Ceria nanoparticles boost activity of aged murine oocytes

Oocyte meiotic maturation and viability of follicular granulosa cells in young and old experimental Balb/C and CBA mice in the presence of ceria nanoparticles were studied. Treatment of old Balb/c mice with ceria nanoparticles for three days once a day (at a dose of 45 mg/kg) leads to a positive effect on reproductive system. The number of oocytes in follicles increases and this effect is accompanied by an increase in the number of oocytes at metaphase Ⅰ and metaphase Ⅱ. The number of living granulosa cells increases, while percentage of the necrotic and apoptotic ones decreases relative to control group. Data obtained on CBA mice provided additional evidence for positive effect of ceria nanoparticles. Depending on the initial state of the reproductive system and dose of ceria nanoparticles the effectiveness of the treatment will vary. In case of old mice ceria nanoparticles protect ovarian cells against oxidative damage, working as anti-aging agent. The litter size in old mice treated with the CNs increases too

Control of oxygen vacancies and Ce+3 concentrations in doped ceria nanoparticles via the selection of lanthanide element

The effect of lanthanides that have positive association energies with oxygen vacancies, such as samarium and neodymium, and the elements with negative association energies, such as holmium and erbium, on ionization state of cerium and, consequentially, the oxygen vacancy concentration in doped ceria nanoparticles are investigated in this article. Structural and optical characterizations of the doped and undoped ceria nanoparticles, synthesized using chemical precipitation, are carried out using transmission electron microscopy, X-ray diffractometry, optical absorption spectroscopy, and fluorescence spectroscopy. It is deduced that the negative association energy dopants decrease the conversion of Ce+4 into Ce+3 and, hence, scavenge the oxygen vacancies, evidenced by the observed increase in the allowed direct bandgap, decrease in the integrated fluorescence intensity, and increased the size of doped nanoparticles. The opposite trends are obtained when the positive association dopants are used. It is concluded that the determining factor as to whether a lanthanide dopant in ceria acts as a generator or scavenger of oxygen vacancies in ceria nanoparticles is the sign of the association energy between the element and the oxygen vacancies. The ability to tailor the ionization state of cerium and the oxygen vacancy concentration in ceria has applications in a broad range of fields, which include catalysis, biomedicine, electronics, and environmental sensing