Graphene oxide bulk material reinforced by heterophase platelets with multiscale interface crosslinking.

Graphene oxide (GO) and reduced GO possess robust mechanical, electrical and chemical properties. Their nanocomposites have been extensively explored for applications in diverse fields. However, due to the high flexibility and weak interlayer interactions of GO nanosheets, the flexural mechanical properties of GO-based composites, especially in bulk materials, are largely constrained, which hinders their performance in practical applications. Here, inspired by the amorphous/crystalline feature of the heterophase within nacreous platelets, we present a centimetre-sized, GO-based bulk material consisting of building blocks of GO and amorphous/crystalline leaf-like MnO2 hexagon nanosheets adhered together with polymer-based crosslinkers. These building blocks are stacked and hot-pressed with further crosslinking between the layers to form a GO/MnO2-based layered (GML) bulk material. The resultant GML bulk material exhibits a flexural strength of 231.2 MPa. Moreover, the material exhibits sufficient fracture toughness and strong impact resistance while being light in weight. Experimental and numerical analyses indicate that the ordered heterophase structure and synergetic crosslinking interactions across multiscale interfaces lead to the superior mechanical properties of the material. These results are expected to provide insights into the design of structural materials and potential applications of high-performance GO-based bulk materials in aerospace, biomedicine and electronics.

Polystyrene microplastics lead to pyroptosis and apoptosis of ovarian granulosa cells via NLRP3/Caspase-1 signaling pathway in rats.

Microplastics (MPs) considered as a new persistent environmental pollutant could enter into the circulatory system and result in decrease of sperm quantity and quality in mice. However, the effects of Polystyrene MPs (PS MPs) on the ovary and its mechanism in rats remained unclear. In this present study, thirty-two healthy female Wistar rats were exposed to different concentrations of 0.5 µm PS MPs dispersed in deionized water for 90 days. Using hematoxylin-eosin (HE) staining, the number of growing follicles was decreased compared to the control group. In addition, the activity of glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) were decreased while the expression level of malondialdehyde (MDA) was increased in ovary tissue. Confirmed by immunohistochemistry, the integrated optical density of NLRP3 and Cleaved-Caspase-1 had been elevated by 13.9 and 14 in granulosa cells in the 1.5 mg/kg/d group. Furthermore, compared to the control group, the level of AMH had been decreased by 23.3 pg/ml while IL-1ß and IL-18 had been increased by 32 and 18.5 pg/ml in the 1.5 mg/kg/d group using the enzyme-linked immune sorbent assay (ELISA). Besides, the apoptosis of granulosa cells was elevated measured by terminal deoxyribonucleotide transferase-mediated nick end labeling (TUNEL) staining and flow cytometry. Moreover, western blot assays showed that the expressions of NLRP3/Caspase-1 signaling pathway related factors and Cleaved-Caspase-3 were increased. These results demonstrated that PS MPs could induce pyroptosis and apoptosis of ovarian granulosa cells via the NLRP3/Caspase-1 signaling pathway maybe triggered by oxidative stress. The present study suggested that exposure to microplastics had adverse effects on ovary and could be a potential risk factor for female infertility, which provided new insights into the toxicity of MPs on female reproduction.

An Amorphous Peri-Implant Ligament with Combined Osteointegration and Energy-Dissipation.

Progress toward developing metal implants as permanent hard-tissue substitutes requires both osteointegration to achieve load-bearing support, and energy-dissipation to prevent overload-induced bone resorption. However, in existing implants these two properties can only be achieved separately. Optimized by natural evolution, tooth-periodontal-ligaments with fiber-bundle structures can efficiently orchestrate load-bearing and energy dissipation, which make tooth-bone complexes survive extremely high occlusion loads (>300 N) for prolonged lifetimes. Here, a bioinspired peri-implant ligament with simultaneously enhanced osteointegration and energy-dissipation is presented, which is based on the periodontium-mimetic architecture of a polymer-infiltrated, amorphous, titania nanotube array. The artificial ligament not only provides exceptional osteoinductivity owing to its nanotopography and beneficial ingredients, but also produces periodontium-similar energy dissipation due to the complexity of the force transmission modes and interface sliding. The ligament increases bone-implant contact by more than 18% and simultaneously reduces the effective stress transfer from implant to peri-implant bone by ≈30% as compared to titanium implants, which as far as is known has not previously been achieved. It is anticipated that the concept of an artificial ligament will open new possibilities for developing high-performance implanted materials with increased lifespans.

Polystyrene microplastics induce blood-testis barrier disruption regulated by the MAPK-Nrf2 signaling pathway in rats.

As a persistent pollutant, microplastics (MPs) have been reported to induce sperm quantity decrease in mice. However, the related mechanism remains obscure. Therefore, this study is intended to explore the effects of polystyrene microplastics (PS-MPs) on male reproduction and its related mechanism of blood-testis barrier (BTB) impairment. Thirty-two adult male Wistar rats were divided randomly into four groups fed with PS-MPs for 90 days at doses of 0 mg/day (control group), 0.015 mg/day, 0.15 mg/day, and 1.5 mg/day, respectively. The present results have shown that PS-MP exposure led to the damage of seminiferous tubule, resulted in apoptosis of spermatogenic cells, and decreased the motility and concentration of sperm, while the abnormality of sperm was elevated. Meanwhile, PS-MPs could induce oxidative stress and activate the p38 MAPK pathway and thus deplete the nuclear factor erythroid-2 related factor 2 (Nrf2). Noteworthily, PS-MPs led to the BTB-related protein expression decrease. All these results demonstrated that PS-MP exposure may lead to the destruction of BTB integrity and the apoptosis of spermatogenic cells through the activation of the MAPK-Nrf2 pathway. The current study provided novelty evidence for elucidating the effects of PS-MPs on male reproductive toxicity and its potential mechanism.