title: End-specific strategies of attachment of long double stranded DNA onto gold-coated nanofiber arrays.
abstract: We report the effective and site-specific binding of long double stranded (ds)DNA to high aspect ratio carbon nanofiber arrays. The carbon nanofibers were first coated with a thin gold layer to provide anchorage for two controllable binding methods. One method was based on the direct binding of thiol end-labeled dsDNA. The second and enhanced method used amine end-labeled dsDNA bound with crosslinkers to a carboxyl-terminated self-assembled monolayer. The bound dsDNA was first visualized with a fluorescent, dsDNA-intercalating dye. The specific binding onto the carbon nanofiber was verified by a high resolution detection method using scanning electron microscopy in combination with the binding of neutravidin-coated fluorescent microspheres to the immobilized and biotinylated dsDNA. Functional activity of thiol end-labeled dsDNA on gold-coated nanofiber arrays was verified with a transcriptional assay, whereby Chinese hamster lung cells (V79) were impaled upon the DNA-modified nanofibers and scored for transgene expression of the tethered template. Thiol end-labeled dsDNA demonstrated significantly higher expression levels than nanofibers prepared with control dsDNA that lacked a gold-binding end-label. Employing these site-specific and robust techniques of immobilization of dsDNA onto nanodevices can be of advantage for the study of DNA/protein interactions and for gene delivery applications.
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6030, USA. University of Tennessee in Knoxville, Knoxville, TN 37996-2200, USA.
authors.forename: Diana B
authors.initials: DB
authors.lastname: Peckys
authors.forename: Niels
authors.initials: N
authors.lastname: de Jonge
authors.forename: Michael L
authors.initials: ML
authors.lastname: Simpson
authors.forename: Timothy E
authors.initials: TE
authors.lastname: McKnight