title: DNA immobilization chemical interference due to aggregates study by Dip and Drop approach.
abstract: In the present manuscript, we report the studies and observations for chemical interference due to aggregates formation during covalent immobilization of thiolated lambda-DNA between gold microelectrodes. Dip and Drop approaches were employed to study DNA immobilization using thiolated oligos (oligoA 5' GGGCGGCGACCT 3' and oligoB 5' AGGTCGCCGCCC 3'). As a result of aggregation, less interference was observed in Dip approach as compared to Drop approach. Atomic Force Microscopy (AFM) analysis of piranha treated gold surface revealed 47.5% increase in height roughness, contributing in interference by creating active sites. Cyclic voltammetry (CV) studies ascertain the multitude of adsorption states existing in long strand of DNA on surface. Surface coverage was found to be approximately 72% (1.35x10(10) molecules/cm(2)), and approximately 42% (7.89x10(9) molecules/ cm(2)) in Dip and Drop approach, respectively. Dip approach can be used as a measure to minimize interference due to aggregation.
authors.affiliation: Biomolecular Electronics and Nanotechnology Division (BEND), Central Scientific Instruments Organization (CSIO), Sector-30C, Chandigarh, India. ajore_r@rediffmail.com
authors.forename: Ram
authors.initials: R
authors.lastname: Ajore
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kumar
authors.forename: Inderpreet
authors.initials: I
authors.lastname: Kaur
authors.forename: R C
authors.initials: RC
authors.lastname: Sobti
authors.forename: Lalit M
authors.initials: LM
authors.lastname: Bharadwaj
mesh_terms: D000327:Adsorption; D010582:Bacteriophage lambda / Q000737:chemistry; D001483:Base Sequence; D001672:Biocompatible Materials / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D004279:DNA, Viral / Q000737:chemistry; D004563:Electrochemistry; D006046:Gold; D046911:Macromolecular Substances / Q000737:chemistry; D008839:Microelectrodes; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D013499:Surface Properties; D013873:Thionucleotides / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D004279:DNA, Viral; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D013873:Thionucleotides; D006046:Gold; D004247:DNA