title: Crystal violet-G-quadruplex complexes as fluorescent sensors for homogeneous detection of potassium ion.
abstract: A novel K(+) detection method was reported using a label-free G-quadruplex-forming oligonucleotide and a triphenylmethane fluorescent dye crystal violet (CV). This method is based on the fluorescence difference of some CV/G-quadruplex complexes in the presence of K(+) or Na(+), and the fluorescence change with the variation of K(+) concentration. According to the nature of the fluorescence change of CV as a function of ionic conditions, two K(+) detection modes can be developed. One is a fluorescence-decreasing mode, in which T(3)TT(3) (5'-GGGTTTGGGTGGGTTTGGG) is used, and the fluorescence of CV decreases with an increased concentration of K(+). The other is a fluorescence-increasing mode, in which Hum21 (5'-GGGTTAGGGTTAGGGTTAGGG) is used, and the fluorescence of CV increases with an increased concentration of K(+). Compared with some published K(+) detection methods, this method has some important characteristics, such as lower cost of the test, higher concentrations of Na(+) that can be tolerated, adjustable linear detection range and longer excitation and emission wavelengths. Preliminary results demonstrated that the method might be used in biological systems, for example in urine.
authors: Key Laboratory of Functional Polymer Materials (Nankai University), Ministry of Education, Nankai University, Tianjin 300071, PR China. kongdem@nankai.edu.cn
authors: De-Ming
authors: DM
authors: Kong
authors: Jun-Hong
authors: JH
authors: Guo
authors: Wei
authors: W
authors: Yang
authors: Yong-E
authors: YE
authors: Ma
authors: Han-Xi
authors: HX
authors: Shen
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000191:economics / Q000379:methods*; D002942:Circular Dichroism; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D054856:G-Quadruplexes; D005840:Gentian Violet / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry*; D011188:Potassium / Q000032:analysis*; D012680:Sensitivity and Specificity
chemical_list: D005456:Fluorescent Dyes; D009841:Oligonucleotides; D005840:Gentian Violet; D011188:Potassium