AuAg-alloy-nanoprobes for specific nucleic acid detection,
Doria, G., Dias {J. T. }, Larguinho M., Pereira E., Franco R., and Baptista P.
, Nanotechnology 2010: Bio Sensors, Instruments, Medical, Environment and Energy - Technical Proceedings of the 2010 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2010, jan, Volume 3, p.62–65, (2010)
AbstractThe derivatization of gold-silver alloy nanoparticles with thiol-ssDNA oligonucleotides (AuAg-alloy-nanoprobes) and their use in nucleic acid detection is presented. A non-cross-linking method has been previously developed by our group using gold nanoparticles, which is based on the colorimetric comparison of solutions before and after salt-induced nanoprobe aggregation. Only the presence of a complementary target stabilizes the nanoprobe, preventing aggregation and colorimetric change after salt addition. Through this approach, the AuAg-alloy-nanoprobes allowed to specifically detect a sequence derived from the RNA polymerase β-subunit gene of Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, with a 2.5-fold enhanced sensitivity (0.3 μg of total DNA) when compared to their gold counterparts.