Lipoic acid-mediated oral drug delivery system utilizing changes on cell surface thiol expression for the treatment of diabetes and inflammatory diseases.

Lipoic acid (LA), which has good safety and oral absorption, is obtained from various plant-based food sources and needs to be supplemented through human diet. Moreover, substances with a disulfide structure can enter cells through dynamic covalent disulfide exchange with thiol groups on the cell membrane surface. Based on these factors, we constructed LA-modified nanoparticles (LA NPs). Our results showed that LA NPs can be internalized into intestinal epithelial cells through surface thiols, followed by intracellular transcytosis via the endoplasmic reticulum-Golgi pathway. Further mechanistic studies indicated that disulfide bonds within the structure of LA play a critical role in this transport process. In a type I diabetes rat model, the oral administration of insulin-loaded LA NPs exhibited a more potent hypoglycemic effect, with a pharmacokinetic bioavailability of 5.42 ± 0.53%, representing a 1.6 fold enhancement compared to unmodified PEG NPs. Furthermore, a significant upregulation of surface thiols in inflammatory macrophages was reported. Thus, we turned our direction to investigate the uptake behavior of inflammatory macrophages with increased surface thiols towards LA NPs. Inflammatory macrophages showed a 2.6 fold increased uptake of LA NPs compared to non-inflammatory macrophages. Surprisingly, we also discovered that the antioxidant resveratrol facilitates the uptake of LA NPs in a concentration-dependent manner. This is mainly attributed to an increase in glutathione, which is involved in thiol uptake. Consequently, we employed LA NPs loaded with resveratrol for the treatment of colitis and observed a significant alleviation of colitis symptoms. These results suggest that leveraging the variations of thiol expression levels on cell surfaces under both healthy and diseased states through an oral drug delivery system mediated by the small-molecule nutrient LA can be employed for the treatment of diabetes and certain inflammatory diseases.

A semiconducting hybrid of RhOx/GaN@InGaN for simultaneous activation of methane and water toward syngas by photocatalysis.

Prior to the eventual arrival of carbon neutrality, solar-driven syngas production from methane steam reforming presents a promising approach to produce transportation fuels and chemicals. Simultaneous activation of the two reactants, i.e. methane and water, with notable geometric and polar discrepancy is at the crux of this important subject yet greatly challenging. This work explores an exceptional semiconducting hybrid of RhOx/GaN@InGaN nanowires for overcoming this critical challenge to achieve efficient syngas generation from methane steam reforming by photocatalysis. By coordinating density functional theoretical calculations and microscopic characterizations, with in situ spectroscopic measurements, it is found that the multifunctional RhOx/GaN interface is effective for simultaneously activating both CH4 and H2O by stretching the C-H and O-H bonds because of its unique Lewis acid/base attribute. With the aid of energetic charge carriers, the stretched C-H and O-H bonds of reactants are favorably cleaved, resulting in the key intermediates, i.e. *CH3, *OH, and *H, to sit on Rh sites, Rh sites, and N sites, respectively. Syngas is subsequently produced via energetically favored pathway without additional energy inputs except for light. As a result, a benchmarking syngas formation rate of 8.1 mol·gcat-1·h-1 is achieved with varied H2/CO ratios from 2.4 to 0.8 under concentrated light illumination of 6.3 W·cm-2, enabling the achievement of a superior turnover number of 10,493 mol syngas per mol Rh species over 300 min of long-term operation. This work presents a promising strategy for green syngas production from methane steam reforming by utilizing unlimited solar energy.

Fe2 O3 /FePO4 /FeOOH Ternary Stepped Energy Band Heterojunction Photoanode with Cascade-Driven Charge Transfer and Enhanced Photoelectrochemical Performance.

Controlling the charge transfer pathway in semiconductors is an important method to improve charge separation efficiency and enhance photoelectrochemical activity. In this work, a Fe2 O3 /FePO4 /FeOOH nanorod photoanode with stepped energy band structure is prepared by a hydrothermal and water bath method. The charge separation efficiency of the ternary heterojunction is higher than that of the traditional type II heterojunction, which might be due to the efficient cascade charge transfer and separation effect of the ternary stepped energy band heterojunction. The H2 and O2 evolution rates for photoelectrochemical water splitting of Fe2 O3 /FePO4 /FeOOH photoanode are 0.247 and 0.111 µmol min-1 , which is 2.15 and 1.95 times that of the Fe2 O3 /FePO4 photoanode, respectively. The incident photocurrent efficiency (IPCE) of Fe2 O3 /FePO4 /FeOOH photoanode under 365 nm light irradiation is 1.5 and 1.8 times that of Fe2 O3 /FePO4 and Fe2 O3 /FeOOH photoanodes, respectively. This work provides an attractive strategy for solar energy conversion to construct efficient photoelectrochemical photoanode materials.

