Dopamine-assisted one-pot synthesis of gold nanoworms and their application as photothermal agents.

Gold-based nanomaterials of various sizes and geometries have been prepared for use as photothermal agents due to their unique physical and chemical properties. Here we report a simple one-step synthesis of gold nanoworms (NWs) and characterized them with transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Visible spectroscopy, and Fourier transform infrared spectroscopy. The results showed that small gold nanounits were first formed by reducing chloroaurate ions (AuCl4-) with sodium borohydride (NaBH4), and then fused together to form NWs assisted by dopamine (DA), which served a structure-director due to an oriented attachment mechanism. Then DA in the solution was further polymerized into polydopamine (PDA) to form a coating layer on the surface of gold NWs. Moreover, further experiments showed that gold NWs had low cytotoxicity and excellent performance as a photothermal bactericidal on both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. These results show that the synthesized gold NWs are a promising photothermal agent.