Fig. 4

Raman reporter-induced aggregation. When high concentrations of Raman reporter were used during the reporter labeling process, nanoparticle aggregation occurred. The aggregation process results in a LSPR shift and a reduction in LSPR intensity, which can reduce SERS enhancement. DTTC iodide-induced aggregation was observed by monitoring the LSPR peak spectrum of the nanoparticles and by using dynamic light scattering