Chiral Guanosine 5ʹ-Monophosphate-Capped Gold Nanoflowers: Controllable Synthesis, Characterization, Surface-Enhanced Raman Scattering Activity, Cellular Imaging and Photothermal Therapy

Plasmonics and chirality in metal nanomaterials are intriguing and inspiring phenomena. Nanoscale chirality of metal nanomaterials has emerged as a hot topic in the past several years. Generally, most plasmon-induced circular dichroism (CD) responses of nanomaterials (> 10 nm) have been artificially created by modifying pre-made achiral nanomaterials with chiral agents, because the in situ generation of plasmon-induced CD responses of nanomaterials with larger size (> 10 nm) is not easy. Herein, we report a simple one-pot green synthesis of chiral gold nanoflowers (GNFs) with abundant petal-shaped tips in the chiral reduction environment arising from the presence of chiral guanosine 5ʹ-monophosphate (5ʹ-GMP) and the chiral reducing agent L-ascorbic acid (L-AA). Different reducing agents can impact the shape and chirality of the products. In addition, the size and chirality of the GNFs can be controlled by adjusting the reaction time. The as-synthesized GNFs have good biocompatibility and can be used for surface-enhanced Raman scattering (SERS) enhancement, cellular dark-field imaging and photothermal therapy.