Surface-Engineered Selenium Nanoparticles with L-Asparagine and Tartaric Acid: Therapeutic Efficacy Against Breast...

Selenium nanoparticles (SeNPs), compared to other forms of selenium, have shown promising antioxidant and anticancer properties with lower toxicity. However, SeNPs precipitate and aggregate in aqueous solutions due to their high surface energy. To overcome this limitation and improve stability, solubility, and enhance biological efficacy, we functionalized them with L-asparagine/tartaric acid (Asn-Tar). This study aimed to evaluate the antimicrobial, cytotoxic, and antioxidant properties of SeNPs conjugated to Asn-Tar on MDA-MB-231 breast cancer cells.

This study was conducted at Lorestan, Iran, in 2023. SeNPs were synthesized using a co-precipitation method and then coated with Asn-Tar. Structural characterization was performed using Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Dynamic light scattering (DLS), zeta potential analysis, and Ultraviolet-visible (UV-Vis) spectroscopy. Antioxidant activity was assessed. For biological evaluation, an in vitro experimental design was employed. Cytotoxicity against MDA-MB-231 breast cancer cells and normal fibroblast cells at various pH levels was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with three independent replicates per concentration (n=3). Antimicrobial activity against a panel of Gram-positive and Gram-negative bacteria, including antibiotic-resistant strains, was evaluated in triplicate using broth microdilution and well diffusion methods. Quantitative data are presented as mean±SD. Statistical significance was determined using Student's t test and one-way ANOVA, with P<0.05 considered significant.

The synthesized Asn-Tar/SeNPs nanocomposite exhibited a spherical morphology with an average size of 460.8 nm, a negative zeta potential (-9.37±0.44 mV), and successful coating was confirmed by FTIR and XRD. The nanocomposite demonstrated dose-dependent antioxidant activity, with an IC₅₀ of 22.73±1.55 µg/mL in the DPPH assay. It exhibited potent and selective cytotoxicity against MDA-MB-231 breast cancer cells (IC₅₀=3.47±0.28 µg/mL) compared to normal fibroblast cells (IC₅₀=5.91±0.34 µg/mL; P=0.0051). The nanocomposite retained approximately 50% of its cytotoxic activity at acidic pH (4.5). Furthermore, it showed strong antimicrobial activity, with inhibition zones up to 36.9±1.2 mm against Staphylococcus saprophyticus and MIC values as low as 0.035 mg/mL against Pseudomonas aeruginosa.

The produced Asn-Tar/SeNPs nanocomposite exhibited potent antimicrobial, selective cytotoxicity, and antioxidant properties. Our findings confirm the potential of these Asn-Tar/SeNPs nanocomposites for targeted therapy of breast cancer.