title: A novel label-free fluorescent sensor for the detection of potassium ion based on DNAzyme.
abstract: A novel label-free and sensitive fluorescent aptasensor for the detection of potassium ion (K(+)) was developed based on the horseradish peroxidase-mimicking DNAzyme (HRP-DNAzyme). In this work, we selected a K(+)-stabilized single stranded DNA (ssDNA) with G-rich sequence as the recognition element. In the presence of K(+), the G-rich DNA folded into the G-quadruplex structure, and then hemin can bind to the G-quadruplex structure as a co-factor and form HRP-DNAzyme. 3-(p-Hydroxyphenyl)-propanoic acid (HPPA) can be oxidized by H(2)O(2) into a fluorescent product in the presence of DNAzyme. The fluorescence intensity of the HPPA oxidative product increased with the K(+) concentration. Under the optimal conditions, the fluorescence intensity was linearly related to the logarithm of K(+) concentration in the range of 2.5 μM to 5mM. Other metal ions, such as Na(+), Li(+), NH(4)(+), Mg(2+) and Ca(2+) caused no notable interference on the detection of K(+).
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Fan
authors.forename: Haitao
authors.initials: H
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.forename: Fanbo
authors.initials: F
authors.lastname: Lin
authors.forename: Lingli
authors.initials: L
authors.lastname: Zhang
authors.forename: Youyu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D015374:Biosensing Techniques; D021881:DNA, Catalytic / Q000737:chemistry* / Q000378:metabolism; D005453:Fluorescence; D054856:G-Quadruplexes; D006427:Hemin / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009841:Oligonucleotides / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D011188:Potassium / Q000097:blood*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D021881:DNA, Catalytic; D009841:Oligonucleotides; D006427:Hemin; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D011188:Potassium