[競賽範例] 2016年專題論文競賽範本

雙變色之新穎性螢光靜電紡絲奈米纖維及其pH與三價鐵離子感測應用

(題目：標楷體 粗體 大小14)

江岱樺、陳伯瑜、郭霽慶*

(作者：標楷體 大小10)

國立台北科技大學 分子系暨有機高分子所 (單位：標楷體 大小10)

E-mail: kuocc@mail.ntut.edu.tw  (聯絡信箱：Times New Roman  大小10)

ABSTRACT: Novel dual-ratiometric fluorescent electrospun (ES) nanofibers featuring high sensitivity for pH and ferric ion (Fe3+) were prepared using binary blends of poly(2-hydroxyethyl methacrylate-co-N- methylolacrylamide-co-nitrobenzoxadiazolyl derivative) (poly(HEMA-co-NMA-co-NBD)) and a spirolactam rhodamine derivative (SRhBOH) by employing a single-capillary spinneret. The HEMA, NMA, and NBD moieties were designed to exhibit hydrophilic properties, chemical cross-linking, and fluorescence (fluorescence resonance energy transfer (FRET) donor), respectively. The fluorescence emission of SRhBOH was highly selective for pH and Fe³⁺; when SRhBOH detected acidic media and Fe3+, the spirocyclic form of SRhBOH, which is nonfluorescent, was transformed into the opened cyclic form and exhibited strong fluorescence emission.

The emission colors of ES nanofibers in acidic or Fe³⁺ aqueous solutions changed from green to red because of FRET from NBD (donor) to SRhBOH (acceptor). The off/on switching of the FRET process was modulated by adjusting the SRhBOH blending ratio, pH, and Fe³⁺ concentration. Poly(HEMA-co-NMA-co-NBD) ES fibers blended with 20% SRhBOH showed high sensitivity

in sensing Fe³⁺ and pH because of the substantial 57 nm red shift in emission as well as substantial reversible dual

photoluminescence. The prepared FRET-based dual-ratiometric fluorescent ES nanofibrous membranes can be used as “naked eye” sensors and have potential for application in multifunctional environment sensing devices.

摘要：本研究利用共聚合合成與靜電紡絲加工技術，將具備雙重螢光放光特性的高分子poly(HEMA-co-NMA-co-NBDOMA)/SRhBOH混合物，製備成能感測三價鐵離子(Fe³⁺)及pH值的多功能新穎性奈米纖維，並藉由螢光共振能量轉移(Fluorescence Resonance Energy Transfer)(FRET)的機制，來達到多變色螢光的放光表現。

首先，成功利用自由基聚合(Free radical copolymerization)合成poly(HEMA-co-NMA-co-NBDOMA)共聚高分子(其中HEMA為高吸水性材料、NMA提供化學交聯、NBDOMA則是綠色螢光放光基團)，混摻入不同比例的橘紅色螢光SRhBOH(可感測pH與螯合Fe³⁺)，調控靜電紡絲加工參數得到多功能性奈米纖維，以SEM觀察其纖維形態，利用PL探討光物理特性。結果顯示，隨著pH降低以及Fe³⁺濃度的增加，奈米纖維會因螢光基團產生FRET機制，自綠色螢光轉變至橘紅色螢光: 主要是因為SRhBOH處於中性、鹼性或無三價鐵離子的環境中，不會放出螢光(spirolactam form)，此時綠色螢光纖維來自NBDOMA，而當處於酸性或存在三價鐵離子的環境中，開啟SRhBOH(受體)開關，故會由NBDOMA(供體)綠光能量轉移給SRhBOH(受體)，而從綠光轉而放出橘紅色螢光(ring-opened acyclic form)。SRhBOH的混摻比例越高，能量轉移機制越明顯，並且可藉由此調控比例，達到偵測不同濃度的酸鹼與金屬離子環境對應出的顏色變化(綠光à藍綠光à黃光à橘光à紅光)。

綜上所述，此具金屬(Fe³⁺)以及pH值感測之螢光奈米纖維，具肉眼即可判定的綠色與橘紅色螢光之開關表現，且能夠重複再使用，本專題論文之預期效益即是此奈米纖維膜兼具金屬離子分離與感測的雙重功效，未來在生物及環境感測元件等相關領域，具相當大的發展潛力。

關鍵詞：螢光感測、靜電紡絲纖維、羅丹明B、螢光共振能量轉移(FRET)、Fe³⁺

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