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This work describes a new nanosensor for the simple, rapid, portable, colorimetric analysis of mercury(II) (Hg2+) ions by combining the sensitive Tyndall effect (TE) of colloidal Au nanoparticles (AuNPs) with specific thymine–Hg2+–thymine (T–Hg2+–T) coordination chemistry for the first time. For the TE-inspired assay (TEA), in the presence of Hg2+ in a sample, the analyte can selectively mediate the hybridization of three types of flexible single-stranded DNAs (ssDNAs) to form stable rigid double-stranded DNAs (dsDNAs) via the T–Hg2+–T ligand interaction. Subsequent self-assembly of the dsDNAs with terminal thiol groups on the AuNPs' surfaces led to their “double” aggregation in addition to the lack of sufficient ssDNAs as the stabilizing molecules in a high-salt solution, resulting in a remarkably enhanced TE signal that positively relied on the Hg2+ level. The results demonstrated that such a TEA method enabled rapid naked-eye qualitative analysis of 625 nM Hg2+ within 10 min with an inexpensive laser pointer pen as an inexpensive handheld light source to generate the TE response. Making use of a smartphone for portable TE readout could further quantitatively detect the Hg2+ ions in a linear concentration range from 156 to 2500 nM with a limit of detection as low as 25 nM. Moreover, the developed equipment-free nanosensor was also used to analyze the Hg2+ ions in real samples including tap water, drinking water, and pond water, the obtained recoveries were within the range of 93.68 to 108.71%. To the best of our knowledge, this is the first report of using the AuNPs and functional nucleic acids to design a TE-based biosensor for the analysis of highly toxic heavy metal ions.

A new broad-spectrum responsive organic-inorganic hybrid photocatalyst (PI@BWO) was successfully prepared by in-situ growing Bi2WO6 nanosheets onto the surface of π-π stacking perylene imide. The obtained PI@BWO hybrids with different composition exhibited enhanced photocatalytic activity for Bisphenol A (BPA) degradation. Among them, 30% PI@BWO exhibited optimal photocatalytic degradation efficiency, which is 2.6 and 3.9 times higher than that of pristine PI and BWO, respectively. Furthermore, PI@BWO also performed good stability and recyclability. Remarkably, the π-conjugation of PI facilitated the separation of charge carriers and improved the utilization of sunlight for PI@BWO. The introduction of BWO nanosheets also enhanced the adsorption capacity for contaminants and provided much more plentiful active sites, promoting the next photocatalytic reaction. Most importantly, PI@BWO could produce abundant reactive species (such as 1O2 and ·OH) via the charge carrier transfer and energy transfer dual transfer approach, therefore leading to stronger oxidation ability. The photocatalytic degradation mechanism and pathway of the PI@BWO hybrids were finally proposed. Overall, this present work might provide a new insight into the designing and preparation of efficient organic-inorganic hybrid photocatalysts for environmental-friendly removal of hazardous organic pollutants.

Ti3C2Tx shows potential as an electrode material of supercapacitors due to its unique layered structures for ion diffusion as well as excellent chemical/physical properties. However, the layer stacking and the insufficient conductivity due to the terminated surface groups have limited this application essentially. In the present study, a three-dimensional B3+ ion-intercalated Ti3C2Tx network (B-Ti3C2Tx) was combined with hollow carbon nanospheres (HCNS), which improved the electric transport performance of Ti3C2Tx by reducing the surface functional groups and hindering the restacking of Ti3C2Tx nanosheets effectively. Thus, a new set of 3D hierarchical B-Ti3C2Tx/HCNS composite materials was obtained here with a superior electrochemical performance higher than that of single Ti3C2Tx in the present study, and many other reported Ti3C2Tx-containing materials in literature. In addition, an excellent electrochemical cycling stability with above 91% retention over 3000 cycles was also obtained for this new hybrid material. This work provides a new direction to promote the Ti3C2Tx-based materials for high-performance supercapacitors.

