Letter abstract


Nature Photonics 2, 420 - 424 (2008)
Published online: 30 May 2008 | doi:10.1038/nphoton.2008.100

Subject Category: Biophotonics

Blood-vessel closure using photosensitizers engineered for two-photon excitation

Hazel A. Collins1, Mamta Khurana2, Eduardo H. Moriyama2,3, Adrian Mariampillai2, Emma Dahlstedt1, Milan Balaz1, Marina K. Kuimova4, Mikhail Drobizhev5, Victor X. D. Yang2,3, David Phillips4, Aleksander Rebane5, Brian C. Wilson2 & Harry L. Anderson1


The spatial control of optical absorption provided by two-photon excitation has led to tremendous advances in microscopy1 and microfabrication2. Medical applications of two-photon excitation in photodynamic therapy3, 4 have been widely suggested5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, but thus far have been rendered impractical by the low two-photon cross-sections of photosensitizer drugs (which are compounds taken up by living tissues that become toxic on absorption of light). The invention of efficient two-photon activated drugs will allow precise three-dimensional manipulation of treatment volumes, providing a level of targeting unattainable with current therapeutic techniques. Here we present a new family of photodynamic therapy drugs designed for efficient two-photon excitation and use one of them to demonstrate selective closure of blood vessels through two-photon excitation photodynamic therapy in vivo. These conjugated porphyrin dimers have two-photon cross-sections that are more than two orders of magnitude greater than those of standard clinical photosensitizers17. This is the first demonstration of in vivo photodynamic therapy using a photosensitizer engineered for efficient two-photon excitation.

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  1. Department of Chemistry, Oxford University, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
  2. Department of Medical Biophysics, Ontario Cancer Institute, University of Toronto, Toronto M5G 2M9, Canada
  3. Department of Physics, Ryerson University, Toronto M5B 2K3, Canada
  4. Chemistry Department, Imperial College London, Exhibition Road, London SW7 2AZ, UK
  5. Department of Physics, Montana State University, Bozeman, Montana 5917-384, USA

Correspondence to: Harry L. Anderson1 e-mail: harry.anderson@chem.ox.ac.uk

Correspondence to: Brian C. Wilson2 e-mail: wilson@uhnres.utoronto.ca



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