Inkjet-printed AG micro-/nanostructure clusters on CU substrates for in-situ pre-concentration and surface-enhanced Raman scattering

Here, we describe a novel method for SERS substrates using inkjet printing that allows AgNO
₃
solution to be regularly injected onto a superhydrophobically functionalized Cu substrate. The chemical replacement reaction occurs only within droplet-injected areas, creating a hydrophilic Ag micro-/nanostructures and a wettability gradient on the Cu surface. As a sample drop containing analytes and Au nanoparticles (Au-NPs) evaporates on the Cu substrate, the analytes and Au-NPs are delivered to the hydrophilic Ag nanoplate array (Ag-NPA), facilitating simple, easy, and in-situ pre-concentration and sensitive SERS detection. Our approach made it possible to successfully detect antibiotics at very low concentrations, thereby demonstrating a remarkable potential of the inkjet printing method for SERS substrates.