A Colorimetric Lead Biosensor Using DNAzyme-Directed Assembly of Gold Nanoparticles

A highly sensitive and selective colorimetric lead biosensor based on DNAzyme-directed assembly of gold nanoparticles is reported. It consists of a DNAzyme and its substrate that can hybridize to a 5'-thio-modified DNA attached to gold nanoparticles. The hybridization brings gold nanoparticles together, resulting in a blue-colored nanoparticle assembly. In the presence of lead, the DNAzyme catalyzes specific hydrolytic cleavage, which prevents the formation of the nanoparticle assembly, resulting in red-colored individual nanoparticles. The detection level can be tuned to several orders of magnitude, from 100 nM to over 200 muM, through addition of an inactive variant of the DNAzyme. The concept developed here…

• DO
  Division of Materials Research