Facile synthesis of Ag@Au core-satellite nanowires for highly sensitive SERS detection for tropane alkaloids

Abstract

Compared with silver nanoparticles, gold nanoparticles have excellent chemical resistance and biocompatibility, while silver nanoparticles have more excellent local surface plasmon resonance characteristics than gold. In this article, we developed a simple method for growing island-shaped gold nanoparticles on the surface of silver nanowires (NWs), so that the prepared Ag@Au NWs have both the advantages of Au and Ag without their disadvantages. Furthermore, by changing the reaction parameters, we achieved the regulation of the density of island-shaped gold nanoparticles on the Ag NWs surface, thereby optimizing its LSPR performance. We use the prepared Ag@Au NWs as the base material for highly sensitive Surface enhanced Raman scattering (SERS) detection. By using 4-aminothiophenol (4-ATP) as the test molecule to explore the uniformity of the prepared SERS substrate, the detection limit of 4-ATP reached 10-9 M. And 10 points were randomly selected for testing and the RSD was 7.4%, indicating the Ag@Au NWs SERS substrates had excellent uniformity. Furthermore, we have achieved highly sensitive SERS detection of 5 tropane alkaloids including L-Hyoscyamine, Anisodamine, Scopolamine Hydrobromide, scopolamine methyl bromide and scopolamine butyrate bromide. The limit of detection is 10-9 M, 10-10 M, 10-9 M, 10-9 M and 10-10 M. Furthermore, by analyzing the obtained SERS spectra, we realized the differentiation of 5 kinds of tropane alkaloids by their characteristic peaks.