Innovative flexible gold nanoparticle SERS platform fabricated by a self-assembly and rapid approach

Surface-enhanced Raman scattering (SERS) is a powerful technique for detecting chemical and biological molecules at ultra-low concentrations. Among SERS substrates, paper-based platforms have gained attention due to their low cost, portability, and ease of fabrication. However, their limited enhancement factor (EF) and detection sensitivity remain key challenges. In this study, we present a novel flexible and adhesive paper-based SERS substrate coated with gold nanoparticles (AuNPs), achieving an EF of ~10⁷ significantly surpassing many existing paper-based platforms. Our substrate demonstrates remarkable performance in biosensing applications, enabling the detection of Shiga toxin 2 (Stx2) from Escherichia coli in PBS with a detection limit (LOD) of 0.0056 nM. This ultra-low LOD outperforms many previously reported paper-based SERS sensors. Additionally, the strong adhesion properties of our substrate allow efficient sample collection via direct contact, making it highly suitable for real-world applications. Given its high sensitivity, cost-effectiveness, and ease of use, this innovative SERS platform holds great promise for rapid pathogen detection, biomedical diagnostics, and point-of-care testing.