Coined by researchers A. Paul Alivisatos and Peter G. Schultz, it is a term used to describe double-stranded DNA molecules that have attached to them several multi-atom clusters of gold. As of 1 996, these researchers were working to try to create nanometerscale electrical circuits, semiconductors, etc.
A separate methodology, researched by Chad A. Mirkin et al., utilizes strands of DNA to reversibly assemble gold nanoparticles (nanometer-scale multi-atom particles) into supramolecular (many molecule) agglomerations, in which the gold particles are separated from each other by a distance of approximately 60 Angstroms. The aggregation of these DNA-metal nanoparticles causes a visible color change to occur. As of 1996, these researchers were working to try to create simple and rapid tests that would indicate the presence of a virus (e.g., HIV-1 or HIV-2) via a visible color change. Such a test would use two noncomplementary DNA sequences, each of which has attached to it a gold nanoparticle (via a thiol group). The two sequences would be selected for their ability to latch onto a target sequence in the desired virus, but they would be unable to combine with each other, since they are noncomplementary. When double-stranded DNA molecules possessing two “sticky ends” (that are complementary to the sequences attached to virus) are added, the resultant color change indicates virus presence.