Morphological studies of oligodeoxyribonucleotides probes covalently immobilized at polystyrene modified surfaces.
The immobilization of short ss-DNA (18- and 36-mer) and their hybridization were studied at gold and glassy carbon substrates modified with low molecular weight (approximately 12, 18 and 24 kg/mol) polystyrene thin films. Amino-modified DNA was attached to the surface by reaction with succinimide ester groups bound to the polystyrenes. A ferrocene modified DNA target was used to confirm the probe-target hybridization. Atomic force microscopy studies showed significant morphological changes after probe immobilization and hybridization compared to the featureless structure of the polystyrene film. Single-stranded DNA samples had a globular morphology with an average density of 3.8 and 2.2 (x 10(11)) globules/cm2 for the 18- and 36-mer, respectively. The formation of a porous structure with a 2.0 and 1.0 (x10(11)) average pore density corresponding to the 18- and 36-mer was observed after hybridization. A surface composition analysis was done by X-ray photoelectron spectroscopy to confirm and support the images interpretation. Ferrocene oxidation (+323 mV/18-mer, +367 mV/36-mer, versus Ag/AgCl) proved the presence of ds-DNA at the modified surfaces.
Department of Chemistry, P.O. Box 23346, University of Puerto Rico, Río Piedras Campus, San Juan, PR 00931-3346, USA.
Lisa
L
Muñoz-Serrano
Ana R
AR
Guadalupe
Esther
E
Vega-Bermudez
D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D015342:DNA Probes / Q000737:chemistry* / Q000648:ultrastructure*; D017403:In Situ Hybridization / Q000379:methods*; D008422:Materials Testing; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D010316:Particle Size; D011137:Polystyrenes / Q000737:chemistry*; D013499:Surface Properties
D020099:Coated Materials, Biocompatible; D015342:DNA Probes; D009838:Oligodeoxyribonucleotides; D011137:Polystyrenes