本研究結合了半導體固態製程、矽表面化學改質、生物 DNA 雜交反應等技術，以電阻抗變化測量取代傳統的螢光標記法，並以奈米金粒增強差異來作 DNA 序列的檢測。 首先利用固態製程的方法在矽晶片上長成一層二氧化矽薄膜，於其上以金為材料製作成對的微電極，其中包括各種不同寬度的微電極，接下來利用表面化學改質方法，將捕捉 DNA 與微電極間的二氧化矽層以共價鍵結合，再將目標 DNA 與探針 DNA 利用雜交反應結合至微電極間，最後將金奈米粒子以金硫鍵結合至 DNA 5’ 端。將上述過程處理後的晶片，使用 Keithley 4200 及 HP4284 下針在微電極上，量測其在 1 MHz 頻率下的阻抗值；總共測量數十個電極對，包括各種不同電極距離的電極對以評估電極距離對電性量測的影響。 結果顯示當微電極間距越小時，所量測出有雜交反應與無雜交反應之阻抗值差異越大，證實了此種電性量測方法不但可以分辨出是否有雜交反應的產生，還可以藉由電極間距微小化，使量測結果更為敏感。透過此種電性量測方法，可以偵測出 DNA 上的基因序列，同時製成 VLSI 的大量檢測方式，來節省成本，增加量測的正確性。 This research combines with semiconductor procedure, silicon surface chemical process and DNA hybridization etc. We utilize difference of impedance to replace traditional fluorescence label. Furthermore we utilize gold nanoparticle to enhance difference of signals for measurement of DNA sequences. First, we use semiconductor procedure to deposit silica film at silicon wafer, and plate with a pair gold microelectrode on the chips that have various widths of electrode. Second we bond capture DNA on SiO2 film between electrodes by covalent bond. Then we bond target DNA and probe DNA between microelectrodes by DNA hybridization. Finally we bond gold nanoparticle at 5’end of DNA by Au-S bond. We use Keithley 4200 and HP4284 to probe processed chip and measure the impedance at 1 MHz. In total we probe more than ten electrodes that include various electrode widths so as to estimate effect of electrode width on electric measurement of DNA hybridization. We find that when electrodes are more and more narrow, the differences of impedance between hybridization and nonhybridization are more and more obvious. These results verify that this electric measurement can’t only recognize occurring of DNA hybridization, but also make results more sensitive by reducing electrode widths. As the result of this method, we could detect the gene sequences of DNA, save the cost, and improve accuracy of measurement.
