Bimetallic nanoparticles: towards selective analysis of phosphorylated compounds by surface-enhanced Raman spectroscopy

The selective detection of phosphorylated molecules is crucial for various biochemical and analytical applications, yet remains challenging due to their weak Raman signals and limited interactions with conventional SERS substrates. This study presents a novel synthesis strategy for bimetallic Ag/Fe<i>_x</i>O<i>_y</i>nanocomposites with ambition for the improved sensitivity and selectivity of SERS detection for phosphorylated compounds. Our approach successfully integrates alkaline precipitation of iron salts with the reduction of silver cations, overcoming the inherent incompatibility of these processes to produce a stable colloid. The resulting nanocomposites feature an architecture that ensures direct analyte interaction with both components: iron oxides selectively capture phosphorylated molecules, while silver provides plasmonic enhancement of the Raman signal. Our findings highlight the critical role of the silver/iron oxides interface in governing SERS sensitivity. This work represents a significant step toward more effective SERS-based detection strategies, with potential applications in real-time analysis using flow-based systems, such as online monitoring after separation techniques in biochemical and medical fields.