Synthesis, Characterization, and Assessment of Anti-Cancer Potential of ZnO Nanoparticles in an In Vitro Model of Breast Cancer

Abstract

Advanced innovations for combating variants of aggressive breast cancer and overcoming drug resistance are desired. In cancer treatment, ZnO nanoparticles (NPs) have the capacity to specifically and compellingly activate apoptosis of cancer cells. There is also a pressing need to develop innovative anti-cancer therapeutics, and recent research suggests that ZnO nanoparticles hold great potential. Here, the in vitro chemical effectiveness of ZnO NPs has been tested. Zinc oxide (ZnO) nanoparticles were synthesized using Citrullus colocynthis (L.) Schrad by green methods approach. The generated ZnO was observed to have a hexagonal wurtzite crystal arrangement. The generated nanomaterials were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-visible spectroscopy. The crystallinity of ZnO was reported to be in the range 50-60 nm. The NPs morphology showed a strong absorbance at 374 nm with an estimated gap band of 3.20 eV to 3.32 eV. Microscopy analysis proved the morphology and distribution of the generated nanoparticles to be around 50 nm, with the elemental studies showing the elemental composition of ZnO and further confirming the purity of ZnO NPs. The cytotoxic effect of ZnO NPs was evaluated against wild-type and doxorubicin-resistant MCF-7 and MDA-MB-231 breast cancer cell lines. The results showed the ability of ZnO NPs to inhibit the prefoliation of MCF-7 and MDA-MB-231 prefoliation through the induction of apoptosis without significant differences in both wild-type and resistance to doxorubicin.

Keywords: anti-cancer therapy; green synthesis; nanomedicine; triple negative; zinc oxide nanoparticles.

Figure 1

UV-vis spectrum of the generated and rigorously purified ZnO NPs Citrullus colocynthis (L.) Schrad leaves extract suspended in aqueous solution as measured at ambient temperature with a single peak corresponding to the generation of ZnO NPs with maximum absorbance at λ₃₇₄ nm. The spectrum suggests a complete reduction of Zn cations using leaf extract, and the generated NPs were formed regardless of the concentration of plant extract added to the reaction mixture.

Figure 2

Characterization of ZnO NPs. (A) representative histogram of the size (diameter) distribution by the number of ZnO nanoparticle (B) A video frame of nanotracker analysis (NTA) with a single peak measurement and an average of 53 ± 3.5 nm without any visual aggregations.

Figure 3

Representative TEM (A) and SEM (B) images indicate the formation of spherical nanoparticles using the green synthesis approach with a particle size between 50–60 ± 5 nm in diameter. SEM analysis further confirmed that the 3D arrangement of the generated particles was spherical with monodisperse particle distribution.

Figure 4

High-resolution TEM images (A) confirming the crystallinity of the generated particles using the green synthesis approach, (B) selected area diffraction (SAED) diffraction pattern of ZnO nanoparticles.

Figure 5

Dose–response curves. (A) Dose–response curve with IC50 of MCF-7/WT and MCF-7/DR cells after treatment with different concentrations of ZnO NPs for 72 h using the MTT assay. (B) Dose–response curve with IC50 of MDA-MB-231/WT and MDA-MB-231/DR cells after treatment with different concentrations of ZnO NPs for 72 h using the MTT assay (n = 3).

Figure 6

Flow cytometric analysis of the cell death modality. Breast cancer cell lines: MCF-7/WT MCF-7/DR, MDA-MB-231/WT, and MDA-MB-231/DR cells were treated 24 h with 10 µg/mL ZnO NPs and stained with FITC-conjugated annexin V and PI-stained, compared to the untreated control cells. (A,B). Average (%) of apoptotic and necrotic cells after treatment. (C,D) The quadrants in the dot plot indicate viable cells (lower left quadrant), early apoptotic cells (lower right quadrant), necrotic cells (upper left quadrant), and late apoptotic cells (upper right quadrant) (n = 3).