Self-Assembly Mechanism of Complex Corrugated Particles.

A variety of inorganic nanoscale materials produce microscale particles with highly corrugated geometries, but the mechanism of their formation remains unknown. Here we found that uniformly sized CdS-based hedgehog particles (HPs) self-assemble from polydisperse nanoparticles (NPs) with diameters of 1.0-4.0 nm. The typical diameters of HPs and spikes are 1770 ± 180 and 28 ± 3 nm, respectively. Depending on the temperature, solvent, and reaction times, the NPs self-assemble into nanorods, nanorod aggregates, low-corrugation particles, and other HP-related particles with complexity indexes ranging from 0 to 23.7. We show that "hedgehog", other geometries, and topologies of highly corrugated particles originate from the thermodynamic preference of polydisperse NPs to attach to the growing nanoscale cluster when electrostatic repulsion competes with van der Waals attraction. Theoretical models and simulations of the self-assembly accounting for the competition of attractive and repulsive interactions in electrolytes accurately describe particle morphology, growth stages, and the spectrum of observed products. When kinetic parameters are included in the models, the formation of corrugated particles with surfaces decorated by nanosheets, known as flower-like particles, were theoretically predicted and experimentally observed. The generality of the proposed mechanism was demonstrated for the formation of mixed HPs via a combination of CdS and Co3O4 NPs. With unusually high dispersion stability of HPs in unfavorable solvents including liquid CO2, mechanistic insights into HP formation are essential for their structural adaptation for applications from energy storage, catalysis, water treatment, and others.

Fe2O3 nanorods/CuO nanoparticles p-n heterojunction photoanode: Effective charge separation and enhanced photoelectrochemical properties.

Fe2O3/CuO p-n heterojunction photoelectrode films were fabricated by growing CuO nanoparticles on Fe2O3 nanorods via an impregnation method. The content of CuO in Fe2O3/CuO films was changed to study the role of CuO on the p-n heterojunction. The obtained Fe2O3/CuO photoelectrodes exhibited high intensity of visible-light absorption and excellence photoelectrochemical (PEC) performance. The incident photocurrent efficiency (IPCE) of Fe2O3/CuO photoanode reached 11.4% under 365 nm light irradiation, which is 2.6 times higher than that of bare Fe2O3 photoanode. In a PEC water splitting reaction, the H2 and O2 production rates for Fe2O3/CuO-3 were 0.294 and 0.130 µmol/min. The enhanced PEC performance was mainly contributed by the enhanced charge separation and the synergism achieved in Fe2O3/CuO p-n heterojunctions. This work could provide a new route to construct efficient Fe2O3-based composite photoelectrodes for the PEC.

Interfacial charge modulation: carbon quantum dot implanted carbon nitride double-deck nanoframes for robust visible-light photocatalytic tetracycline degradation.

Steering charge kinetics at the interface is essential to improve the photocatalytic performance of two-dimensional (2D) material-based heterostructures. Herein, we developed a novel strategy-simultaneously building two kinds of heterojunctions- to modulate interfacial charge kinetics in polymeric carbon nitride (CN) for improving the photocatalytic activity. Using a simple one-step thermal condensation of carbon quantum dot (CQD)-contained supramolecular precursors formed in water, the controllable CQD embedded CN nanoframes possessed two kinds of heterogeneous interfaces within seamlessly stitched micro-area two-dimensional in-plane and out-of-plane domains. These two kinds of heterojunctions can effectively enhance its intrinsic driving force to accelerate the separation and transfer of charge along different directions. Furthermore, the hollow double-deck porous CN-CQD nanoframes with a high surface area (296.74 m2 g-1) endowed more exposed active sites. The remarkable visible-light photocatalytic activity of hollow porous CN-CQD nanoframes was demonstrated by degrading tetracycline (TC) and rhodamine (RhB) as the models, whose robust degradation rate constant is approximately 11 and 29 times higher than that of pristine CN, respectively. This work provides a novel strategy for the interfacial design of the heterophase junction with atomic precision.

