一般傳統微生物檢測法雖已可提供精確的結果，但此過程耗時且花費較高成本，故發展快速且精確的檢測工具，對於感染性致病菌的診斷仍極為重要的。擁有快速檢測且能結合多種功能性的交流電動晶片元件與其系統，即被寄予厚望。其中介電泳晶片是一種較常用的技術；其原理主要是透過金屬電極排列形成非均勻電場，來誘導微粒子產生固液界面之間的極化現象，因而促使溶液中之微粒趨往高或低電場區域移動，並藉此達到操控或分離粒子的功能。
本研究中建構一種藉由給予交流電訊號產生負介電泳力的三維晶片系統。此3D DEP晶片優點為：(1)樣本不需標記抗原抗體即可進行分離，以利其後可在線上搭配光學或電學之檢測，對生物醫學之檢測可減少繁雜與耗時的實驗過程。(2)此3D DEP晶片為使用交流電訊號的控制，因此可自動化儀器設備，將來更可結合光學檢測設備，使其便於檢測分析。(3)晶片對於檢測時間而言，只需短時間下即可完成分離，與傳統檢測方法比較，為較快速的方式。(4)將分離的微粒捕捉，且以影像軟體擷取捕捉面積，再回推微粒的濃度。
主要探討對乳膠微粒和細菌的捕捉之實驗參數，用於乳膠微粒最適當的調控溶液為去離子水，交流電訊號為20 V p-p和10 MHz。而用於細菌最適當的調控溶液，為PBS緩衝液配合280 mM D-mannitol來配製的等張溶液，其導電度為1300 S/cm，交流電訊號為20 V p-p和500 kHz的環境下。以2 m的乳膠微粒為樣本，流體速度約為0.75~ 1.25 mm/s，捕捉效率可達90%以上。若以E. faecium細菌為樣本，流體速度為0.75 mm/s，捕捉效率可達85%以上，捕捉時間經過6分鐘之際，我們發現其回推的濃度可趨於穩定，其結果與平板菌落數或濁度計等檢測法所得的相近，顯示本法對細菌數具可快速定量的目的。

The accurate result can be provided with the conventional detection of microorganism, but the procedures took more time and cost. To develop the fast and accurate detection system is very important for the diagnosis of pathogens. Among these techniques, dielectrophoretic (DEP) chip is a common method for the application of bio-particles manipulation. In classical DEP theories, it describes that the non-uniform electric field made by metallic electrode alignment product the polarization in the solid-liquid interface and it make dielectric particles to move the high or low intensity regions of electric fields, and then to be manipulated and separated.
It is important to research the proper conditions of trapping bio-particles in my experiment. If the samples are latex beads, we use DI water for medium, and the voltage of 20 Vp-p, frequency of 10 MHz and fluid velocity of 0.75~ 1.25 mm/s, respectively. The trapping efficiency can be above 90%. If the samples are microbes, we use PBS buffer mixed D-mannitol solution for the medium, and the voltage of 20 Vp-p, frequency of 500 kHz and fluid velocity of 0.75 mm/s, respectively. The trapping efficiency of E. faecium can be above 85%. The concentration tended to be stable after trapping microbes for 6 minutes. To compare with other conventional detection techniques, like the turbidity meter and plate counting procedures, the concentrations are close. Applications for the 3D DEP chip will include the quantification of microbes in foodstuffs or environment. According to the results, this chip can be promoted to be a lab-on-a-chip in the future.

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