Liposomal Pt(II)- and Au(I)-NHC compounds for photodynamic therapy

Metal-based anticancer agents such as cisplatin and auranofin have inspired the development of platinum- and gold-based complexes, although improving tumor selectivity remains a key challenge. In this work, an Au–NHC complex was synthesized and characterized by NMR, mass spectrometry, UV–Vis spectroscopy, elemental analysis, and X-ray diffraction. Liposomal formulations based on soy phospholipids were developed to enable controlled intracellular drug release. A porphyrazine photosensitizer (0.05–0.5%) was incorporated into the lipid membrane, and its loading was evaluated by UV–Vis spectroscopy. Leakage assays using carboxyfluorescein-loaded liposomes demonstrated that red-light irradiation (620–630 nm) triggered membrane disruption and cargo release. Complete leakage times were similar for most formulations, while liposomes containing 0.05% porphyrazine required more than 20 min for complete rupture. Pt–NHC synthesis is ongoing, and optimized Au–NHC liposomes are undergoing biological evaluation, with preliminary results indicating enhanced selectivity upon irradiation.