可標靶致病菌的醫療性金奈米粒子

Abstract

抗生素雖然已可有效地用於抑制致病菌的生長，然而多年來抗生素的濫用，導致已有對抗生素產生抗藥性細菌的誕生。另一方面，細菌污染所造成的食物中毒需要有效且快速的分析方法以提供有用及正確的訊息進行致病菌身份的鑑定。在本論文中，對致病菌具有標定能力的金奈米粒子已被成功的開發出來，並且可用以快速篩檢細菌的探針及抑制細菌生長的奈米抗生素。本文的第一部分，介紹了藉由萬古黴素與四氯金酸的一鍋化反應所合成出來的官能化金奈米粒子。此官能化金奈米粒子之粒徑平均大小約為8.4±1.3 nm,且在pH 6的溶液中表面電位為 -17.7 mV。此官能化奈米粒子對於革蘭氏陽性菌、革蘭氏陰性菌及抗藥性細菌均具有良好的辨識性及抑制能力。另一方面，對於細胞所造成的毒性也是相當低的。因此本文也進行了以此金奈米粒子投藥於金黃色葡萄球菌感染的巨噬細胞中的抑菌實驗，結果顯示此官能化的金奈米粒子可確實用於抑制巨噬細胞中金黃色葡萄球菌的生長。本文的第二部分則以對金黃色葡萄球菌及抗藥性金黃色葡萄球菌具有辨識能力的胜肽片段合成出表面修飾有此胜肽片段的金奈米粒子探針。所得的金奈米粒子為球狀結構，其平均直徑約為7.6 ± 1.2 nm。此外，實驗中也進一步的將此胜肽官能化金奈米粒子與表面輔助雷射脫附游離質譜法結合用於快篩含金黃色葡萄球菌污染樣本的分析。結果顯示，此快篩方法對於有金黃色葡萄球菌污染的樣本之偵測極限約在幾十個細菌數的等級。總括而言，本論文研究出的官能化金奈米粒子可以做為菌種快篩的親和探針及抑菌的奈米抗生素，因此這些官能化金奈米粒子應有進一步發展成抗菌劑和菌種快篩試劑的潛力。

Generally, antibiotics can be used to effectively inhibit the cell growth of pathogenic bacteria. However, the extensive use of antibiotics has resulted in the emergence of antibiotics-resistant bacterial strains. Additionally, food poisoning caused by pathogenic bacteria requires effective analytic methods, which can provide accurate and informative results for rapid bacterial identification. In this dissertation, theranostics gold nanoparticles were generated to be used as detection probes and antibiotics. In the first part of thesis, the generation of vancomycin directed synthesis of gold nanoparticles (Van-AuNPs) was demonstrated through one-pot reactions. The average size of the Van-AuNPs was 8.4 ± 1.3 nm with the zeta potential of ~-17.7 mV at pH 6. Furthermore, the generated Van-AuNPs have the targeting capacity and antibiotic activity toward pathogenic bacteria including Gram-positive, Gram-negative, and antibiotic-resistant bacteria. The cell toxicity of the Van-AuNPs was low. The results also demonstrated the possibility to use the Van-AuNPs to effectively inhibit the cell growth of Staphylococcus aureus in the S. aureus infected macrophage cells. In the second part of the thesis, a new type of functional AuNPs immobilized with peptide aptamers, which can be used to selectively target S. aureus and methicillin-resistant S. aureus, was generated. The generated AuNPs were spherical, and the diameter of the purified AuNPs was 7.6 ± 1.2 nm. A rapid screening approach was demonstrated by combining the use of the functional AuNPs with surface-assisted laser desorption/ionization mass spectrometry for detecting the presence of S. aureus from sample solutions. The results show the detection limit was as low as few tens bacterial cells. In summary, two types of functional AuNPs have been generated and used as affinity probes for targeting pathogenic bacteria. The applications of the generated AuNPs include in inhibition of the cell growth of pathogenic bacteria and in rapid sensing of target bacteria. The results show the potential uses of the generated functional AuNPs as antibiotic agents and rapid-sensing agents.