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To increase the monodispersity of magnetic hybrid nanocomposites, a novel ultrasonic method was introduced to synthesize uniform Fe3O4@SiO2-Ag nanospheres. The immobilized Ag nanocrystals were tunable by varying the experimental conditions. An antibacterial assay indicated that the Fe3O4@SiO2-Ag nanospheres exhibited excellent antibacterial activities against Staphylococcus aureus and Escherichia coli, in which the minimum inhibition concentrations (MIC) were 40 μg mL−1 and 20 μg mL−1, respectively. The live/dead bacterial cell fluorescence stain assay agreed well with the antibacterial assay. The CCK-8 results indicated these nanospheres were bio-compatible for human normal cells and presented relative cytotoxicity against HepG2 tumor cells. These nanospheres could be easily uptaken by the cells and they could affect bacterial cells both inside and outside the cell membrane, which enable them to be promisingly applied in future biomedical areas. [ABSTRACT FROM AUTHOR]

Supramolecular amide hydrogen-bond interactions between bundles of necklace-like chains based on superparamagnetic hollow Fe3O4 nanoparticle beads could be indirectly quantified by shear stress and magnetorheological analyses. First, a facile magnetic field-induced method was developed for the preparation of the superparamagnetic Fe3O4 hierarchical chain structures. Primary Fe3O4 hollow nanospheres, hollow nanosphere-assembled chains, and partially hollow nanosphere-assembled chains were successfully prepared. These superparamagnetic nanoparticles and chains could be well dispersed in aqueous solutions. The magnetic hollow nanoparticle chains possess a strong magnetorheological effect in aqueous solutions. Bundle wire-like structures based on chains or nanospheres could be formed with different magnetic field alignments. The hollow nanostructure greatly strengthens the as-formed bundle wire-like structures such that the chains have a larger magnetorheological effect than that of the hollow nanospheres. It is envisaged that a specific cell transfection mechanism of chains and wires could involve a partial disassembly from bundles to individual chains/wires before endocytosis. The force that is exerted on this disassembly from bundles to individual chains/wires in a specific medium, which are quantified by shear stress and magnetorheological analyses, would shed light on cell magnetofection mechanisms. [ABSTRACT FROM AUTHOR]

A coumarin-based fluorescent chemosensor CAQA has been synthesized. It can selectively and sensitively recognize Cu2+ in aqueous acetonitrile solutions. Using the Cu-containing complex CAQA–Cu2+ as a sensing ensemble, the device demonstrates highly selective recognition of His/biothiols and was applied in fluorescence imaging of histidine in hard-to-transfect living cells. [ABSTRACT FROM AUTHOR]

Bionic robots have great potential in healthcare, rescue, and surveillance. However, most soft actuators can only realize one or two deformation modes, which largely limit the application in complex environments. This study develops electric/Infrared (IR) light/magnetic multi‐field coupling soft actuators by combining liquid crystal elastomers (LCE), liquid metal (LM) and magnetic Ecoflex (Mecoflex). Originated from the synergistic effect of the differed thermal expansion and the liquid crystal phase transition, the actuator can realize outstanding large deformations (bending angle > 300°) at ultra‐low voltages (1.0 V). In addition, by designing the molecular orientation in the LCE layer and programming the magnetization in the Mecoflex layer, the bending or helical bending deformations can be controlled under electric/magnetic and IR light/magnetic coupling actuation. Based on the complex deformation capability, bionic climbing plants and two kinds of quadrupedal robots are developed. With the structural design of the quadrupedal robots, they can flexibly switch deformations to pass through complex environments by controlling the externally applied coupling fields, which demonstrates their broad potential in practical applications. [ABSTRACT FROM AUTHOR]

