One-step, room temperature, colorimetric detection of mercury (Hg 2+) using DNA/nanoparticle conjugates

Introduction of Hg²⁺ 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 Hg²⁺-mediated formation of T-Hg²⁺-T base pairs as evidenced by an increase in a sharp melting temperature. Copyright © 2008 American Chemical Society.