Library approach for reliable synthesis and properties of DNA-gold nanorod conjugates.

We developed a library-based approach to chemically stabilize cetyltrimethylammonium bromide (CTAB)-coated gold nanorods for the synthesis of polyvalent DNA-gold nanorod conjugates (DNA-AuNRs). Eleven chemical reagents were carefully chosen to constitute an additive library and screened by UV-vis spectroscopy to evaluate their stabilizing capability for the CTAB-coated AuNRs. Interestingly, 5-bromosalicylic acid (5-BrSA) was determined to most significantly stabilize the AuNRs by inducing additional adsorption of CTAB on the rod. Importantly, these stabilized AuNRs with 5-BrSA were conjugated with thiol DNA in an exceptionally reproducible and reliable method, which led to the systematic investigation of their cooperative assembly and disassembly properties under various conditions, including different types and lengths of the DNA sequences.