title: A fluorescent aptasensor for potassium ion detection-based triple-helix molecular switch.
abstract: Here, a biosensor based on a quadruplex-forming aptamer for the determination of potassium ion (K(+)) is presented. The aptamer was used as a molecular recognition element; it was adjacent to two arm fragments and a dual-labeled oligonucleotide serving as a signal transduction probe (STP) that is complementary of the arm fragment sequence. In the presence of K(+), the aptamer was displaced from the STP, which was accompanied by decreased signal. The quenching percentage of fluorescence intensity was proportional to the concentration of K(+) in the range of 0.05 to 1.4mM. A detection limit of 0.014 mM was achieved. Furthermore, other metal ions, such as Na(+), Li(+), NH4(+), Mg(2+), and Ca(2+), caused no notable interference on the detection of K(+).
authors.affiliation: Biophysical Chemistry Laboratory, Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran. Electronic address: asma_verdian@yahoo.com.
authors.forename: A
authors.initials: A
authors.lastname: Verdian-Doghaei
authors.affiliation: Biophysical Chemistry Laboratory, Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran.
authors.forename: M R
authors.initials: MR
authors.lastname: Housaindokht
authors.affiliation: Pharmaceutical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Kh
authors.initials: Kh
authors.lastname: Abnous
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001681:Biological Assay / Q000295:instrumentation* / Q000379:methods*; D007477:Ions / Q000032:analysis; D057230:Limit of Detection; D011188:Potassium / Q000032:analysis*; D013050:Spectrometry, Fluorescence
chemical_list: D052157:Aptamers, Nucleotide; D007477:Ions; D011188:Potassium
keywords: Aptamer; Biosensor; Fluorescence aptasensor; G-quadruplex; Potassium ion