title: Release and report: a new photolabile caging system with a two-photon fluorescence reporting function.
abstract: A new efficient photocaging system with a fluorescence reporting function has been developed. The photolabile latch is based on adducts of C-nucleophiles with aromatic ketones, such as thioxanthones and xanthones. The system is designed to quantify the release of biological effectors and to monitor their spatial distribution and localization by single- and two-photon fluorescence microscopy. In the armed state the ketone's conjugation is disrupted by nucleophilic addition, resulting in a blue shift of the absorption maxima and a dramatic decrease in fluorescence intensity. The mechanism of the photoinduced uncaging involves homolytic C-C bond fragmentation followed by radical disproportionation, regenerating the carbonyl moiety and restoring fluorescence. The uncaging can be initiated via either a one- or two-photon process, offering a new powerful tool for molecular life sciences. The synthesis and uncaging of dendrimer- and polymeric bead-based model systems are described.
authors.affiliation: Department of Chemistry and Biochemistry, University of Denver, 2190 East Iliff Avenue, Denver, Colorado 80208-2436, USA.
authors.forename: Janaki R R
authors.initials: JR
authors.lastname: Majjigapu
authors.forename: Alexei N
authors.initials: AN
authors.lastname: Kurchan
authors.forename: Rudresha
authors.initials: R
authors.lastname: Kottani
authors.forename: Tiffany P
authors.initials: TP
authors.lastname: Gustafson
authors.forename: Andrei G
authors.initials: AG
authors.lastname: Kutateladze
mesh_terms: D007659:Ketones / Q000737:chemistry*; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D015394:Molecular Structure; D010777:Photochemistry; D013892:Thioxanthenes / Q000737:chemistry; D044004:Xanthones / Q000737:chemistry
chemical_list: D007659:Ketones; D013892:Thioxanthenes; D044004:Xanthones; C009689:xanthone; C484911:thioxanthone