Défense de thèse de doctorat en sciences chimiques - Rosaria Vulcano

Since azobenzene photoisomerization properties have been discovered in 1937, this molecular switch has been used to modify biomolecules and tune biological functions applying light as an external stimulus.

In the first part of this work, we investigated the mutual influence of the diazo moiety isomerization on H-bonding interactions. For this purpose, two azobenzene derivatives have been designed, where one of the phenyl rings is replaced by the uracil core, the difference consists in the position of the diazo moiety in the nucleobase ring. After exploring different synthetic strategies, both compounds were obtained and their photoisomerization behavior studied, together with the complexation ability in the presence of a complementary diaminopyridine derivative.

In parallel, inspired by the possibility of controlling cell adhesion on a Au surface via an external stimulus, and by the possibility of promoting monodirectional cellular migration following an IGDQ peptide gradient, we designed a new system with the objective of promoting a reversible, bidirectional cellular migration promoted by light. The photoisomerization of the azobenzene amino acids inserted in the peptide sequences would trigger the interaction between the IGDQ terminal exposed on the surface and the integrin receptors on cell membranes, hence redirecting the cells movement upon irradiation. The synthesis of the key light-sensitive amino acids is described as well as their UV-Vis characterization and some preliminary photoisomerization studies.