Massimo Bergamin

Two-Dimensional Diffusion-Ordered NMR Spectroscopy as a Tool for Monitoring Functionalized Carbon Nanotube Purification and Composition

Functionalized carbon nanotube (CNT) derivatives are currently under thorough investigation in different biomedical investigations. In this field of research, the composition of sample either in terms of covalently attached or physisorbed moieties can greatly affect the observed results and hamper the comparison between different studies. Therefore, the availability of a fast and reliable analytical technique to assess both the type of interaction (covalent vs noncovalent) and the composition of CNT conjugates is of great importance. Here we describe that the two-dimensional diffusion-ordered (DOSY) NMR spectroscopy is extremely useful to discriminate between conjugated and unconjugated polyethylene glycol groups in samples obtained by condensation with oxidized single-walled carbon nanotubes (SWNTs). This fast and nondestructive technique allows us to follow the removal of unconjugated polyethylene glycol chains during the purification. In particular, DOSY analysis reveal that about 1/3 (wt %) of the polyethylene glycol used for the condensation remained physisorbed to functionalized SWNTs after dialysis. Complete elimination of physisorbed polyethylene glycol was achieved using diafiltration.

Synthesis and Molecular Modeling Studies of Fullerene−5,6,7-Trimethoxyindole−Oligonucleotide Conjugates as Possible Probes for Study of Photochemical Reactions in DNA Triple Helices

The synthesis of novel functionalized fullerene derivatives containing DNA minor groove binders is reported. In order to construct sequence-specific probes for DNA photomodification, the compounds were attached to a triple helix forming oligonucleotide, and the formation of triplexes was monitored. The triplex formation was demonstrated, but the presence of fullerene moieties gives rise to a high degree of instability. Molecular modeling studies on these supramolecular structures provided useful information for the current study and for future developments.

Synthesis of a hybrid fullerene–trimethoxyindole–oligonucleotide conjugate

The synthesis of novel functionalized fullerene derivatives is reported: a DNA minor groove binder such as trimethoxy- indole-2-carboxylate (TMI) and an oligonucleotide chain have been covalently linked to C60 with the aim of duplicating DNA interactions for increasing sequence selectivity.