Rapid Aggregation of Gold Nanoparticles Induced by Non-Cross-Linking DNA Hybridization

To date, aggregation of DNA-functionalized gold nanoparticles by hybridization of target DNA in a cross-linking configuration has been intensively studied. Here, we report that aggregation in a non-cross-linking configuration is also possible and is even better from the viewpoint of genetic analysis because of its speed and sensitivity. In this system, 15 nm diameter gold nanoparticles functionalized with (alkanethiol)-15mer DNA are hybridized to target 15mer DNA at room temperature. At high NaCl concentration (>/=0.5 M), hybridization with complementary target DNA induces nanoparticle aggregation based on the salting-out effect. The aggregation can be detected by a colorimetric change of the colloidal…