title: Electrochemical detection of oligonucleotide by attaching redox probes onto its backbone.
abstract: An approach was demonstrated to detect oligonucleotide by attaching redox probes onto its backbone. First, peptide nucleic acid (PNA) with a neutral backbone was immobilized onto a gold (Au) electrode surface as a capture. Second, when the PNA capture hybridized with a target oligonucleotide (a short DNA), an assembly of Au-PNA-DNA formed and phosphate groups were thus brought into the assembly from the DNA's backbone. The linker ion of Zr(4+) exhibits a strong coordination interaction with the phosphate group and the carboxylic group. The hybridized target DNA provides the phosphate group while a derivatized redox probe of ferrocene (Fc) carboxyl acid offers the carboxylic group. Therefore, the redox probe can be attached to the phosphate group by the linker to form an assembly of Au-PNA-DNA-Zr-Fc. Its redox process was studied and the detection conditions of oligonucleotide were optimized. A limit of detection of 1.0×10(-12) M or ∼2 attomol was reached.
authors.affiliation: Institute of Microelectronics, Agency for Science, Technology and Research, 11 Science Park Road, Singapore Science Park II, Singapore. fangc@ime.a-star.edu.sg
authors.forename: Cheng
authors.initials: C
authors.lastname: Fang
authors.forename: Hongmiao
authors.initials: H
authors.lastname: Ji
authors.forename: Wang Yanping
authors.initials: WY
authors.lastname: Karen
authors.forename: Siti Rafeah Mohamed
authors.initials: SR
authors.lastname: Rafei
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D015342:DNA Probes / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D009841:Oligonucleotides / Q000032:analysis* / Q000235:genetics*; D010084:Oxidation-Reduction
chemical_list: D015342:DNA Probes; D009841:Oligonucleotides