Silica/Nanographene Oxide Nanocomposites Decorated With Au@Ag Nanoparticles as Surface-Enhanced Raman Scattering Tags for Highly Sensitive Quantitative Lateral Flow Immunoassays

초록

Surface-enhanced Raman scattering-based lateral flow immunoassay (SERS-LFIA) has been explored as a sensitive, quantitative platform for liquid biopsy biomarker detection. Graphene oxide (GO) is promising for SERS signal enhancement, but its sheet-like structure reduces particle mobility and signal reproducibility, limiting its use as an LFIA tagging material. Herein, silica (SiO2)/nanographene oxide (nGO) nanocomposites (SGO) decorated with Au@Ag nanoparticles (SGO@Au@Ag NPs) were prepared by attaching nGO onto SiO2 NPs, followed by the growth of Au@Ag NPs. By introducing smaller-sized nGO onto SiO2 NPs, GO-induced aggregation was effectively suppressed, and the controlled growth of Au@Ag NPs generated interparticle nanogaps on the nanocomposite surface. SGO@Au@Ag NPs exhibited uniform and strong SERS activity mainly through the electromagnetic enhancement of Au@Ag NPs, with an additional contribution from nGO-related charge-transfer effects, while distinct signals across various Raman labeling compounds confirmed their applicability as SERS tags. In SERS-LFIA, SGO@Au@Ag NPs outperformed SiO2@Au@Ag and SiO2@Au@Au NPs, detecting prostate-specific antigen and carbohydrate antigen 19-9 at 9.4 & times; 104- and 1.2 & times; 102-fold lower concentrations, respectively. This study presents a promising application of SGO@Au@Ag NPs as SGO-based SERS tags in LFIA, suggesting their potential for extension to multiplexed detection platforms based on sensitive biomarker analysis and clinical sample applicability.

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