title: Influence of tunable external stimuli on the self-assembly of guanosine supramolecular nanostructures studied by atomic force microscope.
abstract: The self-assembly of guanosine (G) molecules on solid surfaces is investigated by tapping-mode atomic force microscopy (AFM) upon controlling and introducing external factors (stimuli) to the G stock solution such as incubation time, presence/absence of metal cations, and mechanical shaking. Surprisingly, at different stages of incubation time at room temperature and in the absence of any metal cations in the G stock solution, which are known to be one of the governing factors in forming G-nanostructures, two assembly pathways resulting into two distinct supramolecular nanostructures were revealed. Astonishingly, by introducing a mechanical shaking of the tube containing the G stock solution, one-dimensional (1D) wires of G molecules are observed by AFM, and very interestingly, novel "branched" supramolecular nanostructures are formed. We have also observed that the later branched G nanostructures can grow further into a two-dimensional (2D) thin film by increasing the incubation time of the G stock solution at room temperature after it is exposed to the external mechanical stimuli. The self-assembled nanostructures of G molecules are changed significantly by tuning the assembly conditions, which show that it is indeed possible to grow complex 2D nanostructures from simple nucleoside molecules.
authors.affiliation: Institute of Photo-Biophysics, Physics and Electronics Department, Henan University, 475004, Kaifeng, China.
authors.forename: Yinli
authors.initials: Y
authors.lastname: Li
authors.forename: Mingdong
authors.initials: M
authors.lastname: Dong
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Otzen
authors.forename: Yuheng
authors.initials: Y
authors.lastname: Yao
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.forename: Flemming
authors.initials: F
authors.lastname: Besenbacher
authors.forename: Wael
authors.initials: W
authors.lastname: Mamdouh
mesh_terms: D006151:Guanosine / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000379:methods*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology
chemical_list: D006151:Guanosine