Fluorescence and Scattering Dual-Mode Multiplexed Imaging with Gold–Silver Alloy Core Silica Shell Nanoparticles

Gold–silver alloy core silica shell nanoparticles (Au/Ag@SiO2 NPs) with fully accordable photophysical properties were developed and used as contrast agent for multiplexed cell-imaging applications. Using a seed growth strategy, these nanoparticular labels can be designed to suit specific experimental needs and be clearly identified based on their distinctive combination of scattering and fluorescence colors. In this Article, the multiplexed cell-imaging capabilities of Au/Ag@SiO2 NPs are presented using four different combinations of core composition and fluorescence colors. In a proof of concept experiment, 86% of total nanoparticles were correctly identified by an optical microscope with a system offering fluorescence and darkfield detection capabilities. This multiplatform identification strategy was successfully applied for the detection of four different nanoparticular architectures in cell-imaging experiments.