Seminar General
Vineri, 22 Noiembrie 2019, ora 11:00
CETAL, Sala de seminar
Titlu: „Lipid nanocapsules as a multifunctional platform: Towards triggered deep photodynamic therapy”.
Prezintă: Dr. Alexandre BARRAS CNRS, Univ. Lille, Franţa.
Abstract: Photodynamic therapy (PDT) has emerged in recent years as a non invasive therapeutic modality for the treatment of cancers and particularly for the treatment of superficial tumors. PDT is based on the combined use of a photosensitizer (PS), oxygen (O2) and an appropriate light irradiation penetrating tissues. The irradiation triggers a reaction that will produce singlet oxygen (1O2) and/or reactive oxygen species (ROS) and cause a sufficient photodynamic oxidative stress leading to cell death. Due to low solubility of many PSs in aqueous media, aggregates lead to poor phototoxicity activity and cell internalization. These problems can be overcome by nanoencapsulation. Indeed, nanoparticles-based PDT is expected to have several advantages over conventional PDT. Due to the high surface/area ratio of nanocarriers and the possibility to add targets onto their surface, selective targeting toward specific cells can be achieved, limiting the damage of healthy tissues.
We have recently shown that lipid nanocapsules (LNCs) loaded with hypericin, a natural photosensitizer (PS), can be successfully used in PDT experiment in vitro. Moreover, we investigated the possibility to encapsulate two PSs (hypericin and protoporphyrin IX) in a single LNC and their effect towards enhanced PDT in vitro and in vivo.
The depth limitation of classical photodynamic therapy (PDT) with visible or near-infrared light represents also a challenge for the cure of deep tissues or tumors. Taking advantage of LNCs as a multifunctional platform, we have studied the possibility to design lanthanide-based LNCs integrating hypericin for X-ray-induced radio-photodynamic therapy (RPDT). In this case, the gadolinium or the europium luminescence induced by X-ray irradiation plays the role of the local light source to provide singlet oxygen generation for PDT.
