Mineral-Phytochemical Conjugate: Synthesis, Characterization, Biological Activities and Safety of Nano...

Selenium-curcumin conjugated nanoparticles (curconSeNPs) were synthesized using an ascorbic acid-mediated reduction method to enhance the biofunctional stability of selenium and curcumin nanoforms. Selenium, an essential antioxidant micronutrient, attains improved bioavailability and reduced reactivity at the nanoscale, and its conjugation with curcumin further strengthens these advantages. The synthesized selenium nanoparticles (SeNPs), curcumin nanoparticles (CurNPs), and curconSeNPs were characterized for size distribution, morphology, elemental composition, surface charge, and functional groups. Conjugation reduced the hydrodynamic particle size from 71 nm (SeNPs) to 54 nm, while the optical band gap decreased from 2.13 eV to 1.61 eV, indicating altered electronic properties. SEM, TEM, and SAED analyses confirmed spherical nanoparticles with a rhombohedral crystal structure, and EDAX revealed clear signatures of selenium and oxygen. The lattice fringe spacing measured 5 nm for SeNPs and 10 nm for curconSeNPs. FTIR spectra verified the presence of curcumin and selenium functional groups, and SAED revealed additional biofunctional groups associated with the conjugate. CurconSeNPs exhibited enhanced colloidal stability, with a zeta potential of -35.6 mV compared with - 33 mV for SeNPs and - 12.3 mV for CurNPs. Acute oral toxicity studies in Wistar rats demonstrated a wide safety margin for all formulations, indicating their suitability for future biotherapeutic and nutraceutical applications.