Several ternary composites that are based on branched polyethyleneimine (bPEI 25 kDa, polydispersity 2.5, 0.1 or 0.2 ng), citrate-coated ultrasmall superparamagnetic iron oxide nanoparticles (citrate-NPs, 8–10 nm, 0.1, 1.0, or 2.5 µg), and reporter circular plasmid DNA pEGFP-C1 or pRL-CMV (pDNA 0.5 µg) were studied for optimization of the best composite for transfection into glioblastoma U87MG or U138MG cells. The efficiency in terms of citrate-NP and plasmid DNA gene delivery with the ternary composites could be altered by tuning the bPEI/citrate-NP ratios in the polymer composites, which were characterized by Prussian blue staining, in vitro magnetic resonance imaging as well as green fluorescence protein and luciferase expression. Among the composites prepared, 0.2 ng bPEI/0.5 μg pDNA/1.0 µg citrate-NP ternary composite possessed the best cellular uptake efficiency. Composite comprising 0.1 ng bPEI/0.5 μg pDNA/0.1 μg citrate-NP gave the optimal efficiency for the cellular uptake of the two plasmid DNAs to the nucleus. The best working bPEI concentration range should not exceed 0.2 ng/well to achieve a relatively low cytotoxicity. [ABSTRACT FROM AUTHOR]

The two‐dimensional (2‐D) Janus and amphiphilic molybdenum disulfide (MoS2) nanosheet with opposite optical activities on each side (amphichiral) is synthesized by modifying sandwich‐like bulk MoS2 with tannic acid and cholesterol through biphasic emulsion method. This new type of amphichiral Janus MoS2 nanosheet consists of a hydrophilic and positive optical activity tannic acid side as well as a hydrophobic and negative optical activity cholesterol side thereby characterized by circular dichroism. Surface‐directed orientational differentiation assemblies are performed for the as‐synthesized 2D material and are characterized by contact angle, infrared spectroscopy, X‐ray photoelectron, and circular dichroism spectroscopies. The amphiphilic nature of the materials is demonstrated by the pre‐organization of the nanosheets on either hydrophobic or hydrophilic surfaces, providing unprecedented properties of circular dichroism signal enhancement and wettability. Selective detachment of the surface organic groups (cholesterol and tannic acid fragments) is realized by matrix‐assisted laser desorption/ionisation ‐ time‐of‐flight (MALDI‐TOF) mass spectrometry, and the dual substrate release in tissue is detected by ex vivo mass spectrometry imaging. [ABSTRACT FROM AUTHOR]

With the prevalence of drug-resistant bacteria and the waning effects of antibiotics, nanoplatform has become an effective strategy for fighting infections. This work reports a dipolar-hollowed α-Fe 2 O 3 @Au/Polydopamine (PDA) nanospindle which possesses both photothermal-photodynamic (PTT-PDT) coupling antibacterial and drug carrying performance. Firstly, the spindle type α-Fe 2 O 3 @Au/PDA particle was prepared by a simple one-step strategy and then the dipolar-hollow structure was obtained by controlling etching the inside α-Fe 2 O 3 core with hydrochloric acid. After further loading the photosensitizer zinc phthalocyanine (ZnPc), the dipolar-hollowed α-Fe 2 O 3 @Au/PDA-ZnPc nanospindles were obtained. Owing to the dipolar-hollowed interior, the nanospindles are also effective in carrying antitumor drug doxorubicin (DOX) and shows a good drug loading-release behavior. The dipolar-hollowed α-Fe 2 O 3 @Au/PDA nanospindles exhibits a high antibacterial performance against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under near-infrared (NIR) and Xenon lamp irradiation. When α-Fe 2 O 3 @Au/PDA-ZnPc nanospindles concentration was increased to 100 μg/mL, the antibacterial rate was close to 100 %. In comparison to the original α-Fe 2 O 3 @Au/PDA nanospindles, the product achieved a lower effective antibacterial temperature. This triple-mode therapy (PTT/PDT/Drug) provides an interesting design idea for anisotropic therapeutic nanoplatform which can be applied in low-temperature antibacterial and drug delivery. • A dipolar-hollowed α-Fe 2 O 3 @Au/PDA nanospindle prepared by a coating-etching strategy • The inner hollow nanostructure of α-Fe 2 O 3 @Au/PDA nanospindles can be controlled. • α-Fe 2 O 3 @Au/PDA-ZnPc nanospindles exhibit PTT-PDT antibacterial activity. • Dipolar-hollowed α-Fe 2 O 3 @Au/PDA nanospindles had a lower antibacterial temperature. [ABSTRACT FROM AUTHOR]

