Porphyrin-Functionalized Porous Silicon Nanoparticles for Photodynamic Therapy

Nanomaterials offer the potential for minimally invasive and focal therapies to reduce side-effects associated with systemic administration of anticancer drugs. Clinical treatment involving photodynamic therapy is particularly attractive since it allows spatial and temporal control of the production of highly cytotoxic singlet oxygen and reactive oxygen species through local excitation of a photosensitizer.

Porous silicon nanoparticles (pSiNP), obtained by electrochemical etching of crystalline silicon followed by ultrasonic treatment, are particularly attractive for nanomedicine because they are bioresorbable in vivo and their degradation product, silicic acid, is non-toxic. In addition pSiNP display intrinsic optical properties (luminescence) deriving from their semi-conductive nature, very usefull for imaging.

Here we will present simple photosensitizer/pSiNP systems based on a porphyrin derivative covalently attached to the nanoparticle, and demonstrate imaging and PDT in vitro under one (OPE) and two photon excitation (TPE) conditions. We will describe the preparation of the biodegradable pSiNP, the chemical functionalization of pSiNP with the photosensitizer by the covalent anchoring of a porphyrin into the porous silicon matrix using a new type of conjugation chemistry, as well as their functionalization with cancer cell targeting species. The targeting and photodynamic efficiency of the described formulations on various cancer cell lines will be presented. We will show that both types of excitation, OPE and TPE, lead to cell death through different excitation pathways.

Emilie Secret, Marie Maynadier, Audrey Gallud, Arnaud Chaix, Elise Bouffard, Magali Gary-Bobo, Nathalie Marcotte, Olivier Mongin, Khaled El Cheikh, Vincent Hugues, Mélanie Auffan, Céline Frochot, Alain Morère, Philippe Maillard, Mireille Blanchard-Desce, Michael J. Sailor, Marcel Garcia, Jean-Olivier Durand and Frédérique Cunin,Two-Photon Excitation of Porphyrin Functionalized Porous Silicon Nanoparticles for Photodynamic Therapy Adv. Mater., 2014, Online. DOI: 10.1002/adma.201403415.

Emilie Secret, Marie Maynadier, Audrey Gallud, Magali Gary-Bobo, Arnaud Chaix, Emmanuel Belamie, Philippe Maillard, Michael J. Sailor,  Marcel Garcia, Jean-Olivier Durand, Frédérique Cunin, Anionic porphyrin-grafted porous silicon nanoparticles for photodynamic therapy, Chem. Commun., 2013, 49(39), 4202-4204. DOI: 10.1039/C3CC38837A