Hierarchical Self-assembly of Well-Defined Louver-Like P-Doped Carbon Nitride Nanowire Arrays with Highly Efficient Hydrogen Evolution.

Self-assembled nanostructure arrays integrating the advantages of the intrinsic characters of nanostructure as well as the array stability are appealing in advanced materials. However, the precise bottom-up synthesis of nanostructure arrays without templates or substrates is quite challenging because of the general occurrence of homogeneous nucleation and the difficult manipulation of noncovalent interactions. Herein, we first report the precisely manipulated synthesis of well-defined louver-like P-doped carbon nitride nanowire arrays (L-PCN) via a supramolecular self-assembly method by regulating the noncovalent interactions through hydrogen bond. With this strategy, CN nanowires align in the outer frame with the separation and spatial location achieving ultrastability and outstanding photoelectricity properties. Significantly, this self-assembly L-PCN exhibits a superior visible light-driven hydrogen evolution activity of 1872.9 µmol h-1 g-1, rendering a ~ 25.6-fold enhancement compared to bulk CN, and high photostability. Moreover, an apparent quantum efficiency of 6.93% is achieved for hydrogen evolution at 420 ± 15 nm. The experimental results and first-principles calculations demonstrate that the remarkable enhancement of photocatalytic activity of L-PCN can be attributed to the synergetic effect of structural topology and dopant. These findings suggest that we are able to design particular hierarchical nanostructures with desirable performance using hydrogen-bond engineering.

Strategy to boost catalytic activity of polymeric carbon nitride: synergistic effect of controllable in situ surface engineering and morphology.

Polymeric carbon nitride (CN) is a promising metal-free catalyst plagued by a low intrinsic activity. Herein, a novel strategy based on controllable in situ surface engineering and morphology was developed to synergistically boost the catalytic activity of CN by tuning the hydroxyl groups on its surface and constructing a unique nanostructure. The controllable introduction of hydroxyl groups on CN nanoshells, prepared by the thermal condensation of oxygen-containing supramolecular precursors formed in water, led to spatial separation of the HOMO and LUMO, and effective exciton dissociation, as verified by experiments and ab initio calculations. Furthermore, the hollow hemispherical nanoshell endowed more exposed active sites, optimal mass transport, and dynamic modulations. The optimized hollow hemispherical CN nanoshells exhibited remarkable catalytic activity, with a photoelectrocatalytic OER overpotential of about 330 mV at a current density of 10 mA cm-2, outperforming state-of-the-art precious-metal catalyst IrO2. High activity for the visible-light photocatalytic HER and pollutant degradation were also observed. This study proposes that, through rational surface group modification, a polymer material with high catalytic activity can be practically realized, which is promising for the design of efficient metal-free catalysts.

Doping-Induced Hydrogen-Bond Engineering in Polymeric Carbon Nitride To Significantly Boost the Photocatalytic H2 Evolution Performance.

Unlike graphene, graphitic carbon nitride (CN) polymer contains a weak hydrogen bond and van der Waals (vdWs) interactions besides a strong covalent bond, which controls its final morphology and functionality. Herein, we propose a novel strategy, hydrogen-bond engineering, to tune hydrogen bonds in polymeric CN through nonmetal codoping. Incorporation of B and P dopants breaks partial hydrogen bonds within the layers and simultaneously weakens the vdWs interaction between neighboring layers, resulting in ultrathin codoped CN nanosheets. The two-dimensional structure of the ultrathin sheet, broken hydrogen bonds, and incorporated dopants endow them with efficient visible light harvesting, improved charge separation, and increased active edge sites that synergistically enhance the photocatalytic activity of doped CN. Specifically, the B/P-codoped CN exhibits an extremely high hydrogen-evolution rate of 10877.40 µmol h-1 g-1, much higher than most reported values of CN. This work demonstrates that hydrogen bond engineering is an effective strategy to modify the structure and properties of polymers for various applications.

Synthesis of Emulsion-Templated Magnetic Porous Hydrogel Beads and Their Application for Catalyst of Fenton Reaction.

