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A O2N˙-triggered addition 7-endo cyclization to nitro-benzo[b]azepines is reported with good chemo- and regioselectivity. Large-scale operation and handy N-Ts and N-Cbz deprotection reveal the utility of this methodology.

A simple and facile strategy to construct o-nitroaryl urea employing carbodiimides and ceric ammonium nitrate (CAN) has been developed. This protocol achieves the installation of two functional groups in one step with high functional group compatibility. Control experiments show that the reaction mechanism involves an intriguingly concerted nitration/ureation process enabled by CAN, and is distinctive from conventional electrophilic nitrification. The oxygen atom of urea probably originates from the nitrate ions provided by CAN. The late-stage derivatization and gram-scale synthesis reveal the promising utility of this methodology.

The outbreak of infant milk powder poisoning in China attracted worldwide attention. The investigations found that the real culprit of this incident was melamine (Mel), which induced the formation of kidney stones. However, little is known about the formation mechanism of infant stones, not to mention the preventive and therapeutic drugs. Here, through thermodynamic and kinetic tests, simulation in vitro and animal experiments, and multidisciplinary analysis and verification, we found that the formation of this kidney stone is a rate-controlled nano-scale supramolecular layered assembly process: Mel, uric acid (UA) and a small amount of H2O combine through hydrogen bonds to form a planar network supramolecular structure; the planar structures self-assemble layer-by-layer to form ellipsoidal nanocrystals through π–π stacking interactions, van der Waals force, hydrophilic/hydrophobic interaction, etc.; the small nanocrystals gradually grow and aggregate concentrically to form ellipsoidal Mel–UA stones under the control of the matrix. Based on the above process, we screen out an effective inhibitor and eliminator for stones, potassium citrate (K3Cit), which works through both hydrogen bonding and alkalinity. This work solves the most challenging conundrum left by the Mel incident and blazes a trail for the prevention and treatment of kidney stone disease.

CoS2 nanoparticles embedded in Al2O3 nanosheets (CoS2 NP/Al2O3 NSs) have been designed and fabricated using a controllable hydrothermal process followed by a simple low-temperature sulfurization step. The as-prepared CoS2 NP/Al2O3 NSs display combined properties of high nanoporosity, thin thickness and good structural stability. When used as an electrocatalyst for the hydrogen evolution reaction (HER), the composite demonstrates high catalytic activity, including a small overpotential of ∼53 mV, a small Tafel slope of 50.9 mV dec−1 and remarkable stability. Moreover, the CoS2 NP/Al2O3 NSs have a promising lithium-storage capability with high specific capacity (∼1150 mA h g−1 at 100 mA g−1 in the first cycle) and enhanced cycling stability (coulombic efficiency of around 96% for 150 cycles). The facile strategy used to synthesize the unique architecture could be expanded to the preparation of other transition metal sulfides for the HER and lithium ion batteries (LIBs).

Carbon dots (CDs) hold great promise as a class of fluorophores for bioimaging. Here, we report a simple solvothermal approach to prepare photoluminescent CDs derived from the antineoplastic drug etoposide. The CDs show photoluminescence ranging from 365 to 650 nm when excited at 360 nm. When excited at 405, 488 and 543 nm, strong blue, green and red fluorescence can be detected. Our experiments reveal that the CDs can penetrate into the cells in a short time and remain emissive, even at low temperature. Also, optical signals can be detected from mice after hypodermic or intravenous injection. We demonstrated that the CDs can serve as a low-cytotoxicity biological imaging agent for bioimaging in vitro and in vivo.

This communication describes a new strategy to fabricate a nanogel layer around magnetic nanoparticles by surface free-radical polymerization triggered by the cascade reaction of urate oxidase and horseradish peroxidase, which showed high loading capacity, pH-responsive drug release and low cytotoxicity.

