Transfer Printing Assisted Fabrication of a Cicada Wing Inspired Nanopaper SERS Platform

Because of the ultrasmooth surface and high optical transparence nanostructure, nanofibrillated cellulose paper (nanopaper) has been thinking as a promising substrate material for various areas, particularly in the highly sensitive detection technique, surface-enhanced Raman scattering (SERS). Conventional SERS detection typically relies on substrates with two-dimensional structures, which are often unsuitable for analytes with low adsorption capacity. In contrast, the surface architectures found in plants and animals possess distinctive three-dimensional micro/nanostructures that can generate abundant electromagnetic hot spots, offering a bioinspired strategy for enhancing SERS signals. In this work, we develope a cicada-wing-inspired nanopaper SERS platform via an integrated transfer-printing-assisted fabrication method. Electromagnetic simulations confirmed that the replicated nanostructures facilitated hot spot formation and improved the interaction between plasmonic nanoparticles and analyte molecules. Using Rhodamine 6G (R6G) as the SERS example, the substrate achieved an exceptionally low limit of detection (286 fM) and a high enhancement factor (1.09 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup>). These results demonstrate that the proposed fabrication strategy enables practical, high-performance nanopaper-based biomimetic SERS substrates.