Facet control of ceria nanocrystals synthesized by an oleate-modified hydrothermal method

Hybrid Lipoplex Boosts Neuron-Microglia Crosstalk for Treatment of Alzheimer's Disease through Aβ-Targeted-Autophagy and ApoE2 Gene Supplementation

Efficient clearance of amyloid-β (Aβ) is vital but challenging in Alzheimer's disease (AD) treatment due to its complicated regulation mechanisms during generation and metabolism. It necessitates a multidimensional synergistic strategy based on ingenious delivery system design. Herein, guanidine-rich lipids (metformin-inspired MLS and arginine-contained RLS) are devised to trigger selective chaperone-mediated autophagy for amyloid precursor protein degradation in neurons. They are further co-assembled with oleic acid-modified cerium dioxide (OA@CeO2) to form RMC assembly for pApoE2 delivery (RMC/pApoE2 lipoplex). The OA@CeO2 boosts macro-autophagy, alleviates oxidative stress and inflammatory microenvironment, and promotes the neurons-microglia crosstalk for Aβ elimination. Concurrently, both guanidine-rich lipids and OA@CeO2 benefit pApoE2 transfection in neurons, enabling the transport of Aβ into microglia, and facilitating enzymatic hydrolysis and cellular digestion of extracellular Aβ. The lipoplex-boosted neuron-microglia interactions ultimately eliminate both intra- and extra-cellular Aβ aggregates. Consequently, the RMC/pApoE2 lipoplex eliminates ≈86.9% of Aβ plaques in the hippocampus of APP/PS1 mice and restored the synaptic function and neuronal connectivity. Moreover, it recovers the spatial memory of APP/PS1 mice to nearly the level of WT control. The presented hybrid lipoplex showcases an advanced gene delivery system, and offers a promising strategy for Aβ clearance in AD treatment.

Ionic Conductivity of Electrolytes Composed of Oleate-Capped Yttria-Stabilized Zirconia Nanoparticles

Yttria-stabilized zirconia (YSZ) is a highly promising electrolyte material for solid oxide fuel cells (SOFCs). We investigated the conductivity-enhancing effect of nanosized YSZ to explore key techniques to decrease the operating temperature. YSZ nanoparticles ranging from 2 to 4 nm were synthesized with oleate groups by the hydrothermal method at various oleate/metal ion ratios (Ole/M = 1.00, 0.75, and 0.50). The nanoparticles were sintered, and the ionic conductivities were evaluated. The 1.00 Ole/M sample exhibited high dispersibility in cyclohexane and showed a nearly monodispersed distribution. The other samples possessed agglomerated nanoparticles. The sintered YSZ nanoparticles had densities of 3.36-2.80 g/cm3 and ionic conductivities of 2.52-1.16 mS/cm at 750 °C, which are higher than those of commercial 8 mol % YSZ. Furthermore, the sintered YSZ nanoparticles exhibited higher activation energies than the commercial samples in the lower temperature range (550-650 °C). The ionic conductivity enhancement despite the high activation energy is likely due to the increased grain boundary volume. This study demonstrated the successful production of YSZ with high ionic conductivity and sinterability upon sintering at 1050 °C using YSZ nanoparticles.

Anisotropic growth of gas–liquid precipitated ceria mesocrystals to wires several micrometers in length

Ceria (CeO₂) wires with lengths of 6 μm and diameters of tens of nanometers are fabricated through the anisotropic growth of mesocrystals. In the gas–liquid precipitation process, an aqueous Ce(NO₃)₃ solution is used as a starting material and NH₃ gas is used to induce CeO₂ precipitation at the gas–liquid interface. CeO₂ mesocrystals, formed by this process at 60 °C, grow in the direction of 〈011〉 into micrometer length wires exposing {001} and {011} on their side walls. It is shown that the initial pH of the starting material solution is a key parameter to attain anisotropic growth of the CeO₂ mesocrystals. We thus propose the formation mechanism of micrometer length-CeO₂ wires from mesocrystals.

CeO₂ wires several micrometers in length were formed through anisotropic growth of mesocrystals by oriented attachment on {111} surfaces.

Impact of the synthesis parameters on the solid state properties and the CO oxidation performance of ceria nanoparticles

A direct quantitative correlation of surface-to-bulk (O_s/O_b) reducible oxygen of ceria nanoparticles (NPs) with catalytic activity was revealed.