Single plasmonic nanoparticles for ultrasensitive DNA sensing: From invisible to visible

Longhua Guo, Lichan Chen, Seungpyo Hong, Dong Hwan Kim

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The background signal is a major factor that restricts the limit of detection of biosensors. Herein, we present a zero-background DNA-sensing approach that utilizes enzyme-guided gold nanoparticle (AuNP) enlargement. This sensing strategy is based on the finding that small nanoparticles are invisible under a darkfield optical microscope, thus completely eliminating the background signal. In the event of target binding, Ag deposition is triggered and enlarges the AuNP beyond its optical diffraction limit, thereby making the invisible AuNP visible. Because the plasmon scattering of Ag is stronger than that of Au, only a thin layer of Ag is required to greatly enhance the scattering intensity of the AuNPs. Our investigation revealed that a target DNA concentration as low as 5.0×10-21M can transform the darkfield image of the nanoparticle from completely dark (invisible) to a blue dot (visible).

Original languageEnglish
Pages (from-to)266-272
Number of pages7
JournalBiosensors and Bioelectronics
Volume79
DOIs
Publication statusPublished - 2016 May 15

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All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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