Preparation Of Selenium Nanoparticles Regulated By Walnut Protein Hydrolysates And Its Augmented Anticancer Efficacy

Selenium(Se) is a necessary trace element for the human’s health. Recently, with the increasing developments achieved on the study of physiological effects of Se, Se and its compounds are attracting attentions. Once the particle size of Se arrives at nanometer scale, it will form into colloid with good stability, which has both the biological activities of Se and the effects of nanoscale. Se nanoparticles(SeNPs) belong to inorganic substances. SeNPs have the characterizations of high activities and low toxicities, showing a great potential in the cancer prevention, cancer treatment, and reducing of drug resistance.Protein hydrolysates are compatible to be used as template regulating agents to prepare nano materials. Protein hydrolysates are characterized with low energy consumption, fast transportation, and hardly being saturated. In addition, protein hydrolysates have great nutrition functions: improving the utilization of amino acids, promoting the synthesis of proteins, and promoting the absorbance of mineral elements. This paper reported a facile synthesis of degreased walnut protein hydrolysates functionalized SeNPs hybrids with enhanced anticancer activity and a detailed mechanistic evaluation of its superior anticancer activity. The main contents and conclusions are as follows:1. The enzymatic preparation and separation of walnut protein hydrolysates(WP)The hydrolysates of WP were prepared using enzymolysis method which chooses the index of protein recovery and degree of hydrolysis as screening factors. The results showed that the optimum enzyme concentration of trypsin was 2% and the optimum hydrolysis time was 30 h. The protein recovery and degree of hydrolysis of walnut protein hydrolysates are 43.97% and 22.96%, respectively. Then, the hydrolysates were separated by ultrafiltration membrane to obtain the component > 10000 u. After lyophilization, the WP was obtained to prepare SeNPs.2. The preparation and characterizations of WP-SeNPsIn the reaction system of ascorbic acid(Vc) and sodium selenite, 3 mg/m L of WP was used as regulating agent to prepare monodisperse and homogeneous spherical SeNPs with an average diameter of 89.22 nm. Particle size analyser, SEM, EDX, and FTIR revealed that the structural characterizations of SeNPs were effectively capped with WP via the formation of Se-O and physical absorption, both of which prevented the further aggregation of SeNPs.3. The antiproliferative activity of WP-SeNPsMTT method demonstrated that human breast adenocarcinoma cells(MCF-7) was the highest susceptible to WP-SeNPs. Further studies revealed that WP-SeNPs could induce the cell shrinking, nuclear condensation, DNA breakage, and accumulation of arrested S phase cells of MCF-7. Careful investigations revealed that an extrinsic apoptotic pathway can be attributed to the cell apoptosis and the same was confirmed by activation of the Fas-associated with death domain(FADD) protein and caspases 3, 8, and 9. In addition, it was also understood that intrinsic apoptotic pathways including ROS generation, as well as the reduction in mitochondrial membrane potential, are also involved in the WP-SeNPs induced apoptosis.