現今DNA的應用越來越廣泛，在技術上也更趨成熟，因此可以藉由DNA的專一性特點來分析檢驗樣品中是否含有目標DNA。這篇論文提出兩種檢驗DNA的方法，並且利用基本的DNA雜合反應(Hybridization)來進行實驗。
應用生物相容性好的金電極來當感測表面，當電極表面發生雜合反應時，表面會累積更多的DNA，因此表面的電荷增加，同時DNA會使得電雙層電容減小。這篇論文分別利用這兩種變化設計其感測電路，取代傳統螢光標定的方式。第一種方法是感測DNA的本質電荷，利用結合金電極的互補式金氧半製程相容的延伸閘極式電晶體(EGFET)感測器和讀出電路來讀取出DNA造成的電荷變化，這電荷變化會改變電極表面電位，此電位改變即為感測電路的輸出電壓改變，並且使用一超低頻濾波器濾除高頻雜訊。第二種則是感測DNA所造成的電雙層電容變化，利用一個放大器及回授電容結合在水溶液中產生的電雙層電容來放大輸入訊號，最後，從輸出訊號倒推得到電雙層電容的變化。此外，也感測在不同目標DNA濃度下訊號的大小變化。

Applications of DNA assays have grown rapidly in recent years. Novel technologies are also developed for DNA assays. The high specificity of DNAs is useful for detecting target DNAs reliably. This thesis proposed two methods for detecting the hybridization and amplification of DNAs through biocompatible gold as microelectrodes. As hybridization occurs on the electrode surface, DNAs accumulate on the surface. Therefore, the charges increase and the double-layer capacitance of the electrode-electrolyte interface decreases. To avoid the conventional fluorescent-labeling methods, circuits for detecting either the intrinsic charges of DNAs or the impedance change induced by DNAs are proposed. To detect the intrinsic charges, EGFET integrated with gold electrodes and readout circuits are design to record the signal as an output voltage. In addition, an ultra low-pass filter with noise cancellation is employed to eliminate the high-frequency noise. To detect the change of the double-layer capacitance, an operational amplifier with a feedback capacitor array is connected to a gold electrode. As the double-layer capacitance changes with the DNA binding to the electrode surface. The capacitance change is amplified as an output voltage. Both type of circuits are integrated with gold microelectrode arrays on a single chip. The capability of the chip to detect the hybridization and amplification of DNAs are tested.

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