Novel BODIPY dyes and photosensitized nanoparticles for photodynamic therapy (PDT)

DIPC Seminars

Virginia Martinez Martinez
Universidad del Pais Vasco-EHU
On-side Seminar: Donostia International Physics Center
Luca Salassa
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Novel BODIPY dyes and photosensitized nanoparticles for photodynamic therapy (PDT)

Photodynamic therapy (PDT) is a minimally invasive procedure in which under suitable light irradiation a sensitive drug (photosensitizer, PS) is activated and generates Reactive Oxygen Species (ROS), mainly singlet oxygen (1O2), a cytotoxic species able to damage the nearby cells, virus or bacteria. For that, the number of research to implement this therapy against cancer diseases and/or as antimicrobials has increased in the last few years. However, although nowadays there are many different photosensitizers most of them are not adequate for their biomedical use because of their poor aqueous solubility or their lack of selectivity for their area of interest. Nowadays, a huge effort is devoted in the development of the third generation of PSs to enhance PDT efficiency. One strategy is based on the design of new operative PSs and the second strategy is based on the use of nanoparticles (NPs) as carriers for PS.
This talk will be divided in two main parts related with the first and the second strategies:
- The primary will deal the development of new PS based on the BODIPY chromophore. BODIPY is transformed into excellent photosensitizers via different approaches to enhance the probability of intersystem crossing (ISC) process: by the addition of heavy atoms, i.e. iodine atoms (Halogenated BODIPYs), or by attaching electron-donor groups (heavy atom-free BODIPYs) to activate intramolecular charge transfer states. The photophysical properties of the BODIPY chromophores are fully characterized. Moreover, their viability to internalize into the cells, their phototoxic action under suitable irradiation and cytotoxic effects in dark conditions are also tested in some cases by in vitro assays.
- In the second part, three different nanosystems as PS nanocarriers will be presented: Mesoporous Silica Nanoparticles (MSN), Laponite-nanoclay (LAP) and cellulose nanocrystals (CNC). These carriers were decorated not only with the PS but also with other molecules of interest; polyethylene glycol (PEG) and folic acid (FA) or a gluconamide to improve the stability of nanocarriers and the selectivity to cancer cells or bacteria, respectively. The final hybrid nanosystems show high singlet oxygen generation as well as fluorescence capacity, well stability and selectivity were tested in vitro in HeLa cells and E. Coli bacteria to demonstrate their viability for bioimaging and under specific irradiation and their viability to be used in PDT.

Host: Luca Salassa