Pathogenic infections pose a major threat to global public health, and what's worse is that the bacteria in infected places often exist in the form of biofilms, making it impossible for antibiotics and other contact bactericidal substances to penetrate their interior. Therefore, looking for an effective method with synergistic antibacterial and biofilm removal properties is a key challenge. A kind of magnetic MXene@Fe 3 O 4 /PDA nanosheets with antibacterial properties of photothermal magnetic coupling are reported in this paper. Fe 3 O 4 was grown in situ on MXene nanosheets and then coated with a layer of polydopamine (PDA). MXene@Fe 3 O 4 /PDA nanosheet (120 μg/mL) showed an over 95% inhibition rate against E. coli and S. aureus under 808 nm laser irradiation. In addition, peroxidase-like activity can produce reactive oxygen species. The photothermal antibacterial properties were further enhanced under the action of rotating magnetic field. The antibacterial activity was increased to close to 99.99%, and the removal effect of biofilm was also very good. The photothermal and magnetic coupled antibacterial effects can reduce the amount of MXene@Fe 3 O 4 /PDA, thus it is expected to reduce the damage caused by overheating normal tissues and is safer than pure photothermal therapy. • The MXene@Fe 3 O 4 /PDA nanosheet has excellent photothermal conversion property. • The nanosheet exhibits magnetically enhanced photothermal antibacterial activity and biofilm removal properties. • The nanosheet concentration required for coupling antibacterial is low. [ABSTRACT FROM AUTHOR]

Flexible sensors have been widely used in smart wearable devices, in which the multifunctional selectivity and mechanical property receive the main attention. However, a simple process for preparing sensors which can recognize different forms of mechanical stimuli is still a challenge. This paper reports a magnetic thin-film sensor (MP-Ag-MP) consisting of magnetic PDMS matrix and conductive Ag nanowires film with pine-branch microstructure by using sandpaper as an abrasive template. Due to its upper and lower asymmetric microstructures, the sensor has diametrically opposed electrical signal responses to bending stimuli in different directions, thus enabling the differentiated monitoring of in-plane and out-plane bending, and the sensitivities can respectively reach −9.04 × 10−2/mm and 12.87 × 10−2/mm in the sensing range. Moreover, it can also respond promptly to different magnetic field directions and intensities, which demonstrates excellent magnetic sensing performance. The sensor can be applied to monitor various human joint motions and construct a Morse code encryption-decryption system. Furthermore, a stress-magnetic bi-functional control system integrated with Bluetooth transmission function can be designed to wirelessly control the motion of the smart cart. As a result, this randomly distributed pine-branch microstructure endows the wonderful bi-directional sensing function and provides high potential application in smart wearable devices. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Precise modulation of immuno-inflammatory response is crucial to control periodontal diseases and related systemic comorbidities. The present nanosystem with the controlled-release and cell-penetrating manner enhances the inflammation modulation effects of baicalein in human gingival epithelial cells (hGECs) for better oral healthcare. We constructed a red-emissive mesoporous silica nanoparticle-based nanosystem with cell-penetrating poly(disulfide) (CPD) capping, through a facile in-situ polymerization approach. It was featured with a glutathione-responsive manner and instant cellular internalization capacity for precisely delivering baicalein intracellularly. Laboratory experiments assessed whether and how the nanosystem per se with the delivered baicalein could modulate immuno-inflammatory responses in hGECs. The in-situ polymerized CPD layer capped the nanoparticles and yet controlled the release of baicalein in a glutathione-responsive manner. The CPD coating could facilitate cellular internalization of the nanosystem via endocytosis and thiol-mediated approaches. Notably, the intracellularly released baicalein effectively downregulated the expression of pro-inflammatory cytokines through inhibiting the NF-κB signaling pathway. The nanosystem per se could modulate immuno-inflammatory responses by passivating the cellular response to interlukin-1β. This study highlights that the as-synthesized nanosystem may serve as a novel multi-functional vehicle to modulate innate host response via targeting the NF-κB pathway for precision healthcare. [ABSTRACT FROM AUTHOR]

