Materials with three-dimensional micro- and nanoarchitectures exhibit many beneficial mechanical, energy conversion and optical properties. However, these three-dimensional microarchitectures are significantly limited by their scalability. Efforts have only been successful only in demonstrating overall structure sizes of hundreds of micrometres, or contain size-scale gaps of several orders of magnitude. This results in degraded mechanical properties at the macroscale. Here we demonstrate hierarchical metamaterials with disparate three-dimensional features spanning seven orders of magnitude, from nanometres to centimetres. At the macroscale they achieve high tensile elasticity (>20%) not found in their brittle-like metallic constituents, and a near-constant specific strength. Creation of these materials is enabled by a high-resolution, large-area additive manufacturing technique with scalability not achievable by two-photon polymerization or traditional stereolithography. With overall part sizes approaching tens of centimetres, these unique nanostructured metamaterials might find use in a broad array of applications.

Due to its unique atom-thick 2D structure and remarkable physicochemical properties, graphene has been making a profound impact in many areas of science and technology. In particular, a great deal of recent attention has been attracted to explore graphene and its derivatives for photoelectrochemical applications, with the potential to harness graphene's excellent properties for opening up new opportunities in next generation photoelectrochemical systems. Over the past few years, much work has been done in the design and preparation of novel graphene-based materials for a wide range of applications in photoelectrochemistry, ranging from photoelectrochemical solar cells, photocatalytic decomposition of organic pollutants, photocatalytic splitting of H 2 O, photocatalytic conversion for fuels, and so on. In this review article, we summarize the state of research on graphene-based materials from the standpoint of photoelectrochemistry. The prospects and further developments in this exciting field of graphene-based materials are also discussed. Broader contextDuring the past decades, various semiconductors (such as TiO 2 and ZnO) have been proven to be excellent photocatalysts for photoelectrochemical applications. However, there are still many challenges that need to be resolved, including the enhancement of solar energy conversion, the suppression of the recombination of photogenerated electron-hole pairs, and the effective utilization of visible light. On the basis of graphene's unique structure and excellent properties, the combination of graphene with semiconductors presents the possibility to possess simultaneously excellent adsorptivity, transparency, conductivity and controllability, which could facilitate effective photoelectrochemical performance. Over the past few years, much work has been attempted on the design and preparation of novel graphene-based materials and the exploration of their applications in photoelectrochemistry, and considerable advances in this area have already been made. This review article explores and summarizes the recent advances in graphene-based materials for photoelectrochemical applications, including photoelectrochemical solar cells, photocatalytic decomposition, photocatalytic splitting of H 2 O, photocatalytic conversion for fuels, and so forth. Also, the prospects and further developments of graphene-based materials in this exciting eld are suggested.

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All‐inorganic perovskite CsPbI3 quantum dots (QDs) offer much better stability for photovoltaic applications. Unfortunately, their cell efficiencies are hindered by the low carrier transport efficiency of QD‐assembled films. In addition, agglomeration‐induced phase change of QDs poses another problem for material and device degradation. Herein, the use of µ‐graphene (µGR) to crosslink QDs to form µGR/CsPbI3 film is demonstrated. It is found that the resultant QDs film provides not only an effective channel for carrier transport, as witnessed by much improved conductivity but also significantly better stability against moisture, humidity, and high temperature stresses. The µGR/CsPbI3 based solar cell shows increased device performance. More specifically, compared to the solar cell without the µGR treatment, VOC is improved to 1.18 from 1.16 V, JSC to 13.59 from 13.17 mA cm−2, and FF to 72.6 from 68.1%, and overall power conversion efficiency to as high as 11.40 from 10.41%, a 12% increase. In addition, the instability originating from the thermal/moisture‐induced QD agglomeration is also greatly suppressed by the µGR crosslinking. The optimized device retains >98% of its initial efficiency after being stored in N2 atmosphere for one month. Importantly, under 60% humidity and 100 °C thermal stresses, the µGR/CsPbI3 devices show much better stability.

