Design and performance of pH-responsive cyano-Raman label SERS probes based on single urchin Au nanoparticles.

A cyano-Raman label pH-responsive SERS probe was constructed by immobilizing 6-MPN molecules onto the surface of a single urchin Au nanoparticle (AuNP). The effects of different conditions on the synthetic materials were investigated and the optical properties of the single nanoparticles were evaluated. The peak-strength ratio of SERS probes at 1589 cm -1 and 2240 cm -1 exhibited a linear relationship in the pH range 4-7. The properties and stability of the probe were also verified by the acid-base cycle and ion interference tests.