Synthesis and SERS properties of Au@Au and Au@Ag nanomatryoshkas with embedded reporters

The widespread use of SERS for bioimaging led to the development of the novel types of labels called SERS tags. SERS tags based on a metal core with adsorbed Raman reporters and coated with one or more metal shells are called nanomatryoshkas. In this work we investigated nanomatryoshkas based on gold nanorods coated by 4-nitrobenzenethiol Raman reporter molecules with gold and silver shell (AuNRs@NBT@Au and AuNRs@NBT@Ag, respectively). By changing the conditions of synthesis we can regulate the presence or absence of a gap inside the gold nanomatryoshkas. Moreover, it was found that for these particles the SERS enhancement factor does not depend on the presence of a gap, for both cases enhancement factor is about 4×105. For nanomatryoshkas with a silver shell, it was found that the absence of a visible gap is a feature of these particles, in good agreement with the literature data.