Distance-mediated plasmonic dimers for reusable colorimetric switches: A measurable peak shift of more than 60 nm

Longhua Guo, Abdul Rahim Ferhan, Hailan Chen, Changming Li, Guonan Chen, Seungpyo Hong, Dong Hwan Kim

Research output: Contribution to journalArticle

51 Citations (Scopus)


The first reconfigurable colorimetric DNA switches based on target DNA binding are reported. This DNA binding actuates a change in the interparticle distance between gold nanoparticle dimers. A significant spectral shift of 68 nm is achievable from on-off switching. The reconfigurability is possible owing to thiol and EDC-imidazole coupling which anchors the DNA linkers to the nanoparticles. The huge spectral shift allows the unaided eye to observe single target biomolecular binding event in real time under a darkfield microscope. The limit-of-detection for target molecules in PBS and human serum are 10 -13 M and 10-11 M respectively. An improved fabrication strategy via asymmetric functionalization is also described, assisted by solid phase synthesis which minimizes the formation of trimers and multimers.

Original languageEnglish
Pages (from-to)234-240
Number of pages7
Issue number2
Publication statusPublished - 2013 Jan 28


All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)

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