A multifunctional β-cyclodextrin-conjugate photodelivering nitric oxide with fluorescence reporting

This contribution reports the design, synthesis and photochemical properties of a novel cationic, water soluble, β-cyclodextrin (βCD) conjugate integrating an anthracene moiety and a nitroaniline derivative within the primary side of the βCD scaffold. Photoinduced energy transfer between the anthracene and the nitroaniline chromophores effectively suppresses the fluorescence of the anthracene unit. Excitation with visible light triggers the release of nitric oxide (NO) from the nitroaniline chromophore, accompanied to the concomitant revival of the anthracene fluorescence, which acts as an optical reporter for detecting the amount of the NO released. Furthermore, the anthracene moiety photogenerates singlet oxygen (1O2) sequentially to NO release. The conjugate is also able to accommodate hydrophobic guests within the βCD cavity, as proven by using naphthalene as a model compound. In view of the key role NO and1O2play as anticancer and antibacterial species, the present βCD derivative represents an intriguing candidate for further studies in biopharmaceutical research addressed to multimodal therapeutic applications.