Design and fabrication of pH-responsive monodisperse gold/peptide/gold sandwich nanoparticles

Abstract

Integrating stimuli-responsive molecules and plasmonic nanoparticles into a single nanoscale platform for stimuli-adaptive functionality is of great importance in nanotechnology. However, existing strategies for constructing stimuli-responsive molecule/noble metal composite nanoparticles based on a solution or solid-phase methods result in limited separation efficiency and low structural precision. Here, we propose a solid-solution combined strategy to prepare monodisperse pH-adaptive gold/peptide/gold sandwich nanoparticles with precisely controlled layered structures. Wafer-scale gold/peptide/gold layered structure was first deposited on a silicon wafer and then etched by argon plasma using silica nanoparticles as a mask. Sandwich nanoparticles can be easily released from silicon wafers by a wet etching reaction and then purified by centrifugation. The as-prepared gold/peptide/gold nanoparticles exhibit distinct localized surface plasmon resonance (LSPR) coupling peaks at near-infrared wavelengths in acidic and neutral environments, demonstrating their great potential as pH-responsive optical nanodevices. In addition, this flexible and configurable approach enables the precise fabrication of layered nanostructures of different sizes, layer numbers, and compositions, with wide applications in optical actuation and sensors.