Local Monitoring of Photosensitizer Transient States Provides Feedback for Enhanced Efficiency and Targeting Selectivity in Photodynamic Therapy.

This folder contains all raw data underlying the results presented in a manuscript, accepted for publication in Scientifc Reports, entitled:

Local Monitoring of Photosensitizer Transient States Provides Feedback for Enhanced Efficiency and Targeting Selectivity in Photodynamic Therapy.

Authored by:

Elin Sandberg ¹, Chinmaya V Srambickal ¹, Joachim Piguet ¹, Haichun Liu ¹ and Jerker Widengren ^1,*

¹ Experimental Biomolecular Physics, Department of Applied Physics, Royal Institute of Technology (KTH), Stockholm, Sweden

^*  To whom correspondence should be addressed. Email: jwideng@kth.se. Tel: +46-8-7907813

The data files are grouped with respect to the figures/tables in the manuscript where the extracted results are presented.

ABSTRACT

Photodynamic therapy (PDT) fundamentally relies on local generation of PDT precursor states in added photosensitizers (PS), particularly triplet and photo-radical states. Monitoring these states in situ can provide important feedback but is difficult in practice. The states are strongly influenced by local oxygenation, pH and redox conditions, often varying significantly at PDT treatment sites. To overcome this problem, we followed local PDT precursor state populations of PS compounds, via their fluorescence intensity response to systematically varied excitation light modulation. Thereby, we could demonstrate local monitoring of PDT precursor states of methylene blue (MB) and IRdye700DX (IR700), and determined their transitions rates under different oxygenation, pH and redox conditions. By fiber-optics, using one fiber for both excitation and fluorescence detection, the triplet and photo-radical state kinetics of locally applied MB and IR700 could then be monitored in a tissue sample. Finally, potassium iodide and ascorbate were added as possible PDT adjuvants, enhancing intersystem crossing and photoreduction, respectively, and their effects on the PDT precursor states of MB and IR700 could be locally monitored. Taken together, the presented procedure overcomes current methodological limitations and can offer feedback, guiding both excitation and PDT adjuvant application, and thereby more efficient and targeted PDT treatments.