Starch-Stabilized Selenium Nanoparticles: Synthesis, Purification, Characterization, In Vitro Anticancer and Apoptosis Inducing Evaluation

In order to mitigate drug resistance associated with cancer and minimize adverse effects on healthy cells, it is imperative to explore and develop novel therapeutic alternatives that exhibit enhanced efficacy and safety profiles. This study investigates the potential anticancer effects and apoptosis-inducing properties of some nano-selenium composites on two common types of cancer cells: human breast cancer (MCF-7) and liver carcinoma (HepG-2) cells, as well as their cytotoxic effect on normal retinal pigment epithelium cells (RPE-1). Selenium nanoparticles have been embedded onto starch (SeNP@starch) and then purified by dialysis technique (P-SeNP@starch). The crude and dialyzed SeNPs have been characterized using FTIR, TGA, XRD, ICP-OES, Raman spectroscopy, TEM, size distribution, and zeta potential analysis. ICP-OES results proved the increase of Se concentration in the dialyzed sample than the crude by 32%. XRD pattern confirmed the low crystallinity of the SeNP samples especially for the purified one, while SeNPs are embedded in B-type crystalline starch. Both Raman spectroscopy and TEM supported their nano-size as well as the amorphous form of P-SeNP@starch. Interestingly, zeta potential measurements showed the negatively charged surface of both crude and purified composites, which could increase their affinity towards cancer cells, and in turn, enhance their efficacy. The anticancer activity results demonstrated the cytotoxicity IC₅₀ of the studied compounds against MCF-7 is superior to HepG-2 cancer cells with respect to the IC₅₀ of doxorubicin (standard drug). The IC₅₀ of the SeNP@starch against MCF-7 was 27.4 µg/mL. However, upon purification, the IC₅₀ was improved more than two folds and found to be 11.3 µg/mL. On the other hand, these nanocomposites have better safety therapeutic indices (TI) than the doxorubicin on MCF-7. Cell-cycle analysis and apoptosis assay indicate that the cytotoxic activities of SeNP@starch and P-SeNP@starch are due to their potent pro-apoptotic activity, and generally, P-SeNP@starch induced more apoptotic effect than SeNP@starch. These findings suggest that purified selenium nanoparticles in their amorphous form could have potential as novel anticancer agent against human breast cancer cells.