ZnO based micro and nanomaterials for breast cancer therapy
Breast cancer is one of the largest causes of women’s death in the world. Millions of women are affected by breast cancer. Despite the significant achievements in breast cancer treatment, some problems, such as damage to healthy tissues and adverse effects including myelosuppression, heart failure, and infertility have been observed in the case of the non-specific systemic delivery of the cytostatic agent. Nanoparticles are gaining attention as a valuable solution to addressing these problems because of their unique characteristics, such as their enhanced permeability and retention in tumor tissue. In this thesis, it is investigated and compared the effect of spherical zinc peroxide (ZnO2) nanoparticles of different sizes, commercially available ZnO nanopowder as well as tetrapodal-shaped ZnO (T-ZnO) microparticles on breast cancer (MCF-7) cells as a function of particle concentration. The cytotoxicity and viability of the different particles were investigated for breast cancer (MCF-7) cells in comparison with normal fibroblasts cells (RMF-EG). The results indicated that ZnO2 nanoparticles of average size between 20 - 80 nm were most effective against MCF-7 cells and showed minimal toxicity to normal fibroblasts (RMF-EG) cells. To better understand the underlying mechanism, we investigated cellular uptake into MCF-7 human breast cancer cells and correlated their uptake with cell death. In summary, it is demonstrated that ZnO2 particles are taken up by MCF7 cells and induced stronger cytotoxic effect in these malignant cells. This suggested their potential clinical advantages (application to reduce side-effects of nonmalignant tissue) in treatment of breast cancer. It was also anticipated that ZnO2 nanoparticles could be used for the development of a pH-sensitive drug delivery system that minimizes drug toxicity.