title: Porphyrinic metal-organic framework as electrochemical probe for DNA sensing via triple-helix molecular switch.
abstract: An electrochemical DNA sensor was developed based on the electrocatalysis of porphyrinic metal-organic framework (MOF) and triple-helix molecular switch for signal transduction. The streptavidin functionalized zirconium-porphyrin MOF (PCN-222@SA) was prepared as signal nanoprobe via covalent method and demonstrated high electrocatalysis for O2 reduction. Due to the large steric effect, the designed nanoprobe was blocked for the interaction with the biotin labeled triple-helix immobilized on the surface of glassy carbon electrode. In the presence of target DNA, the assistant DNA in triple-helix will hybridize with target DNA, resulting in the disassembly of triple-helix molecular. Consequently, the end biotin away from the electrode was ''activated'' for easy access to the signal nanoprobe, PCN-222@SA, on the basis of biotin-streptavidin biorecognition. The introduction of signal nanoprobe to a sensor surface led to a significantly amplified electrocatalytic current towards oxygen reduction. Integrating with DNA recycling ampliﬁcation of Exonuclease III, the sensitivity of the biosensor was improved signiﬁcantly with detection limit of 0.29 fM. Moreover, the present method has been successfully applied to detect DNA in complex serum matrix. This porphyrinic MOF-based strategy has promising application in the determination of various analytes for signal transduction and has great potential in bioassays.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Pinghua
authors.initials: P
authors.lastname: Ling
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China. Electronic address: jpl@nju.edu.cn.
authors.forename: Jianping
authors.initials: J
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D002384:Catalysis; D003217:Conductometry / Q000295:instrumentation*; D004247:DNA / Q000032:analysis* / Q000235:genetics*; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005090:Exodeoxyribonucleases / Q000737:chemistry* / Q000235:genetics; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009930:Organic Chemicals / Q000737:chemistry; D010100:Oxygen / Q000032:analysis / Q000737:chemistry; D011166:Porphyrins / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000295:instrumentation
chemical_list: D015342:DNA Probes; D009930:Organic Chemicals; D011166:Porphyrins; D004247:DNA; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; D010100:Oxygen
keywords: Electrochemical sensor; Metal-organic framework; Porphyrin; Signal amplification; Triple-helix DNA