title: Polysaccharide templated silver nanowire for ultrasensitive electrical detection of nucleic acids.
abstract: An ultrasensitive electrical detection method of nucleic acids has been developed on a nanogapped biosensor. In this study, peptide nucleic acid (PNA) probes were immobilized in the gaps of a pair of finger microelectrodes first and were then hybridized with their complementary target DNA. After that, pectin molecules were introduced into the DNA strand via zirconium-phosphate and zirconium-carbonate chemistries and were oxidated by periodate in acetate buffer (pH 3.98). The newly produced aldedyde groups act as a reactant to reduce ammoniacal silver ion to produce silver nanoparticles, which bridged the gap of the interdigitated microelectrode. The conductance of the metallic nanoparticles correlated directly with the amount of the hybridized DNA. A much higher sensitivity was achieved at 3 femtomolar (S/N > 3) under optimal conditions. This biosensor is also applicable to the direct detection of RNA.
authors: Institute of Microelectronics, Agency for Science, Technology and Research, 11 Science Park Road, Science Park II, Singapore, 117685. kongjm@ime.a-star.edu.sg.
authors: Jinming
authors: J
authors: Kong
authors: A R
authors: AR
authors: Ferhan
authors: Xiantong
authors: X
authors: Chen
authors: Li
authors: L
authors: Zhang
authors: Narayanan
authors: N
authors: Balasubramanian
mesh_terms: D015374:Biosensing Techniques; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics; D004563:Electrochemistry / Q000379:methods*; D008958:Models, Molecular; D053770:Nanowires / Q000737:chemistry*; D015345:Oligonucleotide Probes / Q000737:chemistry / Q000235:genetics; D010368:Pectins / Q000737:chemistry; D020135:Peptide Nucleic Acids / Q000737:chemistry; D010504:Periodic Acid / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D012313:RNA / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry
chemical_list: D015345:Oligonucleotide Probes; D020135:Peptide Nucleic Acids; D011134:Polysaccharides; D010504:Periodic Acid; D012834:Silver; D012313:RNA; D010368:Pectins; D004247:DNA; C009288:metaperiodate; D015040:Zirconium