Background and Purpose: Endothelial repair upon vascular injury is critical for the protection of vessel integrity and prevention of the development of vascular disorders, but the underlying mechanisms remain poorly understood. In this study, we investigated the role of zyxin and its associated cyclic adenosine monophosphate (cAMP) signaling in the regulation of re-endothelialization after vascular injury.Experimental Approach: In zyxin-/- and wild-type mice, wire injury of the carotid artery was carried out, followed by Evans blue staining, to evaluate the re-endothelialization. Mice with endothelium-specific zyxin knockout were used to further determine its role. An in vitro wound-healing assay was performed in primary human endothelial cells (ECs) expressing zyxin-specific short-hairpin RNAs (shRNAs) or scrambled controls by measuring cell migration and proliferation. The effects of the cAMP signaling agonist forskolin were assessed.Key Results: The re-endothelialization of the injured carotid artery was impaired in zyxin-deficient mice, whereas the rate of cell proliferation was comparable with that in wild-type controls. Furthermore, endothelium-specific deletion of zyxin led to similar phenotypes. Knockdown of zyxin by shRNAs in primary human ECs significantly reduced cell migration in the wound-healing assay. Notably, forskolin enhanced endothelial migration in a dose-dependent manner, and this was dependent on zyxin through its interaction with vasodilator-stimulated phosphoprotein. In addition, forskolin promoted the re-endothelialization of the injured carotid artery, and this was compromised by zyxin deficiency.Conclusion and Implications: This study reveals zyxin as a new player in endothelial repair, which is promoted by forskolin, after vascular injury. Thus, zyxin-mediated signaling might be a potential treatment target for diseases involving vascular injury.

This work initially reports a new nanosening method for simple, sensitive, specific, visual detection of mercury (II) (Hg2+) and glutathione (GSH) using the Tyndall Effect (TE) of the same colloidal gold nanoparticle (GNP) probes for efficient colorimetric signaling amplification. For the TE-inspired assay (TEA) method, arginine (Arg) molecules are pre-modified on the GNPs' surfaces (Arg-GNPs). Upon the Hg2+ introduction, it can be specifically coordinated with the terminal –NH2 and –COOH groups of the Arg molecules to make the Arg-GNPs aggregate, producing a significantly-enhanced TE signal in the reaction solution after its irradiation by a 635-nm red laser pointer pen. On the other hand, the introduction of the GSH results in the production of the original Arg-GNPs’ weak TE response, as it is able to bind such metal ion via mercury-thiol reactions to inhibit the above aggregation. Under the optimal conditions, the utility of the new TEA method is well demonstrated to quantitatively detect the Hg2+ and GSH with the aid of a smartphone as a portable TE reader during the linear concentration ranges of 50–3000 and 10–3000 nM, respectively. The detection limits for the Hg2+ and GSH are estimated to be as low as ∼3.5 and ∼0.3 nM, respectively. The recovery results obtained from the detection of Hg2+ in the complex tap and pond water samples and the assay of GSH in real human serum and urine samples are also satisfactory.

A highly stable and effective electrochemiluminescence (ECL) sensing system of cadmium sulfide nanowires/reduced graphene oxide (CdS NWS/rGO) hybrid is presented for supersensitive detection of pentachlorophenol (PCP). CdS nanowire is for the first time exploited in ECL sensing. The rGO served as both ECL signal amplifier and immobilization platform, can perfectly enhance the ECL intensity and stability of the sensing system. With S 2 O 8 2− as coreactant, the ECL signal can be significantly quenched by the addition of PCP. The established ECL sensing system presents a wider linear range from 1.0 × 10 −14 to 1.0 × 10 −8 M and a much low detection limit of 2 × 10 −15 M under the optimum test conditions (e.g., pH 7.0 and 100 mM S 2 O 8 2− ). Furthermore, the ECL sensing system displays a good selectivity for PCP detection. The practicability of the ECL sensing system in real water sample shows that this system could be promisingly applied in the analytical detection of PCP in real water environments.

Different concentrations of jasmonic acid (JA) and benzothiadiazole (BTH) were sprayed on 2-year-old Rosa rugosa‘Plena’ seedlings. The induced resistance of JA and BTH to Sphaerotheca pannosa (Wallr.) and the changes of their related physiological indices were investigated. Results showed that JA and BTH treatments had inhibitory impacts on S. pannosa infection. The optimal concentration of JA and BTH was 0.5 mmol/L for the disease-resistance induction of the leaves, its inductive effect was up to 66.36% for BTH and 54.49% for JA. Our results confirmed that exogenous JA and BTH significantly improved R. rugose ‘Plena’ resistance to S. pannosa. When treated with JA and BTH, activities of the three defense enzymes (POD, PPO, and PAL) increased significantly. Contents of total phenolics, flavonoids, and lignin also increased significantly. It is inferred from these results that exogenous JA and BTH could improve the resistance of R. rugose ‘Plena’ to S. pannosa through enhancing activities of the defensive enzymes and accumulation of secondary metabolites in the leaves.

