石英微量天秤(Quartz Crystal Microbalance)是利用質量負載(Mass-Loaded)原理,藉由生物辨識層的薄膜,可以將被偵測的蛋白質(抗原或抗體),利用分析儀器準確辨識出濃度。本論文主要研究出一新型的QCM生物感測器,利用電鍍技術將鎳鈷合金沉積於基頻為10MHz的AT-cut切角的石英晶體表面上。由於鎳鈷金屬會與修飾過His-tagged後的蛋白質產生專一性的親和性吸附,運用此免疫機制,將生物素(Biotin)固定於QCM鎳鈷金屬層上,經由阻抗分析儀器量測頻率的結果,可以發現不同的生物素濃度對應到不同的頻率下降量。除此之外,在螢光檢測方面利用硝化纖維薄膜(NC membrane)與QCM生物感測器以免疫學分析方法以及高靈敏度LSIV機台檢測螢光影像,並驗證此QCM 生物感測器確實具有生物素吸附之效果。 此生物感測器的優點包含以下幾點: (1)檢測物質不受限制,偵測方式主要根據QCM 振盪器之原理,進行頻率量測; (2) 減少檢體的浪費,本研究每點樣本僅需6μl即可進行實驗; (3) QCM 可以重複使用,使用經稀釋過後的3%硝酸可將鎳鈷金屬層移除掉,可以進行重複實驗; (4) 成本低廉,使用現今純熟的電鍍技術將可大量製造生物感測器,以減少成本支出。
Quartz crystal microbalance (QCM) which makes use of the mass-load theorem by biologic recognition component can detect protein concentration accurately. This paper presents a novel Ni-Co alloy coated QCM biosensor fabricated by electroplating nickel and cobalt on the surface of 10-MHz AT-cut QCM. The biotin was immobilized on the coated surface by the affinity mechanism of Ni-Co alloy. Then, the immunoreactions can be performed on the QCM biosensors. The results show that the Ni-Co alloy coated QCM biosensor can provide specific binding with His-tagged biotin. For different biotin concentrations, the QCM produced different frequency shifts. In addition, fluorescent detection was also performed to show that the coated Ni-Co film has better nonspecific binding ability than nitrocellulose (NC) membrane to immobilize His-tagged proteins for target analyses. The advantages of this biosensor include (1) label-free detection based on the principle of QCM resonator; (2) minimal sample consumption (6 l of biotin each drop used in this study); (3) QCM is reusable the coated Ni-Co alloy can be removed by 3% nitrate acid, so that the QCMs can be re-electroplated as biosensors; (4) inexpensive fabrication process, the electroplating technique is well-developed and the equipment and materials are very cheap. Hence, the mass production of QCM biosensors would be available.