Transcription of G-quartet supramolecular aggregates into hierarchical mesoporous silica nanotubes

Abstract

The use of 5-guanosine monophosphate (GMP) with Sr²⁺ ions to form G-quadruplex bundles as supramolecular templates for the preparation of hierarchical mesoporous silica nanotube materials is reported here, and some mesopores with a diameter of 4–22 nm were obtained. Furthermore, some mesopore channels which run perpendicularly to the center axis of the tube and penetrate right through the outer wall of the nanotubes were achieved by removing the templates. Besides, porous hollow silica spheres were obtained by changing some of the reaction conditions during the process of preparation. Their structures are stable even after high temperature calcination. A formation mechanism was proposed and discussed, and their structures were characterized using a number of means including X-ray diffraction, IR spectra, N₂ adsorption–desorption isotherms, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).