title: 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.
abstract: 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.
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.
authors.forename: Yao
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. rlai2@unl.edu.
authors.forename: Rebecca Y
authors.initials: RY
authors.lastname: Lai
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003596:Cytosine / Q000737:chemistry; D015342:DNA Probes / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D012834:Silver / Q000032:analysis*; D012837:Silver Sulfadiazine / Q000032:analysis
chemical_list: D015342:DNA Probes; D012834:Silver; D003596:Cytosine; D012837:Silver Sulfadiazine
keywords: Adenine; Cytosine; Electrochemical ion sensor; Methylene blue; Silver(I)