title: Morpholino-functionalized silicon nanowire biosensor for sequence-specific label-free detection of DNA.
abstract: We investigated Morpholino-functionalized silicon nanowires (SiNWs) as a novel gene chip platform for the sequence-specific label-free detection of DNA. Morpholino attachment and subsequent Morpholino-DNA hybridization on silicon surface was characterized by X-ray photoelectron spectroscopy and fluorescence microscopy. The resultant Morpholino-modified surfaces showed high specificity of recognition for DNA. Subsequently, by using the same protocol, the surface of the SiNW biosensor was functionalized with Morpholino, and this was used for label-free Morpholino-DNA hybridization detection. Real-time measurements of the Morpholino-functionalized SiNW biosensor exhibited a decrease in a time-dependent conductance when complementary and mutant DNA samples were added. Furthermore, identification of fully complementary versus mismatched DNA samples was carried out by the Morpholino-functionalized SiNW biosensor. We demonstrated that DNA detection using the Morpholino-functionalized SiNW biosensor could be carried out to the hundreds of femtomolar range. The Morpholino-functionalized SiNWs show a novel biosensor for label-free and direct detection of DNA with good selectivity, and a promising application in gene expression.
authors.affiliation: Institute of Microelectronics, Agency for Science, Technology and Research, 11 Science Park Road, Singapore. zhanggj@ime.a-star.edu.sg
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Zhang
authors.forename: Zhan Hong Henry
authors.initials: ZH
authors.lastname: Luo
authors.forename: Min Joon
authors.initials: MJ
authors.lastname: Huang
authors.forename: Guang Kai Ignatius
authors.initials: GK
authors.lastname: Tay
authors.forename: Eu-Jin Andy
authors.initials: EJ
authors.lastname: Lim
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation*; D004247:DNA / Q000032:analysis* / Q000235:genetics*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017403:In Situ Hybridization / Q000295:instrumentation*; D008969:Molecular Sequence Data; D036103:Nanotechnology / Q000295:instrumentation*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000295:instrumentation*; D013194:Staining and Labeling
chemical_list: D004247:DNA