title: Detection of MicroRNAs using target-guided formation of conducting polymer nanowires in nanogaps.
abstract: A nanogapped microelectrode-based biosensor array is fabricated for ultrasensitive electrical detection of microRNAs (miRNAs). After peptide nucleic acid (PNA) capture probes were immobilized in nanogaps of a pair of interdigitated microelectrodes and hybridization was performed with their complementary target miRNA, the deposition of conducting polymer nanowires, polyaniline (PAn) nanowires, is carried out by an enzymatically catalyzed method, where the electrostatic interaction between anionic phosphate groups in miRNA and cationic aniline molecules is exploited to guide the formation of the PAn nanowires onto the hybridized target miRNA. The conductance of the deposited PAn nanowires correlates directly to the amount of the hybridized miRNA. Under optimized conditions, the target miRNA can be quantified in a range from 10 fM to 20 pM with a detection limit of 5.0 fM. The biosensor array is applied to the direct detection of miRNA in total RNA extracted from cancer cell lines.
authors.affiliation: Institute of Microelectronics, 11 Science Park Road, Singapore 117685, Republic of Singapore.
authors.forename: Yi
authors.initials: Y
authors.lastname: Fan
authors.forename: Xiantong
authors.initials: X
authors.lastname: Chen
authors.forename: Alastair D
authors.initials: AD
authors.lastname: Trigg
authors.forename: Chih-hang
authors.initials: CH
authors.lastname: Tung
authors.forename: Jinming
authors.initials: J
authors.lastname: Kong
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Gao
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D015374:Biosensing Techniques; D004553:Electric Conductivity; D006046:Gold / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000737:chemistry; D007202:Indicators and Reagents; D008670:Metals / Q000737:chemistry; D035683:MicroRNAs / Q000737:chemistry*; D046228:Microarray Analysis; D008839:Microelectrodes; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D053758:Nanoparticles; D009693:Nucleic Acid Hybridization; D011108:Polymers; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000814:Aniline Compounds; D007202:Indicators and Reagents; D008670:Metals; D035683:MicroRNAs; D011108:Polymers; D006046:Gold; D006735:Horseradish Peroxidase