Chitosan polyplex nanoparticle vector for miR-145 expression in MCF-7: Optimization by design of experiment

miR-145, a tumor suppressor micro RNA (miRNA), is down regulated in cancer and can be introduced as a therapeutic agent in various cancers including breast cancer. In this study, miR-145 plasmid was transfected to MCF-7 cells using chitosan polyplex nanoparticles. The vector was prepared according to an optimized fabricating method determined by response surface analysis and D-optimal design. Effects of chitosan molecular weight (Mw) and polymer amine to DNA phosphate ratio (N/P) as the variables were investigated on size, zeta potential, stability, and transfection efficiency of the polyplex nanoparticles. The results indicated that there is an interaction between effects of Mw and N/P ratio on the size of nanoparticles. Gel retardation assay demonstrated that the stability of the complexes in serum and preparation medium during storage time depends on the formulation variables. Statistical analysis affirmed that in spite of particle size, the variables of N/P ratio, time of incubation, and zeta potential affect the gene transfection. In conclusion, by selecting the perfect formulation prepared through an optimized method, it is possible to achieve a high transfection efficacy for miR-145 as an anticancer biological macromolecule.