雷射誘發材料轉移於非酶式低濃度葡萄糖檢測之研究

Abstract

雷射誘發材料轉移(Laser-induced forward transfer, LIFT)為一精密數位印刷技術，使用脈衝雷射將金屬或生物材料等薄膜(Donor)局部轉移至接收基板(Receiver)上以達到高精度及高分辨率之印刷效果。LIFT以非接觸加工的性質消除了噴嘴阻塞的風險並可自由設計轉印圖案，其快速製造的能力非常契合微型生物感測器的製造需求，不僅具備低成本的優點同時不降低其靈敏度。 近年來葡萄糖檢測在臨床診斷、食品工業之研究日益增多，在葡萄糖感測器的製造中，葡萄糖電化學氧化的催化劑至關重要，感測材料包括貴金屬（Au, Pt等）、金屬合金（PtPd、PtRu等）、金屬氧化物(ZnO, CuO, NiO 等)非酵素修飾的葡萄糖感測電極被大量研究。而銅基材料相比貴金屬擁有更高的靈敏度以及更低的成本，其金屬氧化物CuO、Cu2O更是對葡萄糖表現出出色的催化活性。傳統氧化銅薄膜的備製常使用化學氣相沉積(Chemical Vapor Deposition, CVD)、熱氧化或是磁控濺射等，但這些方法通常需要較長的處理時間且涉及繁雜化學過程。相較之下雷射誘發材料轉移能夠提供快速且可控的加工製造功能性微/奈米結構，能夠有效增加接觸表面積及提升電化學活性位點。 本研究首先利用雷射將固定在玻璃上之銅薄膜(1000 nm)分別轉移圖案於氧化銦錫(ITO)以及聚對苯二甲酸乙二酯(PET)基板上，其雷射參數如能量密度、供體受體間距、掃描速度及轉印環境皆會大幅影響印刷品質。考量轉移後的形貌、導電性及附著力後在不損害基板的情形下轉移尺寸5 mm × 10 mm圖案於基板上。轉移於ITO以及PET基板作為工作電極，並搭配商用的氯化銀參考電極 (Ag/AgCl)及輔助電極鉑(Pt)。透過場發射掃描式電子顯微鏡觀察轉移於不同基板上之薄膜形貌，並利用X-ray繞射儀觀察到轉印後所有基板皆產生了Cu2O成份。由於雷射誘發材料轉移製程於可撓性基板上之電性不甚理想，本研究也可在計時安培法電位優化的結果觀察到，不論電位為何，PET電極之靈敏度表現皆略低於ITO電極，但同時可以觀察到的是兩者在(0.003 mM – 0.4 mM)線性範圍下皆展現了優異的葡萄糖檢測性能。Cu2O/ITO電極之靈敏度約為1214.33 μAmM-1 cm-2，偵測極限為 1.2968 μM，其電流與葡萄糖濃度之線性關係為(R2 = 0.989)，而Cu2O/PET電極其靈敏度約為 1188.14 μAmM-1 cm-2，偵測極限為 1.824 μM，其電流與葡萄糖濃度之線性關係為(R2 = 0.997)，並且兩種電極在抗壞血酸(Ascorbic acid)、尿酸(Uric acid)、多巴胺(Dopamine)、氯化鈉(NaCl)等干擾物存在的情形下，仍對葡萄糖具有良好的選擇性。

Laser-induced forward transfer (LIFT) is a high-precision digital printing technique that utilizes pulsed lasers to transfer thin films (Donors) of metals or biomaterials onto a receiving substrate (Receiver) in order to achieve high-resolution printing results. LIFT is a non-contact technique that eliminates the risk of nozzle clogging and allows for the free design of transfer patterns. Its rapid manufacturing capability is well-suited for the fabrication of micro-biosensors, offering not only low-cost advantages but also maintaining high sensitivity. In recent years, glucose detection has been a growing interest in both clinical diagnostics and food industry research. In the fabrication of glucose sensors, the role of catalysts for the electrochemical oxidation of glucose is of crucial importance. Sensing materials include noble metals (e.g., gold, platinum), metal alloys (e.g., platinum-palladium, platinum-rhodium), and metal oxides (e.g., zinc oxide, copper oxide, nickel oxide). Non-enzymatic modification of glucose sensing electrodes has been the subject of extensive study. Copper-based materials exhibit higher sensitivity and lower cost compared to noble metals, and their metal oxides, CuO and Cu2O, demonstrate excellent catalytic activity for glucose. The preparation of copper oxide thin films typically employs chemical vapour deposition (CVD), thermal oxidation, or magnetron sputtering. However, these methods typically require lengthy processing times and entail complex chemical processes. In contrast, laser-induced forward transfer (LIFT) offers a rapid and controllable method of fabricating functional micro/nano structures, which effectively increases the contact surface area and enhances electrochemical active sites. In this study, laser-induced forward transfer (LIFT) was employed to transfer copper thin films (1000 nm) deposited on glass substrates onto both PET and ITO substrates. The quality of the printed material is significantly influenced by the laser parameters, including energy density (J/cm²), donor-receiver gap (µm), scanning speed (mm/s), and the transfer environment. Consequently, in order to ensure the morphology, conductivity, and adhesion of the transferred patterns were not compromised, 5 mm × 10 mm patterns were transferred onto the substrates without damaging them. The transferred patterns on ITO and PET substrates served as working electrodes, paired with a commercial silver/silver chloride reference electrode (Ag/AgCl) and a platinum (Pt) auxiliary electrode. The morphology of the transferred patterns on different substrates was initially examined using field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD) analysis revealed the formation of Cu₂O in both cases. While the LIFT process yielded less than optimal results on flexible substrates, chronoamperometry optimisation results indicated that, regardless of the potential, the sensitivity of the PET electrode was slightly lower than that of the ITO electrode. Nevertheless, both electrodes demonstrated excellent glucose detection capabilities within a linear range of 0.003 mM to 0.4 mM. The sensitivity of the Cu2O/ITO electrode was 1214.33 μAmM⁻¹ cm⁻² (R² = 0.989), with a limit of detection (LOD) of 1.2968 μM. For the Cu2O/PET electrode, the sensitivity was 1188.14 μAmM⁻¹ cm⁻² (R² = 0.997), with a LOD of 1.824 μM. Moreover, both electrodes exhibited excellent selectivity for glucose in the presence of potential interferents, including ascorbic acid (AA), uric acid (UA), dopamine (DA), and sodium chloride (NaCl). These tests were instrumental in elucidating the characteristics of the working electrodes and providing substantial evidence in support of their application in glucose detection.