Oleic Acid-Assisted Synthesis of Tunable High-Aspect-Ratio Multiply-Twinned Gold Nanorods for Bioimaging

We report a scalable and straightforward seed-mediated strategy to produce high-aspect-ratio (>10) multiply twinned gold nanorods in high yield (>75%–90%) using oleic acid. The results show that the addition of oleic acid to growth solution provides stability to the micellar structure of cetyltrimethylammonium bromide (CTAB), thus leading to the fabrication of high-aspect-ratio gold nanorods. The aspect ratio of nanorods can be tuned by varying the amount of ascorbic acid and the pH of the solution in the presence of oleic acid. Such high-aspect-ratio nanorods could serve as a probe for near-infrared bioimaging applications.