Opportunely designed synthetic DNA oligonucleotides can spontaneously self-assemble into nanosized structures, and can then assume different conformations in response to a variety of external stimuli. Since objects that can modify their shape in response to a stimulus are in principle capable of functional utility, it has been proposed that DNA molecular constructs can be employed as devices. We describe the design, synthesis and characterization of a DNA structure2 capable of repeatedly and rapidly varying its conformation due to the pH-dependent formation and breakdown of a CT-motif DNA triple helix.3 The repeated cycling of the pH between opportune values causes the adduct to intermittently assume a folded or open state, as experimentally confirmed by means of UV, CD and fluorescence spectroscopy, as well as an electrophoretic mobility shift assay. By means of silane chemistry, the nanomotor was then covalently anchored on glass surfaces, and included in various polymer matrices, allowing for single-molecule fluorescence characterizations of its static and dynamic behaviour. This also confirmed that the smooth cycling of the structure is possible in conditions that could hamper the performance of other DNA nanomotors, i.e. in sterically hindered contexts such as at surfaces, and suggesting that it might also work in other systems where diffusion is dominant and the mobility of the species involved in the cycling is critical, e.g. in nano-sized pores. We also suggest potential applications of the structure as a nanodevice, and report preliminary experiments regarding their implementation.

A DNA molecular motor based on a pH-dependent conformational transition.

BRUCALE, MARCO;ZUCCHERI, GIAMPAOLO;SAMORI', BRUNO
2005

Abstract

Opportunely designed synthetic DNA oligonucleotides can spontaneously self-assemble into nanosized structures, and can then assume different conformations in response to a variety of external stimuli. Since objects that can modify their shape in response to a stimulus are in principle capable of functional utility, it has been proposed that DNA molecular constructs can be employed as devices. We describe the design, synthesis and characterization of a DNA structure2 capable of repeatedly and rapidly varying its conformation due to the pH-dependent formation and breakdown of a CT-motif DNA triple helix.3 The repeated cycling of the pH between opportune values causes the adduct to intermittently assume a folded or open state, as experimentally confirmed by means of UV, CD and fluorescence spectroscopy, as well as an electrophoretic mobility shift assay. By means of silane chemistry, the nanomotor was then covalently anchored on glass surfaces, and included in various polymer matrices, allowing for single-molecule fluorescence characterizations of its static and dynamic behaviour. This also confirmed that the smooth cycling of the structure is possible in conditions that could hamper the performance of other DNA nanomotors, i.e. in sterically hindered contexts such as at surfaces, and suggesting that it might also work in other systems where diffusion is dominant and the mobility of the species involved in the cycling is critical, e.g. in nano-sized pores. We also suggest potential applications of the structure as a nanodevice, and report preliminary experiments regarding their implementation.
DNA-based Nanowires: on the Way from Biomolecules to Nanodevices
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Brucale M.; Zuccheri G.; Samorì B.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/15854
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