title: Input-dependent induction of G-quadruplex formation for detection of lead (II) by fluorescent ion logic gate.
abstract: A label-free fluorescent AND logic gate has been developed utilizing ion-tuned configuration conversion of DNA probe with K(+) and Pb(2+) as two inputs. A well-designed hairpin DNA which is composed of a poly-G loop and a GR-5 DNAzyme stem serves as a recognition probe, and an derivative of aloe-emodin (AED) was designed and synthesized as signal probe. In the presence of Pb(2+), the substrate strand of DNAzyme is irreversibly and specifically cleaved at the cleavage site, which made the poly-G loop form G-quadruplex in the presence of a constant concentration of K(+). Such a structural change significantly affects the spectral behaviors of AED, which can be explored to ultra-sensitively detect Pb(2+) with a limit of detection of 22.8pM. By combing the high specificity of hairpin DNA and GR-5 DNAzyme, Pb(2+) can be highly selectively detected even when coexisted with other metal ions. Circular dichroism (CD), UV-vis absorption spectrometry and fluorescence polarization (FP) measurements further verified the reliability and reasonability of the sensing mechanism. Therefore, it provides a simple and label-free approach to detect ions with high sensitivity and specificity, and promises to provide a solid sensing platform for the detection of targets by altering the specific sequence of nucleic acid probe.
authors: Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China.
authors: Yina
authors: Y
authors: Zhao
authors: Qi
authors: Q
authors: Zhang
authors: Wenhong
authors: W
authors: Wang
authors: Yan
authors: Y
authors: Jin
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004247:DNA / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D054856:G-Quadruplexes; D007477:Ions; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*
chemical_list: D007477:Ions; D007854:Lead; D004247:DNA