Super-Assembled Multilayered Mesoporous TiO2 Nanorockets for Light-Powered Space-Confined Microfluidic Catalysis.

In the field of sustainable chemistry, it is still a significant challenge to realize efficient light-powered space-confined catalysis and propulsion due to the limited solar absorption efficiency and the low mass and heat transfer efficiency. Here, novel semiconductor TiO2 nanorockets with asymmetric, hollow, mesoporous, and double-layer structures are successfully constructed through a facile interfacial superassembly strategy. The high concentration of defects and unique topological features improve light scattering and reduce the distance for charge migration and directed charge separation, resulting in enhanced light harvesting in the confined nanospace and resulting in enhanced catalysis and self-propulsion. The movement velocity of double-layered nanorockets can reach up to 10.5 µm s-1 under visible light, which is approximately 57 and 119% higher than that of asymmetric single-layered TiO2 and isotropic hollow TiO2 nanospheres, respectively. In addition, the double-layered nanorockets improve the degradation rate of the common pollutant methylene blue under sustainable visible light with a 247% rise of first-order rate constant compared to isotropic hollow TiO2 nanospheres. Furthermore, FEA simulations reveal and confirm the double-layered confined-space enhanced catalysis and self-propulsion mechanism.

Effect of Hesperetin on Isoprenaline-induced Hypertrophy of H9C2 Cardiomyocytes.

An experiment was carried out to investigate the effect of hesperetin on isoproterenol-induced H9C2 cardiomyocyte hypertrophy and its possible mechanism. For this aim, H9C2 cardiomyocytes were coincubated with different concentrations of hesperetin (0.125, 0.25, 0.5, 1µmol/L) and isoproterenol to detect the changes in the area of H9C2 cells, the expression of cardiac hypertrophy marker ß-MHC mRNA and autophagy marker LC3II; H9C2 cells were coincubated with hesperetin and isoproterenol at the optimal intervention concentration, and the intervention time was set to 6h, 12h, 24h, respectively, and the changes of H9C2 cell area, ß-MHC mRNA and LC3II expression were detected. Results showed that hesperetin could reduce isoproterenol-induced H9C2 cardiomyocyte area enlargement; hesperetin can reduce ß-MHC mRNA expression in isoproterenol-induced H9C2 cardiomyocyte; hesperetin can increase the expression level of LC3II in isoproterenol-induced H9C2 cardiomyocyte. Conclusion Hesperetin may improve the hypertrophy of H9C2 cardiomyocytes induced by isoproterenol by activating autophagy.

Superassembled Hierarchical Asymmetric Magnetic Mesoporous Nanorobots Driven by Smart Confined Catalytic Degradation.

Invited for the cover of this issue is the group of Biao Kong at Fudan University. The image depicts a hierarchical asymmetric magnetic mesoporous hollow nanorobot that combines the functionalities of magnetic responsiveness, reusability, sustainable motility and durable motion, showing excellent pollutant degradation capability. Read the full text of the article at. 10.1002/chem.202200307.

Superassembled Hierarchical Asymmetric Magnetic Mesoporous Nanorobots Driven by Smart Confined Catalytic Degradation.

Micro/nanoscale robotics has received great attention in many important fields. However, it is still a great challenge to construct nanorobots simultaneously possessing multifunctionality, well-controlled directionality, and fast and durable motion as well as fully compatible and biodegradable components. Here, a hierarchical, asymmetric, hollow, catalytic, magnetic, and mesoporous nanorobot has been fabricated through a multistep interfacial superassembly strategy. The multilayer composites consist of hollow silica nanoflasks sequentially coated with a highly magnetic responsive Fe3 O4 layer, a mesoporous silica layer with homogeneous vertical channels, and a layer of catalytic gold nanoparticles on both the inner and outer surfaces. Furthermore, para-nitrophenol was used as a model pollutant to trigger self-motility of the nanoflasks by confined catalytic degradation (CCD). We found that the bottleneck morphology and mesoporous surface both improved the catalytic nanoparticle loading capability and CCD effect, thus enabling efficient self-motility and a durable movement capacity of ∼100 h. In addition, the catalytic performance was improved by 180 % compared with that of solid spherical nanoparticles.

