Accelerated color change of gold nanoparticles assembled by DNAzymes for simple and fast colorimetric Pb2+ detection

Juewen Liu, Yi Lu

Research output: Contribution to journalArticlepeer-review


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 pb2+-dependent DNAzyme. However, heating to 50 °C followed by a cooling process of ∼2 h was required to observe the color change. Herein we report a new improved design that allows fast (< 10 min) detection of Pb2+ at ambient temperature. This improvement of sensor performance is a result of detailed studies of the DNAzyme and nanoparticles, which identified "tail-to-tail" nanoparticle alignment, and large (42 nm diameter) nanoparticle size as the major determining factors in allowing fast color changes. The optimal conditions for other factors such as temperature (35 °C) and concentrations of the DNAzyme (2 μM), its substrate (3 nM), and NaCl (300 mM) have also been determined. These results demonstrate that fundamental understanding of the DNAzyme biochemistry and nanoparticle science can lead to dramatically improved colorimetric sensors.

Original languageEnglish (US)
Pages (from-to)12298-12305
Number of pages8
JournalJournal of the American Chemical Society
Issue number39
StatePublished - Oct 6 2004

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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