Osteoporosis is a disease in which the density and quality of bone are reduced, causing bones to become weak and so brittle that a fall or even mild stresses can cause a fracture. Current drug treatment consists mainly of antiresorptive agents that are unable to stimulate new bone formation. Our recent studies have defined a critical role of gingiva-derived mesenchymal stem cells (GMSCs) in attenuating autoimmune arthritis through inhibition of osteoclast formation and activities, but it remains to be ruled out whether the administration of GMSCs to patients with osteoporosis could also regulate osteoblasts and eventually affect bone formation and protection. With the use of an ovariectomized mouse model, we here demonstrated that adoptive transfer of GMSCs regulated the balance of osteoclasts and osteoblasts, eventually contributing to dynamic bone formation. Validation by RNA sequencing (RNA-seq), single-cell sequencing, revealed a unique population of CD39+ GMSC that plays an important role in promoting bone formation. We further demonstrated that CD39 produced from GMSC exerted its osteogenic capacity through the Wnt/β-catenin pathway. Our results not only establish a previously unidentified role and mechanism of GMSC for bone promotion but also a potential therapeutic target for management of patients with osteoporosis and other bone loss conditions., Graphical Abstract, Existing osteoporosis treatments mainly consist of antiresorptive agents, which fail to stimulate new bone formation. Zheng and colleagues demonstrated that adoptive transfer of gingiva-derived mesenchymal stem cells regulates the balance of osteoclasts and osteoblasts in osteoporosis, and the immunomodulatory molecule CD39 plays an important role in promoting bone formation.

Although Ti3C2Tx MXene is emerging as a new two-dimensional energy storage material with excellent physical and chemical properties, its surface termination and easy restacking have severely limited such a promising application. Herein, we reported a new modification strategy for Ti3C2Tx by grafting with sulfonic acid group and decoration with N-doped carbon (abbreviated as S–Ti3C2Tx@N–C), after which the interlayer spacing of the wrinkled Ti3C2Tx was effectively expanded with additive active sites, and the electrochemical performance was enhanced apparently. Based on a standard three-electrode system, the specific capacitance of S–Ti3C2Tx@N–C-700 °C (annealed at 700 °C) electrode was elevated to a high value as 260 F g−1 at a current density of 0.8 A g−1, about 3 times that of Ti3C2Tx, also higher than that of many other Ti3C2Tx-based materials in literature. Moreover, the S–Ti3C2Tx@N–C-700 °C electrode maintains 90% of the initial capacitance after 5000 cycles. This work provides a simple and efficient approach of the electrode modification suitable for further energy applications.

A magnetically separable trifunctional nanocatalyst Fe3O4@SiO2–NH2 was synthesized and characterized by TEM, FT-IR, XRD, TGA, and EA. The designed nanocatalyst was found to be highly active for selective synthesis of nitroalkenes with nitromethane and aromatic aldehyde through cooperative trifunctional catalysis of primary amine, secondary amine and Si–OH groups on the surface of the catalyst. Under the optimized conditions, various representative substrates were extended to obtain the corresponding products in moderate or excellent yields. After the reaction, the trifunctional nanocatalyst was easily recovered and recycled by applying an external magnet. In addition, a possible cooperative trifunctional catalysis mechanism was also proposed.

A magnetically separable trifunctional nanocatalyst Fe3O4@SiO2–NH2 was synthesized and characterized by TEM, FT-IR, XRD, TGA, and EA. The designed nanocatalyst was found to be highly active for selective synthesis of nitroalkenes with nitromethane and aromatic aldehyde through cooperative trifunctional catalysis of primary amine, secondary amine and Si–OH groups on the surface of the catalyst. Under the optimized conditions, various representative substrates were extended to obtain the corresponding products in moderate or excellent yields. After the reaction, the trifunctional nanocatalyst was easily recovered and recycled by applying an external magnet. In addition, a possible cooperative trifunctional catalysis mechanism was also proposed.