Synthesis of less toxic gold nanorods by using dodecylethyldimethylammonium bromide as an alternative...

Gold nanoparticles having a rod-like morphology are regularly investigated as potential nano-therapeutic materials owing to their interesting optical properties, facile surface modification, tunable aspect ratios, and low cytotoxicity. Gold nanorods are historically prepared starting from HAuCl₄ in the presence of ascorbic acid, silver nitrate, and the growth directing surfactant, cetyltrimethylammonium bromide (CTAB). While CTAB drives a rod-like morphology, it is known to be cytotoxic. This inherent toxicity is often addressed by removing or masking the native CTAB surfactant present on the nanorod surface. In the current study we have investigated a less toxic alternative surfactant, dodecylethyldimethylammonium bromide (C₁₂EDMAB), as a possible growth-directing agent. Monodisperse gold nanorods having various lengths have been grown in the presence of C₁₂EDMAB. SEM data suggests that the quantity of C₁₂EDMAB on the rod's surface is much higher than that of CTAB. Toxicity assays were performed on HEp-2 and A549 cells showing lower toxicity at select concentrations for C₁₂EDMAB coated rods.