title: Electrochemical Interrogation of Kinetically-Controlled Dendritic DNA/PNA Assembly for Immobilization-Free and Enzyme-Free Nucleic Acids Sensing.
abstract: We present an immobilization-free and enzyme-free electrochemical nucleic acid sensing strategy, which uses kinetically controlled dendritic assembly of DNA and peptide nucleic acid (PNA). In the presence of a target sequence, ferrocene-labeled PNA probes (Fc-PNAs) and specially designed DNA strands are autonomously assembled into dendritic nanostructures through a cascade of toehold-mediated strand displacement reactions. The consumption of freely diffusible Fc-PNAs (neutrally charged), due to incorporation to DNA/PNA dendrimer, results in a significant electrochemical signal reduction of Fc on a negatively charged electrode from which the hyperbranched and negatively charged dendrimer of DNA/PNA would be electrostatically repelled. The cascade-like assembly process and large electrostatic affinity difference between Fc-PNAs and DNA/PNA dendrimer toward the sensing electrode offer a detection limit down to 100 fM and an inherently high specificity for detecting single nucleotide polymorphisms. The target-triggered mechanism was examined by PAGE analysis, and morphologies of the assembled dendrimers were verified by AFM imaging.
authors: †Division of Biomedical Engineering and ‡Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors: Feng
authors: F
authors: Xuan
authors: †Division of Biomedical Engineering and ‡Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors: Tsz Wing
authors: TW
authors: Fan
authors: †Division of Biomedical Engineering and ‡Department of Chemical and Biomolecular Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors: I-Ming
authors: IM
authors: Hsing
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics; D050091:Dendrimers / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D005296:Ferrous Compounds / Q000737:chemistry; D007700:Kinetics; D000075163:Metallocenes; D049329:Nanostructures / Q000737:chemistry*; D015345:Oligonucleotide Probes / Q000737:chemistry; D020135:Peptide Nucleic Acids / Q000737:chemistry*; D020641:Polymorphism, Single Nucleotide; D055672:Static Electricity
chemical_list: D050091:Dendrimers; D005296:Ferrous Compounds; D000075163:Metallocenes; D015345:Oligonucleotide Probes; D020135:Peptide Nucleic Acids; D004247:DNA; C004998:ferrocene
keywords: DNA/PNA dendrimer; electrochemical detection; enzyme-free; immobilization-free; kinetically controlled assembly