Target induced interfacial self-assembly of nanoparticles: A new platform for reproducible quantification of copper...

One of the main problems of the nanoparticle dispersion state change (e.g. from dispersion to aggregation) based surface-enhanced Raman scattering (SERS) detection is that the dynamic process of such in-solution reactions is always uncontrollable. This leads to poor reproducibility from a narrow time window of all such strategies, and finally great difference between the data from the diverse methods, and even between various sample batches. To address such problem, a facile, rapid SERS quantification protocol has been developed relying on target induced nanoparticle self-assembly at oil/water interfaces for copper ions analysis. In response to copper, the core-molecule-shell (CMS) nanoparticles spontaneously migrate to the interface and are assembled into densely packed arrays generating strong plasmonic coupling, which enables stable, sensitive and selective Raman quantitation, as well as visual detection. Also, this strategy shows capability for determination of large scale samples as the products can be stable for at least three weeks, and has been successfully applied to real sample detection. The developed Target Induced Nanoparticle Self-Assembled Interface (TINSAI) can be employed to both visual test and Raman quantitative detection, which would provide a platform for on-site screening as well as high-throughput detection with high sensitivity and selectivity.