Lee Chien-Wei, Chia Zi Chun, Hsieh Yi-Ting, Tsai Hsiao-Chieh, Tai Yenpo, Yu Teng-To, Huang Chih-Chia
Department of Photonics, Center of Applied Nanomedicine, Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan70101, Taiwan.
Department of Chemistry, Soochow University, Taipei 11102, Taiwan.
Nanoscale. 2021 Feb 25;13(7):3991-3999. doi: 10.1039/d0nr06537d.
A two-dimensional flexible surface-enhanced Raman scattering (SERS) filter substrate provides an alternative strategy for the highly sensitive portable detection of various toxic molecules and biomaterials. Herein, we developed a solid-liquid interfacial reduction reaction to post-engineer a solid Au nanostructure surface on filter paper to improve the SERS effect. Among four reductants (ascorbic acid, l-dopamine, hydroquinone (HQ), and formaldehyde), HQ possessed a larger oxidation overpotential and facilitated homogeneous growth, forming small Au branch-structure nanoparticles from HAuCl4 solution. Due to the surface effect by exposing abundant -OH groups and intrinsic aromatic rings from TNA/HQ on nano-gold, the SERS effect on positively charged analytes near the plasmonic Au surface was enhanced, while forming a protective layer against severe water interruption. The resulting SERS substrate with branched nano-gold provided several SERS-enhanced sites, increased the enhancement by more than 6 times compared to original SERS sensing, and displayed a 1.4-7.4 × 105 analytical enhancement factor, which leads to a limit of detection down to several ppb. Less than 6% of deviation in the SERS intensity at different sensing sites was observed. We successfully improved the primary SERS substrate using a high overpotential reductant. Owing to its soft and flexible properties, the paper-based SERS substrate can be used conveniently in different sizes, pasting on curved materials, detecting additives in fish, and preventing the coffee-ring effect, showing high practicality and potential commercial value in the future.
二维柔性表面增强拉曼散射（SERS）滤光片基板为各种有毒分子和生物材料的高灵敏度便携式检测提供了一种替代策略。在此，我们开发了一种固液界面还原反应，对滤纸表面的固态金纳米结构进行后处理，以提高SERS效应。在四种还原剂（抗坏血酸、左旋多巴胺、对苯二酚（HQ）和甲醛）中，HQ具有较大的氧化过电位，并促进均匀生长，从HAuCl4溶液中形成小的金分支结构纳米颗粒。由于纳米金表面暴露了大量来自TNA/HQ的-OH基团和固有芳香环所产生的表面效应，增强了等离子体金表面附近带正电分析物的SERS效应，同时形成了一层防止严重水中断的保护层。所得的带有分支纳米金的SERS基板提供了多个SERS增强位点，与原始SERS传感相比，增强倍数增加了6倍以上，并显示出1.4 - 7.4×105的分析增强因子，检测限低至几ppb。在不同传感位点观察到SERS强度的偏差小于6%。我们成功地使用高过电位还原剂改进了原始的SERS基板。由于其柔软和灵活的特性，纸质SERS基板可以方便地用于不同尺寸，粘贴在弯曲材料上，检测鱼类中的添加剂，并防止咖啡环效应，在未来显示出很高的实用性和潜在的商业价值。
