Antimicrobial activity of novel curcumin-based photosensitizer in liposomal form against Staphylococcus aureus strain: in vitro study

Abstract

Photodynamic therapy (PDT) is applied in many medical fields. It is based on photosensitizer (PS) delivery within pathological cells and subsequent irradiation of appropriate laser leading to selective cell death. The creation of such forms of photosensitizers providing most efficient PS delivery into the cell is still relevant. The novel liposomal form which increases the bioavailability of curcumin-based photosensitizer is developed.
Materials and methods.
Antimicrobial activity of PS in liposomal form with curcumin at a concentration of 1% (group I) and 2% (group II) after 445 nm laser exposure against S. aureus strain has been analyzed during the research. The degree of photobleaching of the cell culture was assessed, and the optical density of the microbial mixture was measured after irradiation during 48-hour cultivation.
Results.
The photobleaching level of group II exceeded the threshold of 50% and reached 54.2±0.4%, which is significantly more than 30.2±0.2% for the sample of group I. When cultivating a pure culture the optical density of the microbial suspension at the development point α (10th hour) was 4.3±0.3 MFU, at the development point β (12th hour) — 5±0.3 MFU. When cultivating a sample of group I the optical density of the microbial suspension at the development point α (10th hour) was 3.54 MFU, at the development point β (12th hour) — 4.76 MFU. For group II the optical density of the microbial suspension at the development point α (12th hour) was 3.4 MFU, at the development point β (14th hour) — 4.0 MFU, which is statistically significantly lower than in group I.
Conclusion.
Photoactivation of PS with 2% curcumin in liposomes by laser radiation leads to a more pronounced decrease in the intensity of microorganism growth compared to PS with 1% curcumin. The effect of laser on PS with 2% curcumin triggers more active processes of microbial cell death. The novel liposomal form of PS with curcumin has shown its promise for further investigation and implementation in dental clinical practice.