Combined Surface-Enhanced Raman Scattering Emissions for High-Throughput Optical Labels on Micrometer-Scale Objects

High-throughput optical labeling technologies have become increasingly important with the growing demands for molecular detection, disease diagnosis, and drug discovery. In this thought, a series of CN-bridged coordination polymer encapsulated gold nanoparticles have been developed as a universal and interference-free optical label through a facile and auxiliary agent-free self-assembly route. Moreover, surface-enhanced Raman scattering (SERS) emissions of CN-bridge can be tuned flexibly by simple replacement of Fe²⁺/Fe³⁺ with other metal ions relying on the synthesis of three Prussian blue analogues encapsulated gold nanoparticles (Au@PBA NPs). Thus, three distinct Raman frequencies have been acquired, which merely replaced the metal irons. On the basis of the potential supermultiplex optical label, space-confined surface-enhanced Raman scattering (SERS) emissions have been realized. Relying on "Abbe theorem", the focused laser allows the pure and single triple bond-coded SERS emissions to be combined into a unique and independent output, so-called "combined SERS emission" (c-SERS), if the Au@PBA NPs were confined into one micrometer-scale object. This study demonstrated c-SERS may simultaneously provide 2 - 1 optical labels only using n single emissions in the Raman-silent region for micrometer-size objects.