Gold nanoflowers as efficient hosts for SERS based sensing and bio-imaging

Abstract

Intrinsically rich in hot spots, anisotropic gold nanostructures have been explored as efficient hosts for Surface Enhanced Raman Scattering (SERS). Limited toxicity, shape/size tunability and high stability of gold nanostructures makes them a better choice to be used as SERS tags compared to other plasmonic metals. In this article, gold nanoflowers using ‘green’ L-ascorbic acid have been synthesized and used as SERS tags to detect low concentrations of Rhodamine 6 G dye. It is found that the gold nanoflowers can detect the presence of R6G molecules up to 10−10 M. The nanoflower (AuNf) petals play an important role in Raman signal enhancement allowing signal improvement of the order of 106. This enhancement can be explained in terms of electromagnetic enhancement mechanism of the metal nanomaterials. We have also studied the cytotoxicity of these nanostructures using MTT assay where human lung carcinoma cell line A549 were treated with AuNf. The synthesized gold nanoflowers show high biocompatibility and improved signals when imaged through confocal microscope indicating its applicability as a multimodal in vitro SERS based sensor and imaging tag.