新型材料於仿生感測器及光催化之應用

黃惠琪(Hui-Chi Huang)

指導教授 ： 李育德 ； 陳信龍

國立清華大學/工學院/化學工程學系/博士(2006年)

摘要

中文摘要

本論文研究主要切割為仿生感測器與奈米碳球衍生物之應用兩部分。結合分子拓印光阻劑、微影製程及電化學訊號擷取系統，分子拓印修飾之超微仿生感測器已被開發。另一方面，二氧化鈦奈米粒子已成功承載於中空及包鐵奈米碳球上，並完成光觸媒與光電池的評估。
分子拓印型光阻劑由於穩定性佳、可與多樣的模版分子形成官能基互補之複合物、彌補生物辨識層的不足外，更重要的是其具備微影功能，方便修飾超微電極，利於發展攜帶式及植入式生物晶片。研究中主要合成降冰片烯系列及壓克力兩大系列分子拓印光阻劑。Albuterol於降冰片烯拓印電極之波峰訊號可達非拓印電極的八倍，但隨著電位掃瞄的次數增加，修飾層會逐漸澎潤脫落，而無法應用於超微晶片上。壓克力系列功能性高分子因具有長鏈醇基，故可安定附著於電極的表面，不會隨著電位掃瞄的過程而脫落。調整壓克力系列光阻劑配方比例與微影參數，可得最小線寬約20 μm。Albuterol於壓克力拓印晶片之波峰電流最大可為非拓印晶片的15倍，且由clenbuterol與terbutaline於純白金晶片（或電極）、壓克力拓印晶片（或電極）、壓克力非拓印晶片（或電極）與玻璃態碳電極再結合的程度，可發現壓克力拓印晶片（或電極）對albuterol具有選擇性。掃瞄式電子顯微鏡與原子力顯微鏡觀察的結果顯示拓印修飾層的表面比非拓印修飾層粗糙且多孔。壓克力功能性高分子與albuterol摻混的氫譜則顯示兩者間確實產生特殊之作用力，真實的立體構形得進一步利用分子模擬來探究。此外，在拓印晶片上，albuterol的氧化訊號與其濃度在區間1-50 μM與100-200 μM呈現良好之線性關係與再線性。
奈米碳球由多層封閉石墨層球殼所組成，其中心因可填入多種金屬，而衍生出多樣的應用。研究中我們利用簡單的溶膠凝膠反應，將二氧化鈦承載於中空及包鐵奈米碳球上。由高解析穿透式電子顯微鏡圖片及表面元素分析得知二氧化鈦以表面成核與成長的方式承載上中空奈米碳球，與承載上包鐵奈米碳球之異相凝結的方式不同。X光繞射圖譜可知承載上之二氧化鈦皆為銳鈦礦晶相。二氧化鈦承載上中空及包鐵奈米碳球之反射式紫外光-可見光吸收曲線幾乎遵循純奈米碳球之吸收曲線。一氧化氮光催化測試顯示二氧化鈦承載於中空及包鐵之奈米碳球有助於光催化效率的提高。另一方面，二氧化鈦承載上中空奈米碳球的含量只需為純二氧化鈦的0.07倍，即可得到相同降低共軛高分子螢光放射的強度。因此我們推測二氧化鈦與奈米碳球間應存在電荷轉移，可使產生之電子電洞對有效分離，進而提高光催化效率、降低共軛高分子螢光的釋出。由於包鐵奈米碳球良好的光催化效率，且封閉石墨層可有效保護鐵粒子使其長效具有磁性，將有助於光催化後的再回收，避免二次污染。

關鍵字

仿生感測器 ； 分子拓印 ； 微分脈衝法 ； 微影製程 ； 乙類促效劑 ； 二氧化鈦 ； 奈米碳球

並列摘要

Abstract

Combining molecularly imprinted photoresists (MIPhs), photolithography and electrochemical techniques, a multi-array sensor using MIPhs as the recognition element has been fabricated. Two kinds of MIPhs, norbornene and acrylic MIPhs, have been developed in this study. In comparison with MIPhs using norbornene copolymers as the functional polymers, the acrylic MIPh could adhere strongly to Pt surface and has a good resolution of 20 μm. Acrylic MIPhs were utilized to construct MIPh-based chips, which can discriminate albuterol from the interfering analogies, such as clenbuterol and terbutaline. Excellent selectivity toward these analytes was obtained for the molecularly imprinted chips as compared to molecularly non-imprinted chips, bare Pt chips and glassy carbon electrodes. Furthermore, the peak currents of albuterol measured on molecularly imprinted chips have good linear relations with its concentrations in the two ranges of 1 μM to 50 μM with the correlation coefficient (R) of 0.9995, and 100 μM to 200 μM with R of 0.9999 by differential pulse voltammetry. The surface morphologies of molecularly imprinted and non-imprinted layers observed by scanning electron microscope and atomic force microscope displayed significantly different features. Because of small size, light weight and high specificity towards the template molecule, the multi-array sensor developed in this work is potentially useful for determining trace electroactive species either in vitro or in vivo.

In the other part, TiO2 has been successfully immobilized on carbon nanocapsules (CNC) and Fe-filled CNC (Fe-CNC) using simple sol-gel methods. The high resolution TEM images indicated that the immobilization of TiO2 on Fe-CNC was driven primarily by heterogeneous coagulation, whereas surface nucleation and growth was the dominant mechanism for immobilizing TiO2 on acid-functionalized hollow CNC. The TiO2 immobilized on both CNC and Fe-CNC exhibited anatase phase as revealed by the X-ray diffraction patterns. In comparison with free TiO2, TiO2-coated CNC and TiO2-coated Fe-CNC displayed a good performance in the removal of NO gas under UV exposure. The TiO2-coated CNC exhibited effective quenching on the emission of a light-emitting conjugated polymer. This may imply that TiO2 immobilized on hollow CNC or Fe-CNC could promote the charge transfer for effective photodegradation of NO and quenching of the emission from conjugated polymer. Due to the advantages of easy recycling and good photocatalytic efficiency, the novel magnetic photocatalyst developed here has the potential in photocatalytic applications for pollution prevention.

並列關鍵字

biomimetic sensors ； molecular imprinting ； differential pulse voltammetry ； lithography ； albuterol ； titanium dioxide ； carbon nanocapsules

參考文獻

1.B. Sellergren (Eds.), Molecularly imprinted polymers: man-made mimics of antibodies and their applications in analytical chemistry, 1st ed. Elsevier, UK, 2001.

2.M. Komiyama, T. Takeuchi, T. Mukawa, H. Asanuma, Molecular imprinting from fundamentals to applications, 1st ed. Wiley-Vch, Germany, 2003.

3.S. Y. Lu, C. H. Chang, C. H. Yu, H. L. Chen, Y. H. Lo, J. Mater. Res., 20(2005)1523.

4.A. Hanprasopwattana, T. Ricker, A. G. Sault, A. K. Datye, Catal. Lett., 45(1997)165.

12.S. Y. Huan , G. L. Shen , R. Q. Yu , Electroanalysis, 16(2004)1019.