title: Self-assembled G-quadruplex nanostructures: AFM and voltammetric characterization.
abstract: G-rich oligodeoxynucleotides (ODNs) have great medical and nanotechnological potential, because they can self-assemble into G-quadruplexes and higher-order nanostructures. The folding properties of d(G)10, d(TG9) and d(TG8T) ODNs were studied using atomic force microscopy (AFM) and voltammetry at carbon electrodes. Single-stranded ODNs, in Na(+) containing solutions and for short incubation times, were detected using AFM as network films and polymeric structures and using voltammetry by the occurrence of only the guanine oxidation peak. G-quadruplexes, in Na(+) containing solutions and long incubation times, or in K(+) containing solutions, were detected using AFM as spherical aggregates and using voltammetry by the decrease of the guanine oxidation peak and the occurrence of the G-quartet oxidation peak. Concerning the self-assembling into higher-order nanostructures, d(G)10 was the only sequence forming G-nanowires observed using AFM, d(TG9) formed short G-based super-structures that adsorbed as rod-like shape aggregates, and d(TG8T) formed no nanostructures, due to the presence of thymine residues at both 5' and 3' ends.
authors: Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Coimbra, Portugal.
authors: Ana-Maria
authors: AM
authors: Chiorcea-Paquim
authors: Paulina Viegas
authors: PV
authors: Santos
authors: Ramon
authors: R
authors: Eritja
authors: Ana Maria
authors: AM
authors: Oliveira-Brett
mesh_terms: D055664:Electrochemical Techniques; D054856:G-Quadruplexes; D006147:Guanine / Q000737:chemistry; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry
chemical_list: D009838:Oligodeoxyribonucleotides; D006147:Guanine; D013941:Thymine