Volume 58, Issue 9 pp. 2558-2569
Minireview

Advanced Photosensitizer Activation Strategies for Smarter Photodynamic Therapy Beacons

Benjamin M. Luby

Benjamin M. Luby

Princess Margaret Cancer Centre and Techna Institute, University Health Network, 101 College St., Toronto, ON, Canada

Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada

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Connor D. Walsh

Connor D. Walsh

Princess Margaret Cancer Centre and Techna Institute, University Health Network, 101 College St., Toronto, ON, Canada

Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada

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Prof. Dr. Gang Zheng

Corresponding Author

Prof. Dr. Gang Zheng

Princess Margaret Cancer Centre and Techna Institute, University Health Network, 101 College St., Toronto, ON, Canada

Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada

Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

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First published: 11 June 2018
Citations: 374

Graphical Abstract

Extreme specificity: Photodynamic therapy beacons are phototoxic drugs that are only cytotoxic upon tissue accumulation, analyte-driven activation, and external illumination. Moreover, their cytotoxic state simultaneously provides optical feedback to monitor treatment. In this Minireview, recent developments on how these beacons are becoming smarter still are discussed.

Abstract

Photodynamic therapy (PDT) is a clinical treatment in which a light-absorbing drug called a photosensitizer (PS) is combined with light and molecular oxygen to generate cytotoxic singlet oxygen. PDT provides additional tissue selectivity compared to conventional chemotherapy as singlet oxygen is generated only in areas in which PS accumulates and that are simultaneously illuminated by a light source with sufficient irradiance and dose. Early PDT beacons built on this concept by adding an analyte-responsive element that simultaneously turns on PDT and fluorescence, providing both an additional layer of selectivity and real-time feedback of the PS′s activation state. More recent PDT beacons have expanded this idea, with new methods now available for sensing analytes, generating singlet oxygen, and reporting treatment status. In this Minireview, we consider developments in advanced activation strategies implemented in therapeutic and theranostic beacons.

Conflict of interest

The authors declare no conflict of interest.

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