Photochemical internalization of gold(III) complexes into tumor cells through liposomes containing Mg(II) porphyrazine

Photochemical Internalization (PCI) is a technique that uses light to activate photosensitizers in endosomal membranes, facilitating the release of therapeutic agents directly into the cytoplasm of target cells. This study evaluated the potential of associating a magnesium(II) porphyrazine (MgPz) with a gold(III) complex (C3b) in liposomes, aiming to increase selectivity and therapeutic efficiency against breast cancer cells. The liposomal formulation showed an encapsulation rate of 70.9% for the gold complex. Cell viability tests in A431 cell lines revealed that the formulation with the C3b complex alone showed moderate cytotoxicity independent of light, and that the complete formulation (MgPz + C3b) showed a significant increase in toxicity, especially under irradiation. However, the results suggest that the observed toxicity was mainly driven by MgPz. Therefore, further studies are needed to optimize concentrations and ensure that porphyrazine acts effectively on the intracellular release of C3b.