Nanoplatforms have been considered as an effective strategy to address the resistance problem of traditional antimicrobial agents. This work reports a magnetic Fe 3 O 4 @AgAu@PDA (Fe 3 O 4 @AgAu@Polydopamine) antibacterial nanomaterial which possesses magnetically induced force-thermal coupling antibacterial effect. The polydopamine shell has good biocompatibility and the AgAu nanorods immobilized on the surface of the magnetic nanospindle not only create a rough surface for the anisotropic nanospindle but also endow it with high photothermal performance and oxidase-like/peroxide-like activities. Besides the original Ag ions release antibacterial activity, Fe 3 O 4 @AgAu@PDA nanospindles (80 μg/mL) also exhibit a good photothermal antibacterial effect (>90%) against Escherichia coli and Staphylococcus aureus under near - infrared (NIR) irradiation. Interestingly, when a rotating magnetic field (RMF) is applied, the antibacterial activity of the magnetic nanospindles can be further increased to nearly 100%. More importantly, in comparison to the Fe 3 O 4 @AgAu@PDA nanospheres, the Fe 3 O 4 @AgAu@PDA nanospindles exhibit a better antibacterial effect. By exploring the interaction between different particles and bacteria under magnetic field conditions, the basic mechanism of force-thermal coupling antibacterial was deeply explored and extended to biofilm removal. The results of cytotoxicity assay show that Fe 3 O 4 @AgAu@PDA nanospindles have good biocompatibility. Thus, the proposed strategy provides broad promise in antimicrobial therapy and biomedicine. [Display omitted] [ABSTRACT FROM AUTHOR]

Pathogenic bacteria and difficult-to-degrade pollutants in water have been serious problems that always plague people. Therefore, finding a "one stone-two birds" method that can quickly catalyze the degradation of pollutants and show effective antibacterial behavior become an urgent requirement. This work reports a facile one-step strategy for fabricating a Rambutan-like Fe 3 O 4 @AgAu@PDA (Fe 3 O 4 @AgAu@Polydopamine) core/shell nanosphere with both catalytic and antibacterial activities which can be critically improved by externally applying an NIR laser irradiation (NIR, 808 nm) and a rotating magnetic field. Typically, the Rambutan-like Fe 3 O 4 @AgAu@PDA nanosphere have a rather rough surface due to the AuAg bimetallic nanorods sandwiched between the Fe 3 O 4 core and the PDA shell. Owing to the penetrated PDA shell, AgAu nanorods show high and magnetically recyclable photothermal-enhanced catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol and they can also be applied to initiate TMB oxidation under the help of NIR heating condition. Moreover, Fe 3 O 4 @AgAu@PDA shows a moderate antibacterial activity due to the weak release of Ag+. Under applying a rotating external magnetic field, the rough-surface Fe 3 O 4 @AgAu@PDA nanospheres produce a controllable magnetolytic force on the bacterial due to their good affinity. As a result, the Fe 3 O 4 @AgAu@PDA nanospheres show a "magnetolytic-photothermal-Ag+" synergistic antibacterial behavior against E. coli and S. aureus. [Display omitted] • A Rambutan-like Fe 3 O 4 @AgAu@PDA (Fe 3 O 4 @AgAu@Polydopamine) core/shell nanosphere is prepared by a one-step strategy. • The nanospheres have NIR enhanced catalytic activity for 4-nitrophenol reduction and TMB oxidation. • The excellent performance of AgAu bimetallic catalysis was investigated. • The nanospheres show an obvious "magnetolytic-photothermal-Ag+" coupling antibacterial performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel magnetic MXene@Fe 3 O 4 /Au/polydopamine (PDA) nanosheet is developed. • MXene provides more uniformly dispersed active sites for Au nanocrystals. • PDA-confined-Au-nanocrystals hybrid shell is achieved by a simple one-step method. • The MXene@Fe 3 O 4 /Au/