Three new biocompatible porphyrin-based oxygen photosensitisers were tested in vitro on breast cancer cells via 2P-PDT: one of them, 66 times more active than H₂TPP, gave quite promising results for theranostic applications.

Mesoporous organosilica nanoparticles (PHT-PMO) have been prepared from an octa-triethoxysilylated Zn phthalocyanine precursor. These PHT-PMO nanoparticles had no dark toxicity but high phototoxicity when irradiated at 650 nm, and remarkable near-infrared phototoxicity when excited at 760 and 810 nm. The PHT-PMO were then aminated to promote electrostatic complexation with siRNA. Transfection experiments were performed upon NIR irradiation and photochemical internalization was very efficient, leading to 65% luciferase extinction in MCF-7 cancer cells expressing stable luciferase.

The aim of the present work is the development of highly efficient targeting molecules to specifically address mesoporous silica nanoparticles (MSNs) designed for the photodynamic therapy (PDT) of prostate cancer. We chose the strategy to develop a novel compound that allows the improvement of the targeting of the cation-independent mannose 6-phosphate receptor, which is overexpressed in prostate cancer. This original sugar, a dimannoside-carboxylate (M6C-Man) grafted on the surface of MSN for PDT applications, leads to a higher endocytosis and thus increases the efficacy of MSNs.

Diazachlorin and diazabacteriochlorin have been prepared through reduction of diazaporphyrin and their in vitro and in vivo activity in photodynamic therapy has been investigated.

The discovery of novel anticancer chemotherapeutics is fundamental to treat cancer more efficiently. Towards this goal, two dyads consisting of a gold porphyrin appended to organotin(IV) entities were synthesized and their physicochemical and biological properties were characterized. One dyad contains a gold porphyrin connected to a tin(IV) cation via a malonate and two phenyl ligands (AuP-SnPh₂), while the other contains two tin(IV) cations each chelated to one carboxylic acid group of the malonate and three phenyl ligands (AuP-Sn₂Ph₆). The mode of chelation of Sn(IV) to the malonate was elucidated by IR spectroscopy and ¹¹⁹Sn NMR. In the solid state, the complexes exist as coordination polymers in which the tin is penta-coordinated and bridged to two different malonate units. In solution the chemical shifts of ¹¹⁹Sn signals indicate that the tin complexes are in the form of monomeric species associated with a tetra-coordinated tin cation. The therapeutic potential of these new compounds was assessed by determining their cytotoxic activities on human breast cancer cells (MCF-7) and on healthy human fibroblasts (FS 20-68). The study reveals that the dyads are more potent anticancer drugs than the mixture of their individual components (gold porphyrin and reference tin complexes). Therefore, the covalent link of organotin complexes to a gold porphyrin induces a synergistic cytotoxic effect. The dyad AuP-SnPh₂ shows high cytotoxicity (0.13 μM) against MCF-7 along with good selectivity for cancer cells versus healthy cells. Finally, it was also shown that the dyad AuP-Sn₂Ph₆ exhibits a very high anticancer activity (LC₅₀ = 0.024 μM), but the presence of two tin units induces strong cytotoxicity on healthy cells too (LC₅₀ = 0.032 μM). This study underscores, thus, the potential of the association of gold porphyrin and organotin complexes to develop anticancer metallo-drugs.

The concept of using two‐photon excitation in the NIR for the spatiotemporal control of biological processes holds great promise. However, its use for the delivery of nucleic acids has been very scarcely described and the reported procedures are not optimal as they often involve potentially toxic materials and irradiation conditions. This work prepares a simple system made of biocompatible porous silicon nanoparticles (pSiNP) for the safe siRNA photocontrolled delivery and gene silencing in cells upon two‐photon excitation. PSiNP are linked to an azobenzene moiety, which possesses a lysine group (pSiNP@ICPES‐azo@Lys) to efficiently complex siRNA. Non‐linear excitation of the two‐photon absorber system (pSiNP) followed by intermolecular energy transfer (FRET) to trans azobenzene moiety, result in the photoisomerization of the azobenzene from trans to cis and in the destabilization of the azobenzene‐siRNA complex, thus inducing the delivery of the cargo siRNA to the cytoplasm of cells. Efficient silencing in MCF‐7 expressing stable firefly luciferase with siRNAluc against luciferase is observed. Furthermore, siRNA against inhibitory apoptotic protein (IAP) leads to over 70% of MCF‐7 cancer cell death. The developed technique using two‐photon light allows a unique high spatiotemporally controlled and safe siRNA delivery in cells in few seconds of irradiation.