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Background: Circular RNAs (circRNAs) have recently emerged as a new family of noncoding RNAs that are involved in the causation and progression of various cancers. However, the roles of circRNAs in the tumorigenesis of gastric cancer (GC) are still largely unknown. Methods: The expression profiles of circRNAs in GC were identified in open GEO database and were evaluated at the mRNA level in clinical GC samples compared with paired non-tumorous tissues. Kaplan-Meier survival curve was used to analyze the correlation of circRNA and patients' prognosis. Subsequently, the circular structures of candidate circRNAs were validated by Sanger sequencing, divergent primer PCR, and RNase R treatments. Gain-and loss-of-function analyses were performed to evaluate the functional significance of it in GC initiation and progression. Dual-luciferase reporter and RNA pull-down assays were used to identify the microRNA (miRNA) sponge mechanism of circRNAs.Results: The expression of circRHOBTB3 was lower in GC tissues and cell lines. Downregulation of circRHOBTB3 was significantly correlated with poor differentiation and unfavorable prognosis in patients with GC. Overexpression of circRHOBTB3 in GC cells led to decreased proliferation and induced G 1 /S arrest in vitro, accompanied with inhibited xenograft tumor growth in vivo, while the opposite effects were achieved in circRHOBTB3-silenced cells. Furthermore, we demonstrated that circRHOBTB3 acts as a sponge for miR-654-3p and verified that p21 is a novel target of miR-654-3p.Conclusion: Taken together, this study revealed that circRHOBTB3 might function as competing endogenous RNA (ceRNA) for miR-654-3p, which could contribute to growth inhibition of GC through activating p21 signaling pathway. Our data suggested that circRHOBTB3 would serve as a novel promising diagnosis marker and therapeutic target for GC.

Recently, the biomass "bottom-up" approach for the synthesis of graphene quantum dots (GQDs) has attracted broad interest because of the outstanding features, including low-cost, rapid, and environmentally friendly nature. However, the low crystalline quality of products, substitutional doping with heteroatoms in lattice, and ambiguous reaction mechanism strongly challenge the further development of this technique. Herein, we proposed a facile and effective strategy to prepare controllable sulfur (S) doping in GQDs, occurring in a lattice substitution manner, by hydrothermal treatment of durian with platinum catalyst. S atoms in GQDs are demonstrated to exist in the thiophene structure, resulting in good optical and chemical stabilities, as well as ultrahigh quantum yield. Detailed mechanism of the hydrothermal reaction progress was investigated. High-efficiency reforming cyclization provided by platinum was evidenced by the coexistence of diversified sp-fused heterocyclic compounds and thiophene derivatives. Moreover, we also demonstrated that saccharides in durian with small molecular weight (<1000 Da) is the main carbon source for the forming GQDs. Because of the desulfurizing process, controllable photoluminescence properties could be achieved in the as-prepared GQDs via tuning doping concentrations.

The photoelectrochemical detection method is a newly developed and promising analytical method for biosensing. In this work, photoactive TiO(2) nanotubes (TNs) immobilized with horseradish peroxidase (HRP) were prepared and used for visible-light-activated photoelectrochemical detection of H(2)O(2). TNs were fabricated by anodic oxidation of titanium substrate and possessed large surface areas, good uniformity and conformability, and high porosity, which were favorable for enzyme immobilization. Electrochemical and UV-vis spectroscopic measurements demonstrated that TNs provided excellent matrixes for the adsorption of HRP and the adsorbed HRP effectively retained its bioactivities. The photocurrent spectra of HRP/TNs showed an obvious photocurrent response under visible-light irradiation (lambda > or = 400 nm), suggesting the possibility of photoelectrochemical detection of H(2)O(2) upon visible-light irradiation. It was found that the generated photocurrent of HRP/TNs at 400 nm was significantly enhanced after the addition of H(2)O(2) in solution and the photocurrent intensity increased with the increase of the H(2)O(2) concentration. The HRP/TNs electrode displayed a linear range of 5.0 x 10(-7)-3.5 x 10(-5) M and a low detection limit of 1.8 x 10(-7) M for H(2)O(2) determination. Thus, the protein-immobilized TNs would be expected to be a novel photoactive material for photoelectrochemical biosensing. This proposed strategy may open a new avenue for the applications of nanotubular TiO(2) in visible-light-activated photoelectrochemical biosensing, which could largely reduce the destructive effect of UV light and the photoholes generated by illuminated TiO(2) to biomolecules.