Research Unit for Clean Technology, Indonesian Institute of Sciences, Bandung 40135, Indonesia.
International Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal.
ACS Biomater Sci Eng. 2020 May 11;6(5):3122-3131. doi: 10.1021/acsbiomaterials.9b01890. Epub 2020 Apr 24.
In this present work, a plasmonic sensor is developed through an extremely cheap cellulose-based source, widely known as a food product, nata de coco (NDC). Capturing its interesting features, such as innate surface roughness from naturally grown cellulose during its fermentation period, the engineering and modulation of NDC fibril size and properties were attempted through a high-pressure homogenization (HPH) treatment to obtain highly dense nanofibrils. After the transformation into a thin, paper-sheet form through a casting process, the homogenized bacterial cellulose (HBC) resulting from HPH was compared with the normally agitated bacterial cellulose (BC) pulp and decorated with silver nanoparticles (AgNPs) to produce plasmonic papers, for further application as surface-enhanced Raman scattering (SERS) substrate. As demonstrated in the measurement of Rhodamine 6G (R6G) molecule, the plasmonic HBC paper sheet provided more prominent SERS signals than the plasmonic BC due to its high surface roughness and improved textural properties from the nanofibrillation process favoring better adsorption of AgNPs and effective SERS hotspots generation. The plasmonic HBC obtained a 2 order higher estimated SERS enhancement factor over the plasmonic BC with a limit of detection of approximately 92 fM. Results denote that the proposed approach provides a new, green-synthesis route toward the exploration of biodegradable sources integrated into an inexpensive and simple nanostructuring process for the production of flexible, paper-based, plasmonic sensors.
在本工作中，通过一种极其廉价的纤维素来源——广为人知的食品椰纤果（NDC）——开发了一种等离子体传感器。利用其独特的特性，如在发酵过程中天然生长的纤维素所具有的固有表面粗糙度，通过高压均质处理（HPH）尝试对 NDC 原纤尺寸和性能进行工程化和调节，以获得高密度的纳米原纤。通过浇铸工艺将其转化为薄的片状形式后，将 HPH 产生的均化细菌纤维素（HBC）与通常搅拌的细菌纤维素（BC）纸浆进行比较，并进行银纳米粒子（AgNPs）修饰，以制备等离子体纸，进一步用作表面增强拉曼散射（SERS）基底。如对 Rhodamine 6G（R6G）分子的测量所示，由于高表面粗糙度和纳米纤维化过程改善的结构特性有利于更好地吸附 AgNPs 和有效产生 SERS 热点，等离子体 HBC 纸比等离子体 BC 提供了更显著的 SERS 信号。与等离子体 BC 相比，等离子体 HBC 的估计 SERS 增强因子高 2 个数量级，检测限约为 92 fM。结果表明，该方法提供了一种新的绿色合成途径，用于探索可生物降解的资源，并整合到廉价且简单的纳米结构工艺中，以生产灵活的基于纸张的等离子体传感器。
