Improving Nanoprobes Using Surface-Enhanced Raman Scattering from 30-nm Hollow Gold Particles

Abstract

We report the development of nanoprobes that exploit the surface-enhanced Raman scattering (SERS) from nonaggregated, hollow, gold nanospheres (HGNSs). The homogeneity of the HGNSs leads to a nearly 10-fold improvement in signal consistency over standard silver SERS substrates, which translates into a significant increase in sensitivity and dynamic range for the model application of pH sensing. Moreover, the small size (30-nm diameter) of these SERS-active nanoparticles represents a major step in advancing sensing technology based on SERS, making this technology more amenable to intracellular sensing.

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“…There is significant signal enhancement for the HGNs. Furthermore, all the peak intensity ratios for the HGNs fall within 0.9 and 1.1 [290]. This represents a statistical distribution of 5%.…”

“…When Schwartzberg et al compared HGNs to silver aggregates, the Rayleigh scattering intensity of HGNs showed nearly a 10-fold improvement over Ag [290]. Fig.…”

“…For HGNs the intensity ratios ranged from 0.8 to 1.4 compared to 0.9 to 3.1 for Ag. Both Schwartzberg and Lee attribute the enhancement of the Raman signal and consistency of intensity ratios to the uniform structure and narrow plasmon dispersity of HGNs [287,290].…”

“…It has been reported that HGNs show improved SERS activity when compared to Ag aggregates [287,290,291]. When Schwartzberg et al compared HGNs to silver aggregates, the Rayleigh scattering intensity of HGNs showed nearly a 10-fold improvement over Ag [290].…”

“…In contrast, the Ag NPs exhibit a 45% statistical distribution (0.5-1.7) with respect to consistency. This inconsistency is due to the randomness of aggregation which, depending on size and shape, will produce variation in the EM field associated with the ensemble [64,65,[288][289][290].…”