title: Assessment of water-soluble pi-extended squaraines as one- and two-photon singlet oxygen photosensitizers: design, synthesis, and characterization.
abstract: Singlet oxygen sensitization by organic molecules is a topic of major interest in the development of both efficient photodynamic therapy (PDT) and aerobic oxidations under complete green chemistry conditions. We report on the design, synthesis, biology, and complete spectroscopic characterization (vis-NIR linear and two-photon absorption spectroscopy, singlet oxygen generation efficiencies for both one- and two-photon excitation, electrochemistry, intrinsic dark toxicity, cellular uptake, and subcellular localization) of three classes of innovative singlet oxygen sensitizers pertaining to the family of symmetric squaraine derivatives originating from pi-excessive heterocycles. The main advantage of pi-extended squaraine photosensitizers over the large number of other known photosensitizers is their exceedingly strong two-photon absorption enabling, together with sizable singlet oxygen sensitization capabilities, for their use at the clinical application relevant wavelength of 806 nm. We finally show encouraging results about the dark toxicity and cellular uptake capabilities of water-soluble squaraine photosensitizers, opening the way for clinical small animal PDT trials.
authors.affiliation: Department of Materials Science and INSTM, University of Milano-Bicocca, via Cozzi 53, I-20125 Milano, Italy. luca.beverina@mater.unimib.it
authors.forename: Luca
authors.initials: L
authors.lastname: Beverina
authors.forename: Maurizio
authors.initials: M
authors.lastname: Crippa
authors.forename: Mirko
authors.initials: M
authors.lastname: Landenna
authors.forename: Riccardo
authors.initials: R
authors.lastname: Ruffo
authors.forename: Patrizio
authors.initials: P
authors.lastname: Salice
authors.forename: Fabio
authors.initials: F
authors.lastname: Silvestri
authors.forename: Silvia
authors.initials: S
authors.lastname: Versari
authors.forename: Alessandro
authors.initials: A
authors.lastname: Villa
authors.forename: Luca
authors.initials: L
authors.lastname: Ciaffoni
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Collini
authors.forename: Camilla
authors.initials: C
authors.lastname: Ferrante
authors.forename: Silvia
authors.initials: S
authors.lastname: Bradamante
authors.forename: Claudio M
authors.initials: CM
authors.lastname: Mari
authors.forename: Renato
authors.initials: R
authors.lastname: Bozio
authors.forename: Giorgio A
authors.initials: GA
authors.lastname: Pagani