Theranostics 2015; 5(5):469-476. doi:10.7150/thno.10694

Research Paper

Nano-Enabled SERS Reporting Photosensitizers

Arash Farhadi1,2, Áron Roxin1,3, Brian C. Wilson1,2, Gang Zheng1,2,3 ✉

1. Princess Margaret Cancer Centre, UHN, Toronto, Ontario, Canada
2. Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
3. Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) License. See for full terms and conditions.
Farhadi A, Roxin Á, Wilson BC, Zheng G. Nano-Enabled SERS Reporting Photosensitizers. Theranostics 2015; 5(5):469-476. doi:10.7150/thno.10694. Available from

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To impart effective cellular damage via photodynamic therapy (PDT), it is vital to deliver the appropriate light dose and photosensitizer concentration, and to monitor the PDT dose delivered at the site of interest. In vivo monitoring of photosensitizers has in large part relied on their fluorescence emission. Palladium-containing photosensitizers have shown promising clinical results by demonstrating near full conversion of light to PDT activity at the cost of having undetectable fluorescence. We demonstrate that, through the coupling of plasmonic nanoparticles with palladium-photosensitizers, surface-enhanced Raman scattering (SERS) provides both reporting and monitoring capability to otherwise quiescent molecules. Nano-enabled SERS reporting of photosensitizers allows for the decoupling of the therapeutic and imaging mechanisms so that both phenomena can be optimized independently. Most importantly, the design enables the use of the same laser wavelength to stimulate both the PDT and imaging features, opening the potential for real-time dosimetry of photosensitizer concentration and PDT dose delivery by SERS monitoring.

Keywords: Porphyrins, SERS, Theranostics, Nanoparticles, PDT, Dosimetry