General Synergistic Capture-Bonding Superassembly of Atomically Dispersed Catalysts on Micropore-Vacancy Frameworks.

Atomically dispersed catalysts are a new type of material in the field of catalysis science, yet their large-scale synthesis under mild conditions remains challenging. Here, a general synergistic capture-bonding superassembly strategy to obtain atomically dispersed Pt (Ru, Au, Pd, Ir, and Rh)-based catalysts on micropore-vacancy frameworks at a mild temperature of 60 °C is reported. The precise capture via narrow pores and the stable bonding of vacancies not only simplify the synthesis process of atomically dispersed catalysts but also realize their large-scale preparation at mild temperature. The prepared atomically dispersed Pt-based catalyst possesses a promising electrocatalytic activity for hydrogen evolution, showing an activity (at overpotential of 50 mV) about 21.4 and 20.8 times higher than that of commercial Pt/C catalyst in 1.0 M KOH and 0.5 M H2SO4, respectively. Besides, the extremely long operational stability of more than 100 h provides more potential for its practical application.

Interfacial Superassembly of Light-Responsive Mechanism-Switchable Nanomotors with Tunable Mobility and Directionality.

Mechanism-switchable nanomotors are expected to exhibit high adaptability and wide applicability. Herein, for the first time, we report a flask-shaped carbon@Pt@fatty-acid nanomotor with a light-induced switch between nonionic self-diffusiophoresis and bubble propulsion. This nanomotor is fabricated through superassembly of platinum nanoparticles on the surface of carbon nanobottles, and fatty acids are infused into the cavity of carbon nanobottles to serve as a light-sensitive switch. Such a nanomotor can be propelled via catalytic decomposition of H2O2 by platinum nanoparticles, exhibiting self-diffusiophoresis with opening-forward migration. Upon 980 nm laser irradiation, the fatty acids melt due to the photothermal effect and are released from the cavity, switching the dominant operational mechanism to bubble propulsion with bottom-forward migration. Compared with self-diffusiophoresis, bubble propulsion shows higher mobility and better directionality due to the hindered self-rotation. Simulation results further reveal that the confinement effect of the cavity, which facilitates the nucleation of nanobubbles, leads to the switch to bubble propulsion. This study offers an insight into the relationship between nanostructures, fundamental nanomotor operational mechanisms, and apparent propulsion performance, as well as provides a novel strategy for the regulation of movement, which is instructive for both the design and applications of nanomotors.

Kinetics-Controlled Super-Assembly of Asymmetric Porous and Hollow Carbon Nanoparticles as Light-Sensitive Smart Nanovehicles.

The rational design and controllable synthesis of hollow nanoparticles with both a mesoporous shell and an asymmetric architecture are crucially desired yet still significant challenges. In this work, a kinetics-controlled interfacial super-assembly strategy is developed, which is capable of preparing asymmetric porous and hollow carbon (APHC) nanoparticles through the precise regulation of polymerization and assembly rates of two kinds of precursors. In this method, Janus resin and silica hybrid (RSH) nanoparticles are first fabricated through the kinetics-controlled competitive nucleation and assembly of two precursors. Specifically, silica nanoparticles are initially formed, and the resin nanoparticles are subsequently formed on one side of the silica nanoparticles, followed by the co-assembly of silica and resin on the other side of the silica nanoparticles. The APHC nanoparticles are finally obtained via high-temperature carbonization of RSH nanoparticles and elimination of silica. The erratic asymmetrical, hierarchical porous and hollow structure and excellent photothermal performance under 980 nm near-infrared (NIR) light endow the APHC nanoparticles with the ability to serve as fuel-free nanomotors with NIR-light-driven propulsion. Upon illumination by NIR light, the photothermal effect of the APHC shell causes both self-thermophoresis and jet driving forces, which propel the APHC nanomotor. Furthermore, with the assistance of phase change materials, such APHC nanoparticles can be employed as smart vehicles that can achieve on-demand release of drugs with a 980 nm NIR laser. As a proof of concept, we apply this APHC-based therapeutic system in cancer treatment, which shows improved anticancer performance due to the synergy of photothermal therapy and chemotherapy. In brief, this kinetics-controlled approach may put forward new insight into the design and synthesis of functional materials with unique structures, properties, and applications by adjusting the assembly rates of multiple precursors in a reaction system.

