Mathematics and art converge in the fractal forms that also abound in nature. We used molecular self-assembly to create a synthetic, nanometer-scale, Sierpinski hexagonal gasket. This nondendritic, perfectly self-similar fractal macromolecule is composed of bis-terpyridine building blocks that are bound together by coordination to 36 Ru and 6 Fe ions to form a nearly planar array of increasingly larger hexagons around a hollow center.

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Photoelectrochemical water splitting based on nanostructured bismuth vanadate (BiVO 4 ) can be a promising strategy to produce low-cost and green H 2 to replace fossil fuels and realize carbon neutrality. Herein, a simple chemical way to realize in situ carbon doping into BiVO 4 crystalline structure is designed and obtained carbon-doped BiVO 4 , namely C-BiVO 4 , can improve the electronic conductivity of BiVO 4 . In addition, the introduction of the synthesized carbon quantum dots (CQDs) as a co-catalyst, immobilizes CQDs onto the C-BiVO 4 nanosheet and acquires the optimized C-BiVO 4 /CQDs heterogeneous structure, which not only boosts light absorption, but also enhances the separation and transfer of the photo-generated charges. Stemming from the dual carbon actions, the as-prepared C-BiVO 4 /CQDs photoanode exhibits an excellent photocurrent density of 4.83 mA cm −2 at 1.23 V versus the RHE without the use of any hole scavengers. To assure the practical application of the sensitive photocatalyst, a polyaniline layer is electroplated onto the C-BiVO 4 /CQDs catalyst as a conducting, electroactive, and protective layer to sustain a remarkable long-term photocurrent density of 2.75 mA cm −2 for 9 hours. This work suggests that the proposed low-cost, environmentally friendly dual carbon actions can modify photocatalyst and achieve green production of H 2 .

The availability of robust, versatile and efficient photocatalysts has been a main bottleneck in practical applications of photocatalytic degradation of organic pollutants. Herein, N-WO 3 /Ce 2 S 3 nanotube bundles (NBs) were synthesized and successfully immobilized on a carbon textile, resulting in a flexible and conducting photocatalyst. Due to the large interfacial area between N-WO 3 and Ce 2 S 3 , the interwoven 3D carbon architecture and, more importantly, the establishment of a heterojunction between N-WO 3 and Ce 2 S 3 , the resultant photocatalyst exhibits excellent light absorption capacity and superior ability to separate photoinduced electron-hole pairs for the photocatalytic degradation of organic compounds in air and water media. Theoretical calculations confirm that the strong electronic interaction between N-WO 3 and Ce 2 S 3 could be beneficial to the enhancement of the charge carrier transfer dynamics of the as-prepared photocatalyst. This work provides a new protocol for constructing efficient flexible photocatalysts for application in environmental remediation.

Rationale: Extracellular vesicles (EVs) have emerged as novel mediators of cell-to-cell communication that are capable of the stable transfer of therapeutic microRNAs (miRNAs), and thus, EVs hold immense promise as a miRNA delivery system for cancer therapy. Additionally, as miRNA-containing EVs are secreted into circulation, miRNAs contained within plasma EVs may represent ideal biomarkers for diseases. The objective of this study was to characterize a potential tumor suppressor miRNA, miR-101, and explore the potential of miR-101 delivery via EVs for in vivo therapy of metastatic osteosarcoma as well as the potential value of plasma EV-packaged miR-101 (EV-miR-101) level for predicting osteosarcoma metastasis.Methods: The relationship of miR-101 expression and osteosarcoma progression was investigated in osteosarcoma specimens by in situ hybridization (ISH), and the potential inhibitory effect of miR-101 was further investigated using in vivo models. Using prediction software analysis, the mechanism of action of miR-101 in osteosarcoma was explored using quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting and dual-luciferase assay. Adipose tissue-derived mesenchymal stromal cells (AD-MSCs) were transduced with lentiviral particles to obtain miR-101-enriched EVs. A Transwell assay and lung metastasis models of osteosarcoma were used to observe the effect of miR-101-enriched EVs on osteosarcoma invasiveness and metastasis. Detection of plasma EV-miR-101 levels was carried out in osteosarcoma patients and healthy controls by qRT-PCR.Results: miR-101 expression was markedly lower in metastatic osteosarcoma specimens compared to non-metastatic specimens. Significantly fewer metastatic lung nodules were formed by Saos-2 cells overexpressing miR-101 and SOSP-9607 cells overexpressing miR-101 injected into mice. With increased miR-101 expression, B cell lymphoma 6 (BCL6) mRNA and protein expression levels were reduced, and miR-101 was found to exert its effects by directly targeting BCL6. AD-MSCs were successfully engineered to secrete miR-101-enriched EVs. Once taken up by osteosarcoma cells, these EVs showed suppressive effects on cell invasion and migration in vitro, and systemic administration of these EVs effectively suppressed metastasis in vivo with no significant side effects. Finally, the EV-miR-101 level was lower in osteosarcoma patients than in healthy controls and even lower in osteosarcoma patients with metastasis than in those without metastasis.Conclusion: Our data support the function of miR-101 as a tumor suppressor in osteosarcoma via downregulation of BCL6. AD-MSC derived miR-101-enriched EVs represent a potential innovative therapy for metastatic osteosarcoma. EV-miR-101 also represents a promising circulating biomarker of osteosarcoma metastasis.