Multiple cooperative amplification paper SERS aptasensor based on AuNPs/3D succulent-like silver for okadaic acid quantization

Abstract Okadaic acid (OA) is the main toxic component of diarrhetic shellfish poisoning, which can cause vomiting, diarrhea, and even induce tumor formation in people who accidentally ingest it. To strengthen the front-end prevention and control of shellfish safety, a surface-enhanced Raman scattering (SERS) paper swab based on high-affinity binding and high-specific recognition performance of nucleic acid aptamer was proposed to detect OA by virtue of enhanced multistage plasmon coupling effect. Composite resonance bilayer constituted by evenly dispersed gold nanoparticles integrating with a three-dimensional (3D) succulent-like silver particle was facilely manufactured in-situ on the paper substrate. Subsequently, with the assistance of 3D nanotopography structured silver nano-octahedra connected on the signal probe, a multistage SERS signal cooperative amplification platform was formed with about 10-fold enhanced Raman intensity higher than either single-layer substrate. Owning to the unique strategy of superimposed signal enhancement, such paper SERS aptasensor possessed admirable specific recognition and sensitivity has been successfully used in the on-site quantization of OA, with a detection limit of 0.31 ng/mL. Furthermore, the construction of the SERS paper swab is of great significance to the promotion of rapid on-site analysis approach of OA content in seafood by customs, seafood market supervision departments and ordinary consumers.