Aptamer-based multicolor fluorescent gold nanoprobes for multiplex detection in homogeneous solution.

The design of a novel multicolor fluorescent gold nanoprobe for homogeneous detection of small-molecule targets is reported, which combines the specific binding abilities of aptamers with the ultrahigh quenching ability of gold nanoparticles (AuNPs). Dye-tagged aptamers and their complementary sequence with thiol labels are co-assembled at the surface of AuNPs. As a proof of concept, it is demonstrated that such a multicolor fluorescent gold nanoprobe can simultaneously detect adenosine, potassium ion, and cocaine with high selectivity. This potentially generic strategy is shown to be promising for rapid screening of small molecular targets.