Impact of heat treatment on size, structure, and bioactivity of elemental selenium nanoparticles

Abstract

Background: Elemental selenium nanoparticles have emerged as a novel selenium source with the advantage of reduced risk of selenium toxicity. The present work investigated whether heat treatment affects the size, structure, and bioactivity of selenium nanoparticles. Methods and results: After a one-hour incubation of solution containing 80 nm selenium particles in a 90°C water bath, the nanoparticles aggregated into larger 110 nm particles and nanorods (290 nm × 70 nm), leading to significantly reduced bioavailability and phase II enzyme induction in selenium-deficient mice. When a solution containing 40 nm selenium nanoparticles was treated under the same conditions, the nanoparticles aggregated into larger 72 nm particles but did not transform into nanorods, demonstrating that the thermostability of selenium nanoparticles is size-dependent, smaller selenium nanoparticles being more resistant than larger selenium nanoparticles to transformation into nanorods during heat treatment. Conclusion:The present results suggest that temperature and duration of the heat process, as well as the original nanoparticle size, should be carefully selected when a solution containing selenium nanoparticles is added to functional foods.

Preparation and antioxidant properties of selenium nanoparticles-loaded chitosan microspheres

“…The aggregates comprising numerous single SeNPs were actually dark bulks that appeared during the long-term preservation. However, the narrow size distribution, highly faceted morphology and uniform edge-to-edge distances between particles induced by heating 40 nm SeNPs 38 were not found among these enlarged SeNPs shown in Figure 2C and D. Perhaps, sharp reconstruction of original SeNPs could not be triggered under such a mild storage condition (25°C). However, size enlargement and agglomeration of SeNPs seemed to be unavoidable in an aqueous environment.…”

“…6,17 Obviously, the morphology of SeNPs could be easily mediated by CTS. A smaller size of CTS-SeNPs, however, might be preferred instead of the bigger ones, since better thermostability, 38 more powerful antioxidant activities, 6 and more potent chemopreventive abilities 17 could be achieved.…”

Inverse relationship between elemental selenium nanoparticle size and inhibition of cancer cell growth in vitro and in vivo

“…1A, C). To obtain larger sized SeNPs, the small-sized SeNPs were heated at 70 C for 10 h after Zhang et al (2012), who demonstrated that heat treatment increases SeNP dimensions. The resultant large-sized SeNPs were an average of 91 nm, as indicated by both TEM and DLS (Fig.…”

Selenium and its Role in Higher Plants

“…Otherwise, the thermal stability of Se nanoparticles as a type of nanoscale biomaterial remains unknown. Thus, the thermostability of Se nanoparticles is sizedependent, smaller Se nanoparticles being more resistant than larger Se nanoparticles to transformation into nanorods during heat treatment as reviewed by Zhang et al ( 2012 ).…”