介電質加熱輔助奈米壓印於感測器之開發與應用

Abstract

本研究開發介電質加熱輔助奈米壓印製程，並用之來製造金屬奈米結構的感測器。以介電質加熱敏感聚合物溶液之旋轉塗佈方法，分別將共聚聚酯（PETG）旋塗於環聚碳酸酯（PC）基材上及聚氯乙烯（PVC）旋塗於環烯烴聚合物（COP）及玻璃基材上。置於奈米壓印工作平台，以具有奈米結構的鎳-鈷模作為母模，藉由介電質加熱之快速升溫，在幾秒鐘內即能將基材加熱，並將奈米結構圖案轉印至聚合物之旋塗膜，簡單快速壓印製作出高精度的奈米結構。接著使用直流式真空濺鍍系統將金屬薄膜披覆於轉印的奈米結構，使之成為具金屬奈米結構的感測器，應用表面電漿共振（SPR）及表面增強拉曼散射（SERS）之量測分析，驗證生物感測器及可撓性薄膜感測器的感測能力與功能性。 PETG旋塗膜於PC基材，奈米壓印製作出奈米線、奈米柱及奈米格柵等各種結構圖案。鍍金屬後利用SPR量測，銀膜奈米線結構的半高寬（FWHM）為6.01 nm，其波長靈敏度達550 nm / RIU。測試免標定的檢測透過BSA與Anti-BSA之專一性結合功能，當抗原與抗體產生交互作用，於解析度為0.02 nm的光譜儀，可檢測到的Anti-BSA生物分子濃度約0.795 nM。 PVC旋塗膜於COP及玻璃上，奈米壓印出奈米結構於不同的基材。鍍金屬後利用SPR量測，驗證BSA與Anti-BSA免標定之抗原與抗體相互作用的檢測能力。本研究也開發可撓性薄膜感測器的應用，銀膜奈米線結構於彎曲情況進行SPR量測，其角度靈敏度為0.12 °/ nm，於解析度為0.02 nm的光譜儀，可最小檢測角度約2.4 × 10-3 °。利用SERS量測，將對-硫基苯甲酸（pMBA）修飾於金膜奈米柱結構，於曲面上的奈米柱能有效地增加拉曼熱點的密度，與平面放置相比較，可在彎曲半徑6 mm的曲面提升2倍SERS訊號。本研究證實介電質加熱輔助奈米壓印用於製造高品質之生物感測器及可撓性薄膜感測器的可行性。

This study developed dielectric heating-assisted nanoimprint lithography (NIL) for fabrication of nanostructures for sensors. Two kinds of dielectric heating sensitivity polymer solution were spin-coated onto different substrates, namely, Polyethylene terephthalate glycol-modified (PETG) on polycarbonate (PC) substrate, and polyvinyl chloride (PVC) on cyclic olefin polymer (COP) and glass substrates. Using the nanoimprint process, taking advantage of rapid heating of dielectric materials, the nanostructure on the Ni-Co master mold can be replicated onto substrates in a few seconds. The nanostructure were then coated with metal thin film using DC sputtering system. The characteristics of surface plasmon resonance (SPR) and surface enhanced Raman scattering (SERS) for sensing were evaluated. For PETG spin-coated film, patterned nanostructures including nanowire, nanorod, and nanogrid arrays were successfully fabricated on PC substrate. For SPR sensing, the silver-capped nanowires achieved a full width at half maximum (FWHM) of 6.01 nm and wavelength sensitivity of 550 nm / RIU. The functionality of the sensor was verified by the specificity of label-free antigen–antibody interactions with BSA and Anti-BSA, the minimum detection biomolecules of Anti-BSA reached 0.795 nM under 0.02 nm wavelength resolution. For PVC spin-coated film, the imprinted nanowire and nanorod nanostructures on COP and glass substrates were successfully made. The functionality of the label-free antigen–antibody interactions for BSA and Anti-BSA were used to verify the sensing ability under SPR measurement. In addition, taking advantage of the flexibility of PVC, ultraflexible film sensor was developed. Using the silver-capped nanowires in the bending condition to measure SPR, the angular sensitivity was 0.12 degree/nm and the minimum detection angle was 2.4x10-3 degree under 0.02 nm wavelength resolution. In SERS sensing, the curved gold-capped nanorods immobilized by 4-mercaptobenzoic acid (pMBA) can increase the density of Raman hot spot. Under curved radius of 6 mm, enhanced SERS signal was two times of that detected using a planar SERS substrate. This study confirmed the feasibility and potential of biosensors and ultraflexible film sensors fabricated using dielectric heating-assisted nanoimprint.