The in vitro photocytotoxicity of photosensitizer encapsulated by nanovehicles comprising biomimetic phospholipids.

Abstract

Photosensitizers (PSs) for use in antimicrobial photodynamic therapy (aPDT) are often characterized by poor solubility and a tendency to aggregate in aqueous environments. Mixed nanomicellar drug delivery systems based on Pluronics block copolymers and biomimetic phospholipids (Colalipids) may enhance the efficiency of photosensitizers. The aim of the present work was to explore a mixed nano-micellar drug delivery composed of Pluronic P123 and three different biomimetic phospholipids (Colalipids). Interactions between the PSs and P123/ Colalipids assemblies were studied at micromolar concentration by means of UV-Vis absorption spectrometry and by photon correlation spectroscopy. The prepared nanocarriers efficiently solubilized model PS precluding its aggregation in aqueous media. P123/Colalipid assemblies formed small, positively charged micelles that efficiently delivered PS to fungal cells leading to cell death following exposure to blue light in vitro. It was found that mixed micelles based on short and medium chain phospholipids caused higher fungal cell reduction as compared to their long chain counterpart. The clinically relevant, CA2 strain was more resistant to aPDT in vitro treatment, as compared to model ATCC strain. However the treatment with optimized formulation caused 6 log CFU reduction of cell survival in CA2 cultures upon light activation.