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[摘要]：We report a new class of turn-on surface enhanced Raman scattering (SEAS) sensors for the sensitive and selective detection of cadmium ion (Cd(2+)) by taking advantage of the interparticle plasmonic coupling generated in the process of Cd(2+)-selective nanoparticle self-aggregation. The SERS-active nanoparticles consist of 41-nm gold nanoparticles, encoded with a Raman-active dye through a disulfide anchoring group, and a layer of Cd(2+)-chelating polymer brush coating grafted on the nanoparticle via surface-initiated atom transfer radical polymerization. These SERS nanoparticles are optimized to remain spectrally silent when staying as single particles. Addition of Cd(2+) leads to interparticle self-aggregation and immediately turns on the SEAS fingerprint signal with up to 90-fold of signal enhancement. The selectivity of the SERS nanoparticle for Cd(2+) was also examined, showing that various common metal ions cannot induce interparticle self-aggregation and the turn-on of SERS signal. In contrast to nanoparticle-based colorimetric assays, the SERS probe is also capable of detecting Cd(2+) in heavily colored samples. |
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