氧化銦鎵鋅薄膜電晶體結合微流道於生化反應的分析和生物檢測

Abstract

這篇論文介紹以氧化銦鎵鋅薄膜電晶體與感測金屬電極組成之可重複使用生物感測器偵測生物分子，此研究分兩部分： 第一部分，我們採用薄膜電晶體生物感測器結合聚二甲基矽氧烷直線型微流道。接著以溶菌酶及其適體三乙醯殼三糖作為動態反應分析的探討，首先，單獨注入溶菌酶溶液和三乙醯殼三糖至流道中確認電流變化，來建立由溶菌酶濃度與電流變化關係的曲線。接著，將三種濃度比例之溶菌酶以及三乙酰殼三糖混合在離心管中，控制兩者的反應時間；對擷取之電流變化，考量屏蔽效應進行修正後可藉已建立之溶菌酶濃度與電流變化關係將電流變化轉為剩餘溶菌酶濃度。以此，可建立剩餘溶菌酶濃度與反應時間擬合曲線。曲線可幫助我們藉化學公式得到反應級數、結合速率常數與分解常數。其中，分解常數之結果為39.10 μM，與其他團隊提出之數值十分接近。 第二部分，探討了肌鈣蛋白I來測試薄膜電晶體生物感測器的靈敏度。首先，先使用了螢光實驗來確定抗體是否有被交聯劑抓住。接著，探討了功能化的電性。然後注入不同濃度的肌鈣蛋白I來確認薄膜電晶體生物感測器的靈敏度。薄膜電晶體生物感測器可以量測到最低1 pg/mL濃度的肌鈣蛋白I。接下來，探討了聚二甲基矽氧烷與生物分子之間的疏水性效應。儘管PDMS微流體通道在與玻璃基板結合之前先經過紫外線臭氧處理，先轉變為親水性，但PDMS的疏水性恢復是不可避免的。由於疏水性效應，生物分子會自發吸收到PDMS表面。解決方法是通過在紫外線臭氧處理後將去離子水注入微流體通道以抑制疏水性恢復。為了驗證疏水作用的影響，在金傳感墊和PDMS表面進行了分別進行了熒光實驗。 結果表明，浸入水和不浸入水的PDMS之間存在顯著差異。 最後，TFT生物傳感器能夠在0.01× PBS緩衝溶液中檢測到10 fg/mL肌鈣蛋白且各個濃度的標準差也變小。

In this thesis, a reusable biosensor consists of an Indium-Gallium-Zinc-Oxide (IGZO) thin-film transistor (TFT) and a microfluidic channel chip is demonstrated for detecting biomolecules. The thesis includes two parts. In the first part, a linear-type polydimethylsiloxane (PDMS) microfluidic channel is integrated with the TFT biosensor is demonstrated. Afterwards, the kinetic reaction of lysozyme and tri-N-Acetylglucosamine (NAG3) are investigated. First, several concentrations of lysozyme solutions and NAG3 are injected into the microfluidic channel to measure drain current variations. Then, the curve of correlation between lysozyme concentrations and drain current changes is constructed. Then, three mixing ratios of lysozyme and NAG3 solution are incubated in the micro-centrifuge for different periods of reaction time. Due to the screen effect, the extracted drain current responses of lysozyme-NAG3 solution are calibrated by the revision factor. Afterwards, the fitting curves of remained lysozyme concentration versus reaction time are illustrated. The curves provide the remained lysozyme information that can be calculated the partial orders, association rate constant, and dissociation constant by biochemical formulas. It is noteworthy that the derived dissociation constant is 39.10 μM, which is close to the results reported by previous researches. In the second part, cardiac troponin I (cTnI) are investigated to measure the limit of detection of TFT biosensor. First of all, to confirm antibodies were captured by cross-linkers, a fluorescent experiment was measured. Then, the electrical properties of functionalization are discussed. Afterwards, different concentrations of cTnI solution are injected into the microfluidic channel to measure the limit of detection for the TFT biosensor. The limit of detection of TFT biosensor is 1 pg/mL cTnI. Next, the hydrophobic interaction between PDMS and biomolecules is investigated. Although PDMS microfluidic channel is treated by UV Ozone to convert into hydrophilic before binding with the glass substrate, hydrophobic recovery of PDMS is unavoidable. Due to the hydrophobic effect, biomolecules are absorbed spontaneously on the PDMS surface. The problem can be solved by injecting deionized (DI) water into the microfluidic channel after UV Ozone treatment to inhibit hydrophobic recovery. Two fluorescent experiments in sensing pad and PDMS surface are measured to verify the hydrophobic interaction. The results show that there is a significant difference between PDMS with immersing water and without immersing water. Finally, the TFT biosensor is able to detect 10 fg/ml cTnI and the standard deviation of each measurement is also decreasing in the 0.01× PBS buffer solution.