Single gold nanostars enhance Raman scattering

Raman scattering from single gold nanostars coated with self-assembled monolayers of 4-mercaptobenzoic acid is observed. The Raman signal can be detected without the need of forming particle aggregates or resonant electronic excitation of the analyte. A total Raman enhancement factor of 10(7) for individual nanostars is estimated. These features make gold nanostars promising for Raman imaging in cells or cellular membranes.