Although inhaled steroids are the first choice to control asthma, frequent corticosteroid administration is associated with many side effects such as adrenocortical suppression, Cushing's syndrome and osteoporosis. The purpose of this study was to develop a drug delivery system to overcome the limitation of corticosteroid administration and improve the therapeutic efficacy in an ovalbumin (OVA)-induced allergic asthma rat model. The intercalation of dexamethasone sodium phosphate (Dexa) into layered double hydroxides (LDHs) was achieved by the co-precipitation method and the obtained nanoparticles (Dexa–LDHs) have an average diameter of approximately 100 nm. The X-ray diffraction patterns and FT-IR spectra of the Dexa–LDHs indicated that the Dexa molecules were successfully intercalated into the LDHs via electrostatic interactions. 13C NMR chemical shifts were analysed to clarify the characteristic changes in functional groups after intercalation. Elemental C/H/N and inductively coupled plasma (ICP) analysis revealed the compositions of the nanohybrids. The thermal stability of Dexa anions was enhanced by holding together within the LDHs layers. The drug loading was estimated to be 50.8% and a gradual and biphasic in vitro release behavior of the drugs from LDHs in pH = 7.4 phosphate buffered saline (PBS) was observed. The parabolic diffusion model was used to simulate the release kinetics of Dexa from the LDHs. The potential of Dexa–LDHs as an anti-asthmatic agent was evaluated in the allergic asthma rat model. The results showed that Dexa–LDHs were more effective than Dexa to reduce the number of inflammatory cells in bronchoalveolar lavage (BAL) fluid. Furthermore, Dexa–LDHs significantly inhibited the increase of T-helper-2-type cytokines such as IL-4 and IL-13, and more effectively suppressed airway hyperresponsiveness. In conclusion, these results suggest that Dexa–LDHs could enhance the anti-asthmatic effect of Dexa in the treatment of allergic asthma rats. Our work indicated that LDHs could be a promising candidate for the exploration of new Dexa formulations.

By fluorescence enhancement of a proximity-dependent DNA-scaffolded silver nanocluster probe pair and exonuclease III-mediated signal amplification, we present a new fluorescence turn-on mode and its application for specific DNA detection.

Three-dimensional (3D) flower-like hausmannite architectures of Mn3O4 with uniform morphology have been successfully synthesized by a novel chemical reaction route using cetyltrimethylammonium bromide as the template. Micro/nanostructures of the as-synthesized 3D flower-like Mn3O4 architectures were investigated in detail by a series of analytical techniques. The geometrical shape of 3D flower-like Mn3O4 architectures is structurally perfect, and they are produced with diameters in the range of several hundred nanometers to a few micrometers. Experimental results indicate that two-dimensional nanosheets associated with one-dimensional single-crystalline nanorods self-assembled into three-dimensional flower-like Mn3O4 architectures. The single-crystalline Mn3O4 nanorods are a few hundred nanometers long and several tens of nanometers wide. Different dimensional systems, such as two-dimensional nanosheets, one-dimensional nanorods, and three-dimensional nanoflowers, could provide different building blocks to constitute nanostructured materials. These specific building blocks, which constituted the complex hierarchical architectures with nanostructural features, may offer exciting opportunities for both fundamental research and technological applications.

A smart magnetic targeting drug carrier (MCNC/PAA) comprising an approximately 100 nm sized magnetic colloid nanocrystal cluster (MCNC) core and a pH-responsive cross-linked poly(acrylic acid) (PAA) shell is reported. The abundant carboxyl groups in the shell enable the resultant MCNC/PAA to easily load a large amount of doxorubicin (DOX) (up to 44.6%) via the strong interaction between the DOX and the carboxyl group in a neutral solution. Interestingly, a synergistic pH-responsive effect derived from the entrapped DOX and PAA network was found to effectively manipulate the drug releasing behavior at 37 °C. It was found that the premature release was highly restricted at a pH of 7.4, and upon reduction in pH from 7.4 to 5.0 or 4.0, a large amount of drug was rapidly released. Compared with the synthesized MCNC/PNIPAM, MCNC/PHEMA and MCNC/PDMAPMA nanocarriers, the MCNC/PAA was preferably suited to drug delivery. In addition, the composite nanocarriers could be tracked by magnetic resonance imaging (MRI). The cytotoxicity assay of MCNC/PAA to normal cells indicated that the composite nanospheres were biocompatible and suitable as drug carriers. Meanwhile, the DOX-loaded composite nanospheres had more potent cytotoxicity than free DOX to HeLa cells. These results clearly imply that the MCNC/PAA nanocarrier is a promising platform that can be applied to construct a smart drug delivery system with magnetic targeting and pH-stimulation, as well as tracking by MRI.