直接成長奈米碳管於軟性基板之生物感測器

A Flexible Direct-Growth CNT Biosensor

張云慈(Yun-Tzu Chang)

指導教授 ： 游萃蓉

國立清華大學/工學院/材料科學工程學系/碩士(2013年)

摘要

本研究利用化學氣相沉積法 (chemical vapor deposition, CVD)，在400 °C之低溫下，直接成長奈米碳管於軟性基板 (聚醯亞胺, polyimide) 上製備生物感測器。接著在奈米碳管以外之區域，鍍上具有生物相容性之聚對二甲苯 (poly-para-xylylene, parylene)，當作絕緣層，以利於往後製成可撓式生物感測器進行體內量測之應用。而奈米碳管表面之改質，會先以紫外線臭氧處理，再以1-(3-二甲氨基丙基)-3-乙基碳二亞胺 (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, EDC) 與N-羥基丁二酰亞胺 (N-hydroxysuccinimide, NHS) 作表面改質，使奈米碳管能與蛋白質接合。接著，依序固定人類血清白蛋白抗體 (anti-human serum albumin, AHSA)、小牛血清蛋白 (BSA) 阻斷劑，最後接合不同濃度之人類血清白蛋白 (human serum albumin, HSA) 來進行檢測。
在電性量測方面，本研究是利用電化學阻抗譜 (electrochemical impedance spectroscopy, EIS)，在交流電下，量測不同濃度之人類血清白蛋白並加以量化。結果顯示，在2 * 10^-12 mg/ml至2 * 10^-1 mg/ml之人類血清白蛋白濃度間生物感測器之阻抗變化與濃度有高度關聯性，並且此生物感測器之偵測極限可達3 * 10^-11 mg/ml。
本研究利用電化學阻抗式機制，用以定量檢測人類血清白蛋白之濃度，並成功地驗證了將奈米碳管直接成長於軟性基板上作為生物感測器之可行性。此外，藉由化學氣相沉積法的製程，以及直接成長之奈米碳管的3D結構，使感測器可以利用較簡單之方式製備，並且有較佳之偵測極限，使此軟性感測器在未來之應用有極大之潛力。

關鍵字

生物感測器 ； 軟性基板 ； 奈米碳管 ； 電化學阻抗式 ； 人類血清白蛋白

並列摘要

In this study, a biosensor was fabricated by growing carbon nanotubes (CNTs) directly on polyimide flexible substrate at low temperatures (400 °C) with chemical vapor deposition (CVD) process. Thereafter, a biocompatible polymer (parylene) was coated on the surface area without CNTs as an insulator for future applications in flexible biosensors for in-vivo sensing.
The surface of CNTs was modified with functional groups by utilizing UV-ozone, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), and N-hydroxysuccinimide (NHS) treatment to improve the biocompatibility for the following conjugation of protein. Following that, the sensing surface was modified with anti-human serum albumin (AHSA), blocked by bovine serum albumin (BSA), and then conjugated with different concentrations of targeted human serum albumin (HSA) for HSA detection.
The electrical properties of the biosensors, applied with various HSA concentrations, were measured and quantified by using an electrochemical impedance spectroscopy (EIS) system under AC conditions. Results showed that the impedance change was well correlated to the HSA concentration from 2 * 10^-12 to 2 * 10^-1 mg/ml, and exhibited a detection limit of the 3 * 10^-11 mg/ml.
In summary, the feasibility of the CNTs flexible biosensor for HSA detection was demonstrated by utilizing electrochemical impedimetry to quantify human serum albumin concentration. Compared to other CNTs flexible biosensors, because of the employment of CVD process and the 3D structure of the direct-growth CNTs, the biosensor proposed in this work could be fabricated by a simpler process and provide a good detection limit. It shows a great potential for future application of wearable biosensor and implanting detection.

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