Selenium nanoparticles (SeNPs) have broad application prospects in food preservation and drug development. In this study, grape seed extract (GSE) was used as a natural reducing agent and stabilizer, combined with ascorbic acid (Vc) for the green synthesis of SeNPs (GSE-SeNPs). The preparation process and structural stability were systematically optimized. Response surface methodology (RSM) was employed to optimize the concentrations of Vc and GSE, reaction time, and reaction temperature, aiming to screen out the optimal synthesis conditions with small particle size, good dispersibility, and the smallest PDI value. The results showed that the average particle size of GSE-SeNPs was 74.86 ± 6.07 nm, the PDI was 0.159 ± 0.028, and the Zeta potential was −30.42 ± 0.54 mV, indicating good stability. Characterization results revealed that GSE participated in the reduction and stabilization of SeNPs through electrostatic interactions and hydrogen bonds, forming spherical nanoparticles with a dense structure and good surface organic coating. In addition, GSE-SeNPs exhibited excellent DPPH free radical scavenging ability and antibacterial activity against Staphylococcus aureus in vitro. GSE-SeNPs combine green synthesis, structural stability, and multifunctional biological activities, and have the potential to be used as functional nanomaterials in food preservation and safety fields.

Selenium nanoparticles (SeNPs) have greater bioavailability and safety than inorganic selenium, and was widely used in medical, agricultural, nutritional supplements, and antibacterial fields. The present study screened a strain L11 producing SeNPs from a selenium rich dairy cow breeding base in Hubei Province, China. The strain was identified as Bacillus subtilis through physiological, biochemical, and molecular biology analysis. By adjusting the cultivation conditions, the experiment determined the ideal parameters for L11 to efficiently produce SeNPs. These parameters include a pH value of 6, a cultivation temperature of 37 °C, a concentration of 4 mmol/L Na₂SeO₃, and a cultivation of 48 h. X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), and Transmission Electron Microscopy (TEM) were used to verify that the Se particles produced by L11 are SeNPs with diameters ranging from 50 to 200 nm. The combination of the protein analysis of different cell components and TEM analysis showed that L11 mainly produces SeNPs through the transformation of the cell’s periplasmic space, cell membrane, and cell wall. Adding the L11 SeNPs complex to sheep feed can significantly enhance the antioxidant activity and immunity of sheep, and increase the Se content in the neck muscles, liver, and spleen tissues.

Moderate amounts of Se can promote crop growth, enhance stress resistance, increase yield, and improve nutritional quality. In the present study, kudzu seedlings were used as experimental materials, and their physiological indicators, antioxidant activity, nutritional components, and flavonoid content were measured after being treated with Na₂SeO₃ hydroponics. Transcriptome sequencing analysis was used to reveal the relevant genes involved in regulating the effects of exogenous Se on the content of Se-compounds and flavonoids in kudzu. The results indicated that treatment with 20 mg/L Na₂SeO₃ significantly increased stem and root lengths, dry and fresh weight, lateral root development, and chlorophyll b content. However, at higher concentrations (30–40 mg/L), lateral root abundance and chlorophyll levels decreased. Na₂SeO₃ treatment also augmented the antioxidant capacity and enhanced the content of major nutrients in kudzu seedlings. The total Se content in kudzu escalated with increasing Na₂SeO₃ concentration, with selenomethionine emerging as the primary organic-Se species. After treatment with Na₂SeO₃, the content of puerarin in both aboveground and underground parts decreased, while the content of total flavonoids increased. Daidzin increased in the roots. Differential expression gene analysis revealed that genes such as TRXB2, SYM, MMT1, and METE were involved in Se uptake and transformation in kudzu, while bZIP43 and WRKY47 played a role in flavonoid biosynthesis.

Selenium nanoparticles (SeNPs) has higher bioavailability and safety than inorganic selenium, and was widely used in medical, agricultural, nutritional supplements, and antibacterial fields. The present study screened a strain L11 producing SeNPs from a selenium rich dairy cow breeding base in Hubei Province, China. The strain was identified as Bacillus subtilis through physiological, biochemical, and molecular biology analysis. Through optimization of cultivation conditions, the optimal cultivation parameters for L11 to produce SeNPs were pH=6, cultivation temperature of 37 °C, 4 mmol/L Na2SeO3, and cultivation for 48 hours. XPS, SEM-EDS, and TEM were used to verify that the Se particles produced by L11 are SeNPs with diameters ranging from 50 to 200 nm. The combination of protein analysis of different cell components and TEM analysis showed that L11 mainly produces SeNPs through the transformation of the cell's periplasmic space, cell membrane, and cell wall. Adding L11 SeNPs complex to sheep feed can significantly enhance the antioxidant activity and immunity of sheep, and increase the Se content in the neck muscles, liver, and spleen tissues.