, those infections of biofilms are hard to treat. Photodynamic therapy (PDT) is an emerging method to treat microbial infections. So far, there is no strain resistant to PDT being observed. PDT is effective against Gram-positive planktonic cells and biofilms as well as drug-resistant strains. However, Gram-negative bacteria are more resistant to PDT. In this study, we used chitosan to enhance the efficacy of PDT. The results show that methylene blue-mediated PDT has a poor efficacy to Gram-negative bacteria, but it is more effective to planktonic cells treated with 0.0004% of chitosan for 10 minutes. Biofilms treated by 0.05% of chitosan for 90 minutes are also more sensitive to PDT. We observed that there is a threshold of methylene blue excitation level at 1 nmol/mL. If the excitation level of methylene blue is higher than the threshold, all the bacteria will be killed. After the treatment of chitosan, the amount of methylene blue binding to bacteria is increased, and the excitation level of methylene blue is higher. It implies that chitosan can enhance the binding between bacteria and methylene blue. The images taken by scanning electron microscope show bacteria aggregated after treatment of chitosan. Our result shows that chitosan have weak binding ability to methylene blue, it cannot explain the mechanism of chitosan enhancing PDT. However, the use of chitosan to enhance the efficacy of PDT may be a potent method. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/40975 |
全文授權: | 有償授權 |
顯示於系所單位: | 生化科技學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-100-1.pdf 目前未授權公開取用 | 9.86 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。