以奈米柱及薄膜電晶體製作高敏感度蛋白質感測器

Abstract

在這篇論文中，我們設計了一種以氧化銦鎵鋅薄膜電晶體並附有延伸金感測板構成的生物感測器。電晶體扮演著感應與訊號輸出的角色，而金感測板具有增加感測器的感測區域並可將待測的生化溶液與薄膜電晶體通道分隔開來的功能。我們的生物感測器利用氧化鋅奈米柱來增加感測面積，使得吸引抗體自身帶有的電荷的能力增強，來達成使感應器功能化的目的。此外，功能化後的感應器與蛋白質的鍵結時間能夠減少到十分鐘以下，顯示此感測器有良好的即時感測能力。我們測試了兩種蛋白質，一種是由培養的扁平上皮癌細胞萃取出的上皮生長因子，另一種則是小鼠血清裡的免疫球蛋白G。我們比較了生物感測器以及目前現有的蛋白質檢測方法的敏感度。利用這種全新、省時並且高敏感度的蛋白質檢測器，我們可以在0.1ng/ml的癌細胞溶液中專一性地量測到濃度為36.2 fM的上皮生長因子。更進一步的，我們可以在10pg/ml離體的小鼠血清溶液中專一性地量測到濃度為8.98fM的小鼠免疫球蛋白G。

We demonstrate a biosensor structure consisting of an IGZO (Indium-Gallium-Zinc-Oxide) TFT (thin film transistor) and a gold extended sensing pad. The TFT acts as the sensing and readout device, while the sensing pad ensures the isolation between biological solution and the transistor channel layer, and meanwhile increases the sensing area. The biosensor is functionalized by first applying ZnO nanorods to increase the surface area for attracting electrical charges of antibodies. Furthermore, the conjugation duration of the functionalized device with protein can be limited to less than 10 minutes, implying that the biosensor has the advantage for real-time detection. We detect two kinds of protein, one is EGFR (epidermal growth factor receptor) exacted from SCC cell line, another is mouse IgG in the mouse serum. We investigate the sensitivity with the conventional protein detection methods. By this novel structure, a time-saving and highly sensitive protein detecting process is developed. The bio-TFT is able to selectively detecting 36.2fM of EGFR in the total protein solution of 0.1ng/ml and, and selectively detecting 8.98fM of mouse IgG in the serum solution of 10pg/ml in vitro.