微電極介電泳阻抗式生醫感測元件於腸炎弧菌偵測之研究

Abstract

腸炎弧菌為一種人類腸道之病原菌，誤食受腸炎弧菌汙染的海鮮經常會造成急性腸胃炎，在世界各地因為腸炎弧菌造成集體食物中毒的案件層出不窮，尤其以亞洲為腸炎弧菌的好發區域。偵測腸炎弧菌的方法主要以耗時之傳統生物檢測法來偵測，因此、生醫感測器提供了另一種檢測的選擇。本論文利用微電極介電泳阻抗式生醫感測元件來偵測受到介電泳力聚集濃縮於晶片表面的腸炎弧菌，本研究之生醫感測系統感測區之最大電極面積僅有0.19 mm2並且不需要添加任何氧化還原探針，而是利用介電泳力捕捉並聚集散佈於溶液中的腸炎弧菌以達到濃縮的效果。首先利用數值模擬介電泳力在本研究系統中的效果，並實際以介電泳力操控聚苯乙烯珠以及腸炎弧菌。最後以阻抗量測受介電泳力聚集吸附於晶片表面的腸炎弧菌，本研究利用不同尺寸的電極偵測腸炎弧菌，發現尺寸較大的電極能夠有較大的變化量。另外、晶片表面也修飾上抗腸炎弧菌之抗體以增加偵測的靈敏度與選擇性，接著利用等效電路模擬實際實驗的阻抗量測結果，由等效電路發現腸炎弧菌貼附於晶片表面主要造成溶液電阻的改變。在無微流道結構下本研究之介電泳阻抗生醫感測元件能夠偵測到最低之腸炎弧菌致病的濃度1×10^5 CFU/ml。

Vibrio parahaemolyticus is one of pathogens in the human intestines. Consumption of seafood contaminated with Vibrio parahaemolyticus usually leads to the development of acute gastroenteritis. Food poisoning via Vibrio parahaemolyticus has been reported throughout the world and particularly severe in Asia. Ususlly diagnosis of Vibrio parahaemolyticus is performed through biological method like plating which takes days. Biosensors provide alternative detection methods within 30 minutes. This study utilized the microelectrode-dielectrophoresis impedance biosensor to detect aggregated Vibrio parahaemolyticus on the surface of the chip by dielectrophoresis. The area of the maximum electrode of the sensor is 0.19 mm2, and this dielectrophoresis impedance biosensor did not require the addition of any redoxs probe in the system. This biosensor then utilized dielectrophoresis to manipulate and concentrate the Vibrio parahaemolyticus in the solution. First of all, the results of dielectrophoresis were theoretically simulated. Subsequently, polystyrene beads and Vibrio parahaemolyticus were manipulated by dielectrophoresis. And, Vibrio parahaemolyticus were detected by the impedance sensor subsequently. This study also investigated the effect of electrode size. To improve the sensitivity and specificity of detection, the surface of chip was modified with anti-Vibrio parahaemolyticus antibodies. The data from impedance measurements were analyzed and an equivalent circuit was built. Based on the model, solution resistance dominates the impedance change caused by the detection of Vibrio parahaemolyticus. The microelectrode-dielectrophoresis impedance biosensor detected a minimum of 1×10^5CFU/ml of Vibrio parahaemolyticus without use of micro-fluidic channel.