Human neural stem cells promote proliferation of endogenous neural stem cells and enhance angiogenesis in ischemic rat brain

Transplantation of human neural stem cells into the dentate gyrus or ventricle of rodents has been reportedly to enhance neurogenesis. In this study, we examined endogenous stem cell proliferation and angiogenesis in the ischemic rat brain after the transplantation of human neural stem cells. Focal cerebral ischemia in the rat brain was induced by middle cerebral artery occlusion. Human neural stem cells were transplanted into the subventricular zone. The behavioral performance of human neural stem cells-treated ischemic rats was significantly improved and cerebral infarct volumes were reduced compared to those in untreated animals. Numerous transplanted human neural stem cells were alive and preferentially localized to the ipsilateral ischemic hemisphere. Furthermore, 5-bromo-2′-deoxyuridine-labeled endogenous neural stem cells were observed in the subventricular zone and hippocampus, where they differentiated into cells immunoreactive for the neural markers doublecortin, neuronal nuclear antigen Neu N, and astrocyte marker glial fibrillary acidic protein in human neural stem cells-treated rats, but not in the untreated ischemic animals. The number of 5-bromo-2′-deoxyuridine-positive ？ anti-von Willebrand factor-positive proliferating endothelial cells was higher in the ischemic boundary zone of human neural stem cells-treated rats than in controls. Finally, transplantation of human neural stem cells in the brains of rats with focal cerebral ischemia promoted the proliferation of endogenous neural stem cells and their differentiation into mature neural-like cells, and enhanced angiogenesis. This study provides valuable insights into the effect of human neural stem cell transplantation on focal cerebral ischemia, which can be applied to the development of an effective therapy for stroke.

Ultra-flexible semitransparent organic photovoltaics

Ultra-flexible organic photovoltaics(OPVs)are promising candidates for next-generation power sources owing to their low weight,transparency,and flexibility.However,obtaining ultra-flexibility under extreme repetitive mechanical stress while maintaining optical transparency remains challenging because of the intrinsic brittleness of transparent electrodes.Here,we introduce straindurable ultra-flexible semitransparent OPVs with a thickness below 2μm.The conformal surface coverage of nanoscale thin metal electrodes(<10 nm)is achieved,resulting in extremely low flexural rigidity and high strain durability.In-depth optical and electrical analyses on ultrathin metal electrodes showed that the devices maintain over 73%of their initial efficiency after 1000 cycles of repetitive compression and release at 66%compressive strain,and the average visible light transmittances remain higher than 30%.To our knowledge,this is the first systematical study on mechanical behaviors of strain-durable ultra-flexible ST-OPVs through precise adjustment of each ultrathin electrode thickness toward the emergence of next-generation flexible power sources.

High entropy spinel oxide for efficient electrochemical oxidation of ammonia

Ammonia has emerged as a promising energy carrier owing to its carbon neutral content and low expense in long-range transportation.Therefore,development of a specific pathway to release the energy stored in ammonia is therefore in urgent demand.Electrochemical oxidation provides a convenient and reliable route to attain efficient utilization of ammonia.Here,we report that the high entropy(Mn,Fe,Co,Ni,Cu)_(3)O_(4)oxides can achieve high electrocatalytic activity for ammonia oxidation reaction(AOR)in non-aqueous solutions.The AOR onset overpotential of(Mn,Fe,Co,Ni,Cu)_(3)O_(4)is 0.70 V,which is nearly 0.2 V lower than that of their most active single metal cation counterpart.The mass spectroscopy study reveals that(Mn,Fe,Co,Ni,Cu)_(3)O_(4)preferentially oxidizes ammonia to environmentally friendly diatomic nitrogen with a Faradic efficiency of over 85%.The Xray photoelectron spectroscopy(XPS)result indicates that the balancing metal d-band of Mn and Cu cations helps retain a longlasting electrocatalytic activity.Overall,this work introduces a new family of earth-abundant transition metal high entropy oxide electrocatalysts for AOR,thus heralding a new paradigm of catalyst design for enabling ammonia as an energy carrier.

Biocompatible custom ceria nanoparticles against reactive oxygen species resolve acute inflammatory reaction after intracerebral hemorrhage

Intracerebral hemorrhage （ICH） is a devastating subtype of stroke with a high mortality rate, for which there currently is no effective treatment. A perihematomal edema caused by an intense inflammatory reaction is more deleterious than the hematoma itself and can result in neurological deterioration and death. Ceria nanoparticles （CeNPs） are potent free radical scavengers with potential for biomedical applications. As oxidative stress plays a major role in post-ICH inflammation, we hypothesized that CeNPs might protect against ICH. To test this hypothesis, core CeNPs were synthesized using a modified reverse micelle method and covered with phospholipid-polyethylene glycol （PEG） to achieve biocompatibility. We investigated whether our custom-made biocompatible CeNPs have protective effects against ICH. The CeNPs reduced oxidative stress, hemin-induced cytotoxicity, and inflammation in vitro. In a rodent ICH model, intravenously administered CeNPs were mainly distributed in the hemorrhagic hemisphere, suggesting that they could diffuse through the damaged blood-brain barrier. Moreover, CeNPs attenuated microglia/macrophage recruitment around the hemorrhagic lesion and inflammatory protein expression. Finally, CeNP treatment reduced the brain edema by 68.4% as compared to the control. These results reveal the great potential of CeNPs as a novel therapeutic agent for patients with ICH.

Customized lipid-coated magnetic mesoporous silica nanoparticle doped with ceria nanoparticles for theragnosis of intracerebral hemorrhage

Intracerebral hemorrhage （ICH）, caused by the sudden rupture of an artery within the brain, is a devastating subtype of stroke, which currently has no effective treatment. Intense inflammatory reactions that occur in the peri-hematomal area after ICH are more deleterious than the hematoma itself, resulting in subsequent brain edema and neurologic deterioration. Thus, we developed lipid-coated magnetic mesoporous silica nanoparticles doped with ceria nanoparticles （CeNPs）, abbreviated as LMCs, which have both potent anti-inflammatory therapeutic effects via scavenging reactive oxygen species and help in increasing the efficacy of magnetic resonance imaging enhancement in the peri-hematomal area. LMCs consist of mesoporous silica nanopartide-supported lipid bilayers, which are loaded with large amounts of CeNPs for scavenging of reactive oxygen species, and iron oxide nanoparticles for magnetic resonance imaging contrast. LMCs loaded with CeNPs exhibited strong anti-oxidative and anti-inflammatory activities in vitro. In the rodent ICH model, intracerebraUy injected LMCs reached the peri-hematomal area and were engulfed by macrophages, which were clearly visualized by magnetic resonance imaging of the brain. Moreover, LMCs reduced inflammatory macrophage infiltration, and thus significantly reduced brain edema. Finally, LMC treatment markedly improved neurologic outcomes of the animals with ICH. Thus, LMC is the first nanobiomaterial that successfully showed theragnostic effects in ICH.