Accelerated Color Change of Gold Nanoparticles Assembled by DNAzymes for Simple and Fast Colorimetric Pb 2+ Detection

The combination of high metal selectivity of DNAzymes with the strong distance-dependent optical properties of metallic nanoparticles has presented considerable opportunities for designing colorimetric sensors for metal ions. We previously communicated a design for a colorimetric lead sensor based on the assembly of gold nanoparticles by a Pb(2+)-dependent DNAzyme. However, heating to 50 degrees C followed by a cooling process of approximately 2 h was required to observe the color change. Herein we report a new improved design that allows fast (