利用矽奈米粒子放大電流訊號之電化學感測器應用於單一細菌檢測

Nanoparticles-Based electrochemical biosensor for Single Bacterium Detection by Redox Signal Amplification

文柏超(Po-Chao Wen)

指導教授 ： 曾繁根

國立清華大學/原子科學院/工程與系統科學系/碩士(2013年)

摘要

細菌的快速分離和檢測在臨床醫療診斷、食物中毒、水汙染和生物恐怖攻擊等領域是極為重要的發展議題。傳統細菌檢測需先進行菌株培養數天後，再利用特定的染色或是免疫代謝等方法，來判讀菌種與濃度。針對敗血症而言，最重要的目標在於縮短檢測時間至1-2 小時內判定菌種，同時在病人尚未發病或是發病初期的階段就能夠在病人的檢體內(血液、尿液等) ，直接分離並檢測出細菌的濃度。
第一部份我們發展一實驗室晶片結合磁珠的分離技術進行樣本的前處理與濃縮，同時利用奈米粒子放大電化學氧化還原訊號。在本團隊過去的研究成果中以金奈米粒子放大訊號的微流體晶片在45 分鐘內可有效的區別3 種細菌(K. pneumoniae, S. aureus and P.Aeruginosa) ，而樣本的最低檢測極限值可達3.3 cell/μL。為了改善檢測極限值，我們使用大孔洞的矽奈米粒子(Mesoporous Silica Nanoparticles ，簡稱MSNs)，此結構可比矽奈米粒子增加百倍以上的鍵結表面積，因此可放大更多倍的電化學氧化還原訊號，而使用矽奈米粒子所達到的檢測極限可達10 cells/ml ，檢測範圍在10-10000 cells/mL之間，證明此晶片已達到超高靈敏度之細菌檢測。
第二部分希望能以拉曼散射光譜來進行細菌檢測，同時選用大孔洞的矽奈米球來鍵結有拉曼訊號的分子，期望也能辨別不同菌種及達到單一細菌濃度的可能性。未來期望能發展二維的檢測方式，除了電化學檢測外再加上拉曼增強光譜來做雙重確認，可提升細菌檢測的準確性。

關鍵字

細菌檢測 ； 大孔洞矽奈米粒子 ； 電化學檢測 ； 磁珠

並列摘要

Sepsis is a serious infection disease usually caused by bacteria and posing immune system to attack body's own organs and tissues. Sepsis can be frightening because it can lead to serious complications that affect the functions of kidneys, lungs, brain, and hearing, and can even cause death. Traditionally, analysis of infectious bacteria is still based on culture-based protocols, which need days to obtain result. In addition, it can not be detected when the patient is in the initial stage with only several hundreds of bacteria in 1c.c whole blood. In order to push the detection limit, we use Mesoporous Silica Nanoparticles (MSNs). Porous Si-NPs give around 100 times binding surface area enhancement larger than solid Si-NPs can provide at the same size. The Porous Si-NPs give us over 2-3 order enhancement for Ox-Red signal. Mesoporous Silica Nanoparticles (MSNs) labeled with antibody were used as transducers to amplify the signal by increasing the signal to noise ratio, and reducing the response time.
S. aureus containing samples have been tested by using anti- S. aureus magnetic beads(MBs-pSAb) as capture phase and sandwiching afterwards with MSNs modified antibodies(sSAb-MSNs)detected using Cyclic Voltammetry (CV).A detection limit of 10cells mL-1. And a linear range from 10 to 104 cells mL-1 of S. aureus was obtained. The results show that this biochip system has a great potential for single-bacterium detection.

並列關鍵字

bacteria detection ； Mesoporous silica nanoparticles ； electrochemical detection ； magnetic beads

參考文獻

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