Mohan Aiswarya, Chandran Lekshmi, Veena Lalan, Devi Chandra Ramachandrapanicker, Gopchandran Kunnel Gopalan
Department of Optoelectronics, University of Kerala, Kariavattom, Thiruvananthapuram, Kerala 695581, India.
School of Communication Sciences and Technology, APJ Abdul Kalam Technological University, Thiruvananthapuram 695016, India.
Langmuir. 2025 Jul 15;41(27):17633-17643. doi: 10.1021/acs.langmuir.5c01229. Epub 2025 Jul 2.
This study introduces a flexible and cost-effective surface-enhanced Raman scattering (SERS) substrate incorporating surface-modified silver nanowires (AgNWs) and sandpaper-assisted soft lithography. AgNWs were chemically roughened to enhance surface roughness, thereby increasing the density of SERS-active hotspots. The modified AgNWs were then embedded into a polydimethylsiloxane (PDMS) matrix to form a hybrid SERS substrate (SMAW) with enhanced mechanical flexibility, stability, and signal reproducibility. The sandpaper-templated PDMS surface further contributed to SERS performance by introducing microstructures that amplified localized electromagnetic fields and improved molecular adsorption. The developed SMAW hybrid substrate exhibited outstanding SERS sensitivity, achieving analytical enhancement factors of 10 for crystal violet (CV) and 10 for malachite green (MG), with nanomolar-level detection limits. Raman mapping and point-to-point measurements demonstrated uniform signal distribution across the substrate, while long-term stability tests over 60 days revealed minimal signal variation (RSD = 3.68%), ensuring consistent analytical performance. Furthermore, PDMS encapsulation prevented AgNW oxidation, significantly improving substrate durability. Designed for practical applications, this flexible SERS substrate enables direct and nondestructive detection of fishery drug residues from aquatic product surfaces via surface swab sampling. By integrating nanomaterial surface engineering, microstructured polymer substrates, and analytical sensing, this study provides a highly sensitive and reproducible method for real-world food safety monitoring.
本研究介绍了一种灵活且经济高效的表面增强拉曼散射（SERS）基底，该基底结合了表面改性的银纳米线（AgNWs）和砂纸辅助软光刻技术。对AgNWs进行化学粗糙化处理以提高表面粗糙度，从而增加SERS活性热点的密度。然后将改性后的AgNWs嵌入聚二甲基硅氧烷（PDMS）基质中，形成具有增强的机械柔韧性、稳定性和信号重现性的混合SERS基底（SMAW）。砂纸模板化的PDMS表面通过引入放大局部电磁场并改善分子吸附的微观结构，进一步提高了SERS性能。所开发的SMAW混合基底表现出出色的SERS灵敏度，结晶紫（CV）和孔雀石绿（MG）的分析增强因子均达到10 ，检测限为纳摩尔级。拉曼映射和点对点测量表明整个基底上信号分布均匀，而超过60天的长期稳定性测试显示信号变化极小（相对标准偏差RSD = 3.68%），确保了一致的分析性能。此外，PDMS封装可防止AgNW氧化，显著提高了基底的耐用性。这种灵活的SERS基底专为实际应用而设计，通过表面擦拭采样能够直接且无损地检测水产品表面的渔药残留。通过整合纳米材料表面工程、微结构化聚合物基底和分析传感技术，本研究为实际食品安全监测提供了一种高度灵敏且可重现的方法。
