A reagentless DNA-based electrochemical silver(I) sensor for real time detection of Ag(I) – the effect of probe sequence and orientation on sensor response

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Ag(I) is known to interact with cytosine (C) via the formation C-Ag(I)-C complexes. The authors have utilized this concept to design six electrochemical Ag(I) sensors using C-rich DNA probes. Alternating current voltammetry and cyclic voltammetry were used to analyze the sensors. The results show that the dual-probe sensors that require the use of both 5'- and 3'-thiolated DNA probes are not suitable for this application, the differences in probe orientation impedes formation of C-Ag(I)-C complexes. Sensors fabricated with DNA probes containing both thymine (T) and C, independent of the location of the alkanethiol linker, do not response to Ag(I) either; T-T mismatches destabilize the duplex even in the presence of Ag(I). However, sensors fabricated with DNA probes containing both adenine (A) and C are ideal for this application, owing to the formation of C-Ag(I)-C complexes, as well as other lesser known interactions between A and Ag(I). Both sensors are sensitive, specific and selective enough to be used in 50% human saliva. They can also be used to detect silver sulfadiazine, a commonly prescribed antimicrobial drug. With further optimization, this sensing strategy may offer a promising approach for detection of Ag(I) in environmental and clinical samples.

Original languageEnglish (US)
Pages (from-to)788-796
Number of pages9
JournalBiotechnology Journal
Issue number6
StatePublished - Jun 1 2016



  • Adenine
  • Cytosine
  • Electrochemical ion sensor
  • Methylene blue
  • Silver(I)

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Molecular Medicine

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