One-Step, Room Temperature, Colorimetric Detection of Mercury (Hg²⁺) Using DNA/Nanoparticle Conjugates

Introduction of Hg 2+ into an aqueous solution containing oligonucleotide-tethered gold nanoparticle probes and a linker oligonucleotide with a number of thymine−thymine (T−T) mismatches results in the formation of particle aggregates at room temperature with a concomitant colorimetric response. The high selectivity of this detection system is attributed to Hg 2+ -mediated formation of T−Hg 2+ −T base pairs as evidenced by an increase in a sharp melting temperature.