One-Pot Photochemical Synthesis of Gold Nanoplates Using Nonionic Diblock Copolymers and their Surface Functionalization

Two-dimensional gold nanoplates (AuNPLs) have been of significant interest because they are ideal substrates for surface modification and surface-enhanced Raman spectroscopy. Conventionally, AuNPLs are synthesized using a seed-mediated growth method employing cetyltrimethylammonium bromide (CTAB) as a shape-directing agent (SDA). The CTAB-based method, however, suffers from cumbersome multistep growth, unsuccessful surface modification, and high cytotoxicity. Therefore, the development of facile and CTAB-free synthesis of AuNPLs is required to address these challenges. Herein, we present a one-pot photochemical synthesis of AuNPLs with an average diameter of 1.5 mu m using a nonionic diblock copolymer, Brij-58, as both an SDA and a reductant. The growth of AuNPLs is thermodynamically and kinetically investigated by controlling the reactant concentrations, reaction temperatures, and head-to-tail ratios of Brij polymers. Furthermore, the synthesis is conducted in the presence of seed particles, resulting in a larger diversity of structures. Notably, the obtained AuNPLs are successively conjugated with thiolated DNA, thus demonstrating the surface potential of the AuNPLs as a reversible assembly platform for bioanalytical applications.