Synergistic effect of cold atmospheric plasma and methylene blue loaded nano micelles on treating human glioblastoma cells: An in vitro and molecular dynamics study.

Abstract

Objectives: One of the most recent cancer treatment methods is cold atmospheric plasma (CAP), which destroys cancer cells without affecting healthy cells. Also, the created photons in the CAP flame can be used to excite a proper photosensitizing agent (PS). Therefore, using nano micelle systems containing a proper photosensitizer may be beneficial in raising the treatment efficacy of CAP. In this study, we utilized molecular dynamics (MD) simulation to optimize a nano micellar system containing methylene blue to take advantage of the induced photodynamic effect of a CAP generator with helium gas on a glioblastoma cell line.

Materials and methods: Some micelle properties were first determined and optimized by MD with GROMACS software. Then, micelles containing methylene blue (Micelle-MB) and free methylene blue (MB) at various concentrations were prepared. Singlet oxygen dosimetry using 1,3-diphenylisobenzofuran (DPBF)was performed in the presence and absence of Micelle-MB and MB. Subsequently, the cytotoxicity of MB and Micelle-MB was evaluated on U87-MG cancer cells, and their half-maximal inhibitory concentrations (IC₅₀) were determined. After 48 hr of treatment, the percentage of cell survival was determined using the MTT test. The experiments were repeated at least three times. The synergy index was selected to compare the results.

Results: Treatment with CAP and MB reduced the survival rate compared to the PS-free group with CAP. Results of singlet oxygen dosimetry showed that Micelle-MB might be more efficient in producing ROS. CAP treatment with Micelle-MB resulted in more cell death than free MB. In addition, cell viability decreased in Micelle-MB groups with increasing irradiation time in the three investigated irradiation times.

Conclusion: Using Micelle-MB in the CAP treatment improves treatment efficiency in the U87-MG cell line.