Magneto low-density nanoemulsion (MLDE): A potential vehicle for combined hyperthermia and photodynamic therapy to treat cancer selectively

In this paper, we introduce a new drug delivery system (DDS) called magneto low-density nanoemulsion (MLDE), which can carry maghemite nanoparticles and Chlorin e6 as an active photosensitizer drug. This design can enhance tumor damage after minor heat dissipation and/or minimum visible light photosensitization doses by classical magnetic hyperthermia (MHT) and photodynamic therapy (PDT), respectively. We establish protocols to prepare the MLDE and to load the drug combination onto it. The MLDE prepared herein is nanometric ( < 200 nm), has high encapsulation efficiency, and is stable for at least 12 months in water dispersions. Flow cytometry results demonstrated that MLDE presents targeted selectivity toward the MCF-7 breast cancer cell line but not in NHI-3T3 mouse fibroblast cell lines, because the MCF-7 cancer cell surface contains overexpressed low density lipoprotein (LDL) receptors. Despite this targeted effect, MHT or PDT alone does not prompt significant antiproliferative outcomes. On the other hand, MHT and PDT in combination induce a strong and synergic action on MCF-7 cells and reduce the cell viability. In conclusion, the developed MLDE deserves further investigation because it is biocompatible, displays good encapsulation efficiency, and is highly stable. Moreover, it is selectively taken up by cancer cell surfaces with receptor recognition based on LDL receptor overexpression, which potentiates the action of combined MHT and PDT.