The pristine Fe3O4 nanoparticle (FeNP) is supposed to be a good catalyst of Fenton processes which have shown significant potential for water purification. Herein the magnetic macroporous hydrogel beads, having an open-cell structure, were synthesized by sedimentation polymerization of pristine FeNP stabilized oil-in-water high internal phase emulsions. The effects of the FeNP amount, internal phase fraction, and the costabilizer Tween85 concentration on the structure, such as interconnecting degree, void size, and its distribution of both the surface and inner of the beads, were investigated. With a methyl orange (MO) aqueous solution passing through a chromatography column that was filled with the FeNPs loaded hydrogel beads, the efficiency of these hydrogel beads as catalyst for Fenton reaction to decompose MO in water was tested. The MO was decomposed quickly at the first hour, followed by decomposed gradually in a further 5 h, and the decomposition rate of MO could be up to 99.6% at the end of the test. Moreover, MO decomposition rate remained over 98.2% in six batches which were run in the same beads filled column. The results showed that these FeNPs loaded porous hydrogel beads were reusable and highly efficient supporter for catalysis of Fenton reaction for decomposing organic pollutants in water.

Macroporous polymers prepared via frozen UV polymerization of the emulsion-templates stabilized by a low amount of surfactant.

Macroporous polymers based on high internal phase emulsions (HIPEs) possess tunable porous structures and device shapes, and these characteristics make it possible for it to be applied in many fields. However, such materials also demonstrate undesirable properties, such as their brittleness and chalkiness, due to a great amount of surfactant required (5.0-50.0%, relative to the external phase) to realize the transformation from HIPEs to macroporous polymers (polyHIPEs). Herein, O/W HIPEs stabilized by a small amount (as low as 0.1 wt%, relative to the external phase) of commercial surfactant were prepared by magnetic stirring and subsequently homogenizing, and well-defined polyHIPEs were obtained through frozen UV polymerization of these HIPEs. In this process, the prepared HIPE was squeezed out by an injector and frozen at once, which effectively prevented the coalescence of internal phase. Then a 365 nm UV light was utilized to initiate the polymerization and the temperature was kept at -20 °C in order to avoid the melting of the frozen HIPE. After the polymerization, samples, having a typical polyHIPE structure, were obtained. Besides, the original monomer, surfactant and the oil (internal phase) were respectively replaced, and well-defined polyHIPEs could still be obtained. All the results suggested that frozen UV polymerization of HIPEs was an effective and universal approach to produce polyHIPEs with a low amount of surfactant.

A ratiometric fluorescent probe for hypochlorous acid determination: Excitation and the dual-emission wavelengths at NIR region.

An interesting ratiometric fluorescent probe with unique optical performance was reported in this work. By modifying on the bridge-head of heptamethine cyanine chromophore with an N-phenyl-N'-ethylene amine thiourea substituent as a chemodosimetric recognition unit, the probe exhibited ratiometric fluorescent response towards hypochlorous acid (HClO). Upon addition of HClO, the absorbance spectra showed a great red shift as large as 150nm from 650nm to 800nm. Employing the isosbestic absorption point at 730nm as an excitation wavelength, a ratiometric fluorescent sensing mode with two long emission wavelengths at 760nm and 820nm was acquired, and thus the probe displayed significant behavior with both the excitation wavelength and the dual-emission wavelengths located at NIR (650-900nm) region exclusively. Also, the probe showed excellent performance in high sensitivity and good selectivity towards HClO over other reactive oxygen species and a wide variety of coexist species in biological pH condition and had been successfully used to detect hypochlorous acid in serum samples and tap water samples.

Neutral nickel(II) phthalocyanine as a stable catalyst for visible-light-driven hydrogen evolution from water.

Neutral nickel(ii) phthalocyanine was found to be an efficient and stable catalyst for photocatalytic H2 evolution from water when coupled with an iridium complex as the photosensitizer and triethanolamine as the sacrificial electron donor. The result shows that the Ni-N sigma bond can enhance the stability of the catalyst.

The microfluidic synthesis of composite hollow microfibers for K+-responsive controlled release based on a host-guest system.

A novel type of composite hollow microfiber with K+-responsive controlled-release characteristics based on a host-guest system is prepared by embedding K+-responsive poly(N-isopropylacrylamide-co-acryloylamidobenzo-15-crown-5) (P(NIPAM-co-AAB15C5)) microspheres in the wall of poly(lactic-co-glycolic acid) (PLGA) microfibers as "micro-valves" using a controllable microfluidic approach. By adjusting the volume change of microspheres in response to the environmental K+ concentration, the release rate of the encapsulated drug molecules from the composite hollow microfibers can be flexibly regulated owing to the change in the interspace size between the microfiber wall and microspheres. When the environmental K+ concentration is increased, due to the formation of stable 2 : 1 "sandwich-type" host-guest complexes of 15-crown-5 units and K+ ions, P(NIPAM-co-AAB15C5) microspheres change from a swollen state to a shrunken state. Thus, the interspace size becomes larger, resulting in a rapid increase in the release rate of encapsulated drugs. When the ambient K+ concentration is decreased, the interspace size becomes smaller due to isothermal swelling of microspheres caused by the decreased amount of host-guest complexes, resulting in a decrease in the release rate. The K+-responsive drug release behaviors are reversible. This kind of K+-responsive hollow microfiber with K+-concentration-dependent controlled-release properties provides a new mode in the design of more rational drug delivery systems, which are highly attractive for biomedical applications.

