title: Ultrasensitive electrical detection of nucleic acids by hematin catalysed silver nanoparticle formation in sub-microgapped biosensors.
abstract: An ultrasensitive electrical detection method of nucleic acids has been demonstrated on sub-microgapped biosensor. In this method, peptide nucleic acid (PNA) probes were firstly immobilized in the gap areas of a pair of interdigited microelectrodes and then were hybridized with their complementary target DNA. After hybridization, hematin molecules were introduced into the DNA strand via zirconium-phosphate and zirconium-carbonate chemistries. The newly attached hematin molecules act as a catalyst to accelerate reducing ammoniacal silver ion to form silver nanoparticles, which span the gap of the interdigitated microelectrode. The conductance of the silver nanoparticles directly correlated with the number of the hybridized DNA molecules. Nearly 1fM sensitivity was achieved under optimal conditions. This approach is also applicable to the detection of RNA.
authors.affiliation: Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore.
authors.forename: J M
authors.initials: JM
authors.lastname: Kong
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: X T
authors.initials: XT
authors.lastname: Chen
authors.forename: N
authors.initials: N
authors.lastname: Balasubramanian
authors.forename: D L
authors.initials: DL
authors.lastname: Kwong
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002384:Catalysis; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006427:Hemin / Q000737:chemistry*; D008839:Microelectrodes; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009696:Nucleic Acids / Q000032:analysis* / Q000737:chemistry*; D010316:Particle Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D009696:Nucleic Acids; D006427:Hemin