Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
ACS Appl Mater Interfaces. 2020 Jun 10;12(23):25616-25624. doi: 10.1021/acsami.0c05379. Epub 2020 May 29.
A novel strategy to functionalize transparent flexible plastic films with an optical ion-sensing layer using an inkjet-printing technology is described. The hydrophobic sensing chemicals that include a sodium ionophore, a lipophilic proton chromoionophore, and a lipophilic ion-exchanger are co-deposited onto substrates such as transparent polyester film sheets in the absence of any plasticizer and/or hydrophobic polymer matrix. The inkjet-printing process enables the formation of optode films with nanoscale thickness/roughness that readily facilitate interfacing with aqueous samples. Using a smartphone detector, the colorimetric response of the optodes is shown to reach 95% of equilibrium values within 100 s in response to different concentrations of sodium ions, which is more rapid than traditional ion-selective optodes based on plasticized PVC films as the sensing layer. The new optodes also exhibit high selectivity to Na over interfering ions including K, Ca, and Mg. Chemical leaching experiments show that the highly hydrophobic optode components remain in place on the plastic substrate surface. Hence, excellent sensor stability and fully reversible optical responses are obtained, which is essential for potential continuous monitoring applications. Further testing of the sensors with undiluted human sweat samples is shown to yield accurate values for sodium concentrations. Therefore, the use of plasticizer-free ion-selective optode nanolayers that enable highly selective ion sensing on a clear plastic support is likely to expand the range of available chemical sensors suited for preparing wearable real-time sweat analysis devices.
本文介绍了一种在透明柔性塑料薄膜上利用喷墨打印技术功能化光学离子传感层的新策略。包括钠离子载体、亲脂质子显色离子载体和亲脂离子交换剂在内的疏水性传感化学品在没有任何增塑剂和/或疏水性聚合物基质的情况下共同沉积在透明聚酯薄膜等基底上。喷墨打印工艺能够形成具有纳米级厚度/粗糙度的光学生物传感器薄膜，便于与水相样品进行界面作用。使用智能手机检测器，显色光学生物传感器的比色响应显示，在 100 s 内即可达到不同钠离子浓度的 95%平衡值，这比基于增塑 PVC 薄膜作为传感层的传统离子选择性光学生物传感器更快。新型光学生物传感器对 Na 也表现出高选择性，对 K、Ca 和 Mg 等干扰离子的选择性较低。化学浸出实验表明，高度疏水性的光学生物传感器组件仍保留在塑料基底表面。因此，获得了出色的传感器稳定性和完全可逆的光学响应，这对于潜在的连续监测应用至关重要。进一步对未经稀释的人体汗液样本进行传感器测试，结果表明，钠离子浓度的测量值准确。因此，在透明塑料支撑物上使用无需增塑剂的离子选择性光学生物传感器纳米层来实现高选择性离子传感，有望扩展适用于制备可穿戴实时汗液分析设备的化学传感器的范围。
