Optimization of the physiochemical synthesis parameters of the Se/CMC nanocomposite: Antibacterial, antioxidant, and anticancer activity.

Selenium nanoparticles (Se NPs) have gained growing significance due to their remarkable therapeutic qualities, decreased toxicity, enhanced bioavailability, and biocompatibility compared to other selenium compounds. Se NPs were synthesized using ascorbic acid (AA) and carboxymethyl cellulose (CMC) as reducing and capping agents, respectively. This was carried out by optimizing the physiochemical preparation parameters (e.g., precursor salt concentration, AA concentration, temperature, and pH). Characterization of the optimized Se/CMC nanocomposite sample was conducted using several techniques including UV-Vis spectroscopy, FT-IR, X-ray XRD, TEM, SEM, EDX, DLS, and Zeta potential. The UV-Vis spectra results indicate that the synthesized Se/CMC nanocomposite exhibits a most prominent surface plasmon resonance (SPR) peak at λ_max = 270 nm. The diameter of the synthesized Se/CMC nanocomposite varied between 100 and 500 nm as observed in TEM images, and as verified by the DLS technique. Moreover, the Z-potential evaluated for the Se/CMC nanocomposite using the most optimal synthesis conditions was -21.8 ± 4.48 mV. The results obtained showed that Se/CMC nanocomposite had a more significant impact on Gram-negative clinical bacterial isolates (23 ± 0.97 mm) than Gram-positive (22 ± 0.95 mm). Additionally, the synthesized nanocomposite showed a highly antioxidant activity (83 %) of inhibition DPPH free radicals results using DPPH assay. Also, the fabricated Se/CMC nanocomposite has good anticancer activity (168 μg/mL) against the liver HepG2 cell line using MTT assay. Hence, the Se/CMC nanocomposite that was prepared has promising prospects in the field of healthcare owing to its enhanced capacity as an antioxidant, anticancer, and antibacterial agent.