title: Hierarchy of DNA immobilization and hybridization on poly-L-lysine using an atomic force microscopy study.
abstract: The atomic force microscopy has been used to analyze the immobilization of single stranded DNA on poly-L-lysine-coated glass and subsequent hybridization with complimentary DNA with the Z-threshold parameter and fractal analysis methods. The poly-L-lysine layer, which has a thickness of approximately 7 nm, presents nano-defects that could be critical for DNA immobilization by acting as a nucleation sites for ssDNA and subsequently for dsDNA aggregates. The Z-threshold for the dsDNA aggregates is much larger than for ssDNA, but the statistical fractal dimension is very similar, suggesting a conformal increase of the dimensions of the dsDNA aggregates mainly in the Z-direction, due to an effective ssDNA-ccDNA molecular recognition. This study demonstrates the use of fractal analysis in conjunction with the distribution of heights to evaluate the efficiency of DNA-DNA molecular recognition on surfaces and the impact of nanodefects.
authors.affiliation: Swinburne University of Technology, P.O. Box 218, Hawthorn, Vic 3122, Australia.
authors.forename: P D
authors.initials: PD
authors.lastname: Sawant
authors.forename: G S
authors.initials: GS
authors.lastname: Watson
authors.forename: D
authors.initials: D
authors.lastname: Nicolau
authors.forename: S
authors.initials: S
authors.lastname: Myhra
authors.forename: D V
authors.initials: DV
authors.lastname: Nicolau
mesh_terms: D000327:Adsorption; D001665:Binding Sites; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004247:DNA / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D017403:In Situ Hybridization / Q000379:methods*; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D009690:Nucleic Acid Conformation; D011107:Polylysine / Q000032:analysis / Q000737:chemistry*; D011485:Protein Binding
chemical_list: D020099:Coated Materials, Biocompatible; D011107:Polylysine; D004247:DNA