在本實驗室先前的研究中，利用電化學安培偵測法做為毛細管電泳晶片的末端檢測方法，並將微管道、偵測電極等利用微機電製程方式整合於單一載玻片之上達到微小化的目的。但由於電化學法礙於其偵測原理，即樣本需具有氧化還原活性才能產生電流響應，而無法廣泛應用，故欲發展導電度偵測法來彌補電化學法之不足。
在晶片的製作上，微管道係以SU-8光阻製作凸模於矽晶圓上，再利用polydimethylsiloxane (PDMS)灌製凹膜而成，其寬高各為150及13 um，總長55 mm(其中分離長度為47 mm)，而利用微機電製程製作於載玻片上之微小電極寬度為300 um，以對極方式(間隙為30 um)排列於微管道末端。PDMS微管道與鍍有微型電極之載玻片在清洗後利用物理性吸附之方式貼合，以利重覆使用。本實驗的待測物包含了鋰(Li+)、鈉(Na+)、鉀(K+)等金屬離子，並以20 mM之2-(N-morpholino)ethanesulfonic acid (MES)+ histidine (His)做為緩衝液。實驗過程先以200 V/cm 之注入電場將樣本持續注入10 sec，隨後施加110 V/cm之樣本驅動電壓。
實驗結果對於所偵測之Li+、Na+及K+等金屬離子樣本在0.1 mM ~ 1 mM濃度範圍中有良好的線性表現，其R^2值均在0.99以上。而在混合樣本方面，搭配110 V/cm之分離電場成功地於100秒內分離濃度各為1 mM之鋰(Li+)、鈉(Na+)、鉀(K+)之混合溶液。另外對所獲得之偵測訊號亦利用毛細管電泳及導電度相關公式原理做實驗數據與理論公式間的差異計算，其誤差在5%以內，足以證明實驗訊號之正確性。未來藉由3D晶片製程以及加長分離管道後期望能在檢測極限上有所提升到達生醫應用之層級。

In our previous research, we have demonstrated a capillary electrophoresis microchip with amperometric detection. We integrate both micro-channel and detecting electrodes by microelectromechanical system (MEMS) into one chip to achieve lab-on-a-chip goal. Due to the principle of amperometric detection, that is, only samples with red-ox activities will have current response, we can’t apply this chip to detect metal ions. So we want to develop conductometric method to complement the disadvantage.
We spin SU-8 on the silicon wafer to build a mold and cast the channel with PDMS. The micro-channel is 150 and 13 um in width and height respectively and a total length of 55 mm (the effective separation length is about 47 mm). The micro-electrodes are arranged in opposite to each other with a gap of 30 um with in-channel mode. In this research, metal ions including Li+, Na+, and K+ were used as samples. The sample injection electric field is 200 V/cm and lasting for 10 sec. After that we apply a separation electric field (110 V/cm) to drive the samples toward detection electrodes.
As a result, The chip presents a good linearity in the concentration range from 0.1 mM to 1 mM for all ion species with R^2 values over 0.992. We also separated 3-sample mixture including 1 mM Li+, Na+, and K+ successfully. Further more, we explain the result signals with CE and conductometry principles in order to obtain the validity and the error is less then 5%. We hope this chip may apply to biomedical applications with further improvements in 3D chip design.

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