Department of Electrical and Computer Engineering, National University of Singapore , 4 Engineering Drive 3, 117576, Singapore.
Data Storage Institute, (A*STAR) Agency for Science Technology and Research , 2 Fusionopolis Way, 138634, Singapore.
ACS Appl Mater Interfaces. 2017 Aug 9;9(31):26341-26349. doi: 10.1021/acsami.7b06669. Epub 2017 Jul 25.
Surface-enhanced Raman scattering (SERS) spectroscopy affords a rapid, highly sensitive, and nondestructive approach for label-free and fingerprint diagnosis of a wide range of chemicals. It is of great significance to develop large-area, uniform, and environmentally friendly SERS substrates for in situ identification of analytes on complex topological surfaces. In this work, we demonstrate a biodegradable flexible SERS film via irreversibly and longitudinally stretching metal deposited biocompatible poly(ε-caprolactone) film. This composite film after stretching shows surprising phenomena: three-dimensional and periodic wave-shaped microribbons array embedded with a high density of nanogaps functioning as hot-spots at an average gap size of 20 nm and nanogrooves array along the stretching direction. The stretched polymer surface plasmon resonance film gives rise to more than 10 times signal enhancement in comparison with that of the unstretched composite film. Furthermore, the SERS signals with high uniformity exhibit good temperature stability. The polymer SPR film with excellent flexibility and transparency can be conformally attached onto arbitrary nonplanar surfaces for in situ detection of various chemicals. Our results pave a new way for next-generation flexible SERS detection means, as well as enabling its huge potentials toward green wearable devices for point-of-care diagnostics.
表面增强拉曼散射（SERS）光谱学提供了一种快速、高灵敏度和非破坏性的方法，可用于对广泛的化学物质进行无标记和指纹诊断。开发大面积、均匀和环保的 SERS 基底对于在复杂拓扑表面上原位识别分析物具有重要意义。在这项工作中，我们通过不可逆和纵向拉伸沉积在金属上的生物相容性聚（ε-己内酯）薄膜来展示一种可生物降解的柔性 SERS 薄膜。这种复合薄膜拉伸后显示出惊人的现象：三维周期性波纹状微带阵列嵌入具有高密度纳米间隙的热点，平均间隙尺寸为 20nm，纳米凹槽阵列沿着拉伸方向。与未拉伸的复合薄膜相比，拉伸后的聚合物表面等离子体激元共振薄膜的信号增强了 10 多倍。此外，具有高均匀性的 SERS 信号表现出良好的温度稳定性。具有优异柔韧性和透明度的聚合物 SPR 薄膜可以贴合到任意非平面表面上，用于原位检测各种化学物质。我们的结果为下一代柔性 SERS 检测手段铺平了道路，并为绿色可穿戴设备在即时诊断方面的巨大潜力提供了可能。
