Synthesis of Folic Acid-Functionalized Hybrid Mesoporous Silica Nanoparticles and In Vitro Evaluation on MCF-7 Breast Cancer Cells

Folate receptor alpha is expressed at low levels in normal tissues, but is elevated in aggressive breast cancer types and can be utilized for targeted nanoparticle delivery. Hence, we prepared a hybrid nanocarrier based on in-house synthesized mesoporous silica nanoparticles (MSNs) which were further lipid-coated and reinforced with folic acid (FA). Thorough physicochemical evaluation was performed including dynamic light scattering (DLS), powder x-ray diffraction (PXRD), thermogravimetric analysis (TGA), and nitrogen physisorption. In vitro dissolution of the model drug doxorubicin was carried out in release media with pH 7.4 and pH 5.5. The cytotoxic potential and cellular uptake were investigated in MCF-7 breast cancer cells via the MTT assay, doxorubicin fluorescence measurement, and microscopy. The potential amelioration of doxorubicin’s cardiotoxicity was evaluated in vitro on the H9c2 cell line. The results showed MSNs with significant pore volume (1.38 cm3/g) and relatively small sizes (98.05 ± 1.34 nm). The lipid coat and FA attachment improved the physicochemical stability and sustained release pattern over 24 h. MSNs were non-toxic, while when doxorubicin-loaded, they caused moderate cytotoxicity. The highest cytotoxic activity was observed with folate-functionalized, doxorubicin-loaded nanoparticles (NPs). Even though non-loaded folate-functionalized NPs exhibited significant cytotoxicity, their physical mixture with doxorubicin was inferior in MCF-7 cytotoxicity as opposed to the corresponding loaded nanocarrier. Fluorescence-based quantification showed a higher intracellular accumulation of doxorubicin when delivered via NPs. These results demonstrate the potential to use folate-functionalized NPs as carriers for doxorubicin delivery in breast cancer cells. Its cardiotoxicity was significantly reduced in the case of loading onto the folic acid-functionalized lipid-coated MSNs. All these findings provide a promising proof-of-concept, although further experimental validation, particularly regarding targeting selectivity and safety, is required.