Interfacial Super-Assembly of Ordered Mesoporous Carbon-Silica/AAO Hybrid Membrane with Enhanced Permselectivity for Temperature- and pH-Sensitive Smart Ion Transport.

Nanofluidic devices have been widely used for diode-like ion transport and salinity gradients energy conversion. Emerging reverse electrodialysis (RED) nanofluidic systems based on nanochannel membrane display great superiority in salinity gradient energy harvesting. However, the imbalance between permeability and selectivity limits their practical application. Here, a new mesoporous carbon-silica/anodized aluminum (MCS/AAO) nanofluidic device with enhanced permselectivity for temperature- and pH-regulated energy generation was obtained by interfacial super-assembly method. A maximum power density of 5.04 W m-2 is achieved, and a higher performance can be obtained by regulating temperature and pH. Theoretical calculations are further implemented to reveal the mechanism for ion rectification, ion selectivity and energy conversion. Results show that the MCS/AAO hybrid membrane has great superiority in diode-like ion transport, temperature- and pH-regulated salinity gradient energy conversion.

Ligand-Mediated Spatially Controllable Superassembly of Asymmetric Hollow Nanotadpoles with Fine-Tunable Cavity as Smart H2O2-Sensitive Nanoswimmers.

Ligand-mediated interface control has been broadly applied as a powerful tool in constructing sophisticated nanocomposites. However, the resultant morphologies are usually limited to solid structures. Now, a facile spatially controllable ligand-mediated superassembly strategy is explored to construct monodispersed, asymmetric, hollow, open Au-silica (SiO2) nanotadpoles (AHOASTs). By manipulating the spatial density of ligands, the degree of diffusion of silica can be precisely modulated; thus the diameters of the cavity can be continuously tuned. Due to their highly anisotropic, hollow, open morphologies, we construct a multicompartment nanocontainer with enzymes held and isolated inside the cavity. Furthermore, the resulting enzyme-AHOASTs are used as biocompatible smart H2O2-sensitive nanoswimmers and demonstrate a higher diffusion coefficient than other nanoscaled swimmers. We believe that this strategy is critical not only in designing sophisticated hollow nanosystem but also in providing great opportunities for applications in nanomaterial assembly, catalysis, sensors, and nanoreactors.

Sequential Superassembly of Nanofiber Arrays to Carbonaceous Ordered Mesoporous Nanowires and Their Heterostructure Membranes for Osmotic Energy Conversion.

The capture of sustainable energy from a salinity gradient, in particular, using renewable biomass-derived functional materials, has attracted significant attention. In order to convert osmotic energy to electricity, many membrane materials with nanofluidic channels have been developed. However, the high cost, complex preparation process, and low output power density still restrict the practical application of traditional membranes. Herein, we report the synthesis of highly flexible and mechanically robust nanofiber-arrays-based carbonaceous ordered mesoporous nanowires (CMWs) through a simple and straightforward soft-templating hydrothermal carbonization approach. This sequential superassembly strategy shows a high yield and great versatility in controlling the dimensions of CMWs with the aspect ratio changes from about 3 to 39. Furthermore, these CMWs can be used as novel building blocks to construct functional hybrid membranes on macroporous alumina. This nanofluidic membrane with asymmetric geometry and charge polarity exhibits low resistance and high-performance energy conversion. This work opens a solution-based route for the one-pot preparation of CMWs and functional heterostructure membranes for various applications.

Interfacial Super-Assembly of T-Mode Janus Porous Heterochannels from Layered Graphene and Aluminum Oxide Array for Smart Oriented Ion Transportation.