A Noble-Metal-Free Nickel(II) Polypyridyl Catalyst for Visible-Light-Driven Hydrogen Production from Water.

The complex [Ni(bpy)3](2+) (bpy=2,2'-bipyridine) is an active catalyst for visible-light-driven H2 production from water when employed with [Ir(dfppy)2 (Hdcbpy)] [dfppy=2-(3,4-difluorophenyl)pyridine, Hdcbpy=4-carboxy-2,2'-bipyridine-4'-carboxylate] as the photosensitizer and triethanolamine as the sacrificial electron donor. The highest turnover number of 520 with respect to the nickel(II) catalyst is obtained in a 8:2 acetonitrile/water solution at pH 9. The H2 -evolution system is more stable after the addition of an extra free bpy ligand, owing to faster catalyst regeneration. The photocatalytic results demonstrate that the nickel(II) polypyridyl catalyst can act as a more effective catalyst than the commonly utilized [Co(bpy)3 ](2+). This study may offer a new paradigm for constructing simple and noble-metal-free catalysts for photocatalytic hydrogen production.

A heptamethine cyanine-based colorimetric and ratiometric fluorescent chemosensor for the selective detection of Ag+ in an aqueous medium.

A highly selective and sensitive ratiometric fluorescent chemosensor for Ag(+) in aqueous solution was developed, in a linear range of 0.6 × 10(-7) to 50 × 10(-7) mol L(-1), based on a A-Ag(+)-A binding mode with a heptamethine cyanine motif containing one adenine moiety.

Diethyl 2-{4-diethyl-amino-2-[(dimethyl-carbamothio-yl)-oxy]benzyl-idene}malonate.

In the title compound, C(21)H(30)N(2)O(5)S, the plane of the dimeth-yl-thio-carbamic group makes a dihedral angle of 78.41 (7)° with the central benzene ring. One of the carbonyl groups in the α,ß-unsaturated malonate side chain makes a dihedral angle of 8.73 (10)° with the central benzene ring, while the other carbonyl group makes a dihedral angle of 81.52 (8)°.

Core-shell microspherical Ti(1-x)Zr(x)O2 solid solution photocatalysts directly from ultrasonic spray pyrolysis.

A series of Ti(1-x)Zr(x)O(2) solid solutions photocatalysts (x = 0.000, 0.045, 0.090, 0.135, and 0.180) was directly obtained by an ultrasonic spray pyrolysis method. Compared with previous methods for solid solutions, our preparation was very fast. The resulting samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, nitrogen adsorption, and UV-vis diffuse reflectance spectroscopy. The characterizations revealed core-shell spherical structures of the resulting solid solutions. We evaluated photocatalytic activities of the solid solutions on degradation of rhodamine B in aqueous solution under simulated solar light. It was found that Ti(0.91)Zr(0.09)O(2) solid solution exhibited the highest photocatalytic activity among all the as-prepared samples. Its activity was much higher than that of P25. The formation mechanism of core-shell spherical structures was proposed. Moreover, we successfully extended this method to prepare microspheres of ceria and ceria-zirconia solid solutions. We think this general method may be easily scaled up for industrial production of microspherical solid solutions photocatalysts and catalysts.

A novel ZnII-sensitive fluorescent chemosensor assembled within aminopropyl-functionalized mesoporous SBA-15.

A novel Zn2+-sensitive fluorescent chemosensor SC/SBA-15 has been obtained by the self-assembly of 4-chloroaniline-N-salicylidene (SC), a Schiff base ligand, within the channel of silylation-modified SBA-15 without destroying its hexagonally ordered mesoporous structure. The remarkable 200-fold fluorescence enhancement with a large Stokes shift of 180 nm in luminescence emission upon the addition of Zn2+ is attributed to the formation of a coordinate complex of a large rigid conjugate system and Zn2+ ions.