silicon and n-octadecyltrimethoxysilane

Alkyl groups of n-octadecyltrimethoxysilane (ODS) in a self-assembled monolayer on a silicon substrate were oxidized to carboxyl groups by partial irradiation of vacuum ultra-violet light under the photomask, producing a COOH/ODS line pattern. After active esterification of carboxyl groups, two kinds of amine-terminated dendrimers, poly(propyleneimine) and poly(amido amine) (PAMAM) dendrimers, were immobilized on a COOH line through amide-bond so that photolithographic dendrimer/ODS pattern was finally fabricated. Preparation was certified by atomic force microscopy (AFM) and surface-enhanced infrared absorption spectroscopy at transmission mode. Adsorption of linear macromolecules was examined on PAMAM dendrimer/ODS pattern. After adsorption of poly-L-glutamic acid (PGA) at a pH below alpha-helix--random coil transition, rod-shape texture was observed only on the dendrimer line in an AFM image. This texture is an aggregate of alpha-helical PGA. Sodium hyaluronate and DNA were also adsorbed selectively on the dendrimer line, keeping the line profile, although characteristic textures were not observed.

Topics: Adsorption; Amines; Biocompatible Materials; Dendrimers; DNA; Electrochemistry; Hyaluronic Acid; Hydrogen Bonding; Hydrogen-Ion Concentration; Macromolecular Substances; Microscopy, Atomic Force; Nucleic Acid Conformation; Organosilicon Compounds; Polyamines; Polyglutamic Acid; Polymers; Silicon; Spectrophotometry; Surface Properties; Ultraviolet Rays

Nanoscale patterns of modified oligonucleotides are produced on octadecyltrimethoxysilane self-assembled monolayers at a silicon surface by electron beam lithography. DNA structures with feature sizes of the order of 250 nm were detected by epi-fluorescence microscopy.

Topics: DNA; Microscopy, Electron; Microscopy, Fluorescence; Nanostructures; Oligodeoxyribonucleotides; Organosilicon Compounds; Silicon; Surface Properties