Salinity gradient energy existing in seawater and river water is a sustainable and environmentally energy resource that has drawn significant attention of researchers in the background of energy crisis. Nanochannel membrane with a unique nano-confinement effect has been widely applied to harvest the salinity gradient energy. Here, Janus porous heterochannels constructed from 2D graphene oxide modified with polyamide (PA-GO) and oxide array (anodic aluminum oxide, AAO) are prepared through an interfacial super-assembly method, which can achieve oriented ion transportation. Compared with traditional nanochannels, the PA-GO/AAO heterochannels with asymmetric charge distribution and T-mode geometrical nanochannel structure shows directional ionic rectification features and outstanding cation selectivity. The resulting heterochannel membrane can achieve a high-power density of up to 3.73 W m-2 between artificial seawater and river water. Furthermore, high energy conversion efficiency of 30.3% even in high salinity gradient can be obtained. These achievable results indicate that the PA-GO/AAO heterochannels has significant potential application in salinity gradient energy harvesting.

Interfacial Super-Assembly of Ordered Mesoporous Silica-Alumina Heterostructure Membranes with pH-Sensitive Properties for Osmotic Energy Harvesting.

Osmotic energy existing between seawater and freshwater is a potential blue energy source that can mitigate the energy crisis and environmental pollution problems. Nanofluidic devices are widely utilized to capture this blue energy owing to their unique ionic transport properties in the nanometer scale. However, with respect to nanofluidic membrane devices, high membrane inner resistance and a low power density induced by disordered pores and thick coating as well as difficulty in manufacturing still impede their real-world applications. Here, we demonstrate an interfacial super-assembly strategy that is capable of fabricating ordered mesoporous silica/macroporous alumina (MS/AAO) framework-based nanofluidic heterostructure membranes with a thin and ordered mesoporous silica layer. The presence of a mesoporous silica layer with abundant silanol and a high specific surface area endows the heterostructure membrane with a low membrane inner resistance of about 7 KΩ, excellent ion selectivity, and osmotic energy conversion ability. The power density can reach up to 4.50 W/m2 by mixing artificial seawater and river water through the membrane, which is 20 times higher than that of the conventional 2D nanofluidic membrane, and outperforms about 30% compared to other 3D porous membranes. More intriguingly, the interesting pH-sensitive osmotic energy conversion property of the MS/AAO membrane is subsequently recognized, which can realize a higher power density even in acidic or alkaline wastewater, expanding the application range, especially in practical applications. This work presents a valuable paradigm for the use of mesoporous materials in nanofluidic devices and provides a way for large-scale production of nanofluidic devices.

Interfacial Super-Assembly of Nanofluidic Heterochannels from Layered Graphene and Alumina Oxide Arrays for Label-Free Histamine-Specific Detection.

Nanofluidic devices with well-defined channels have shown great potential for biosensing, separation and, energy conversion. Recently, two-dimensional (2D) materials have been widely used for constructing novel nanofluidic devices owing to their high specific surface, abundant surface charge, and low cost. However, 2D-based nanofluidic devices for highly sensitive biosensing have drawn little attention. Herein, we developed a 2D material-based nanofluidic heterochannel with an asymmetric T-mode nanochannel structure and surface charge polarization distribution. This heterochannel was composed of layered graphene oxide modified with Nα, Nα-bis(carboxymethyl)-l-lysine (containing metal-nitrilotriacetic chelates, NTA) and an oxide array (NTA-GO/AAO), which can achieve remarkable selectivity, specificity, and label-free detection of the neurotransmitter histamine based on a metal ion displacement mechanism. A detection limit of 1 nM can be obtained using the NTA-GO/AAO heterochannel. This study provides a simple and label-free platform for developing a 2D-based nanofluidic heterochannel for specific molecular detection.

Concentrated solar light for rapid crystallization of nanomaterials and extreme enhancement of photoelectrochemical performance.

In this communication, a concentrated solar light (CSL) annealing strategy is proposed with a Fresnel lens as the concentrator for rapid and effective crystallization of nanomaterials. More interestingly, the CSL can be integrated into photoelectrochemical devices and achieved an unprecedented photocurrent density.

Sputtering gold nanoparticles on nanoporous bismuth vanadate for sensitive and selective photoelectrochemical aptasensing of thrombin.

In this communication, we report the first demonstration of an efficient photoelectrochemical aptasensor based on sputtering Au nanoparticle-modified nanoporous BiVO4 for the excellent sensitive and selective detection of thrombin with a low detection limit of 0.5 pM and a large linear range.