Selenium nanoparticles stabilized with sodium laureth sulfate: Synthesis, characterization, antibacterial activity, toxicity, and potential use in detergent formulations

Abstract

Current detergents lack single-component colloidal systems combining cleansing, antibacterial efficacy, and environmental safety within stable surfactant-nanoparticle dispersions. We hypothesized that sodium laureth sulfate (SLES) could form stable colloidal complexes with selenium nanoparticles (SeNPs) to create a multifunctional additive. Novel SLES-SeNPs (15–40 nm spheres) were synthesized and optimized using 0.18 mol/L H2SeO3, 0.022 mol/L SLES, and 1.6 mol/L ascorbic acid. Quantum chemical modeling confirmed robust Se-O-Na bonding (ΔE = -2400 kcal/mol) enabling pronounced colloidal stability: ζ-potential of −43.6 mV; stable across pH 2–12 and detergent ions Na⁺, Ba²⁺, Cl⁻, while Fe³ ⁺, SO42⁻, and PO43⁻ induced predictable coagulation per the Schulze-Hardy rule. SLES-SeNPs delivered potent S. aureus inhibition (35 mm zone at 0.018 mol/L) via membrane rupture and selenium accumulation, enhanced detergent washability (94.7% vs 89.5% for the control), viscosity (+8%), and reduced surface tension (-22%), achieved complete surface sterility (<1 CFU/mL on all plates). Most significantly, a low-dose (≤1.8 ×10⁻⁵ mol/L) doubled P. caudatum survival under H₂O₂/ethanol stress – an unprecedented selective toxicity profile for stable colloidal detergent systems. Thus, SLES-SeNPs represent a promising multifunctional additive for detergent formulations, effectively combining enhanced cleaning performance with strong antibacterial activity and a favorable environmental safety profile at use concentrations. These results support the potential for the development of more effective and sustainable cleaning products.