Fabrication of Highly Rough Ag Nanobud Substrates and Surface-Enhanced Raman Scattering of λ-DNA Molecules

Raman scattering signals can be enhanced by several orders of magnitude on surface-enhanced Raman scattering (SERS) substrates made from noble metal nanostructures. Some SERS substrates are even able to detect single-molecule Raman signals. A novel silver nanobud (AgNB) substrate with superior SERS activity was fabricated with a solid-state ionics method. The AgNB substrate was formed by tightly collocated unidirectional 100 nm size silver buds, presenting a highly rough surface topography. Distinct SERS signals of single λ-DNA molecules in water were detected on AgNB substrates. AgNB substrates were compared with disordered silver nanowire (AgNW) substrates manufactured by the same method through the SERS detection of λ-DNA solutions. This original AgNB substrate provides a reliable approach towards trace analysis of biomacromolecules and promotes the utilization of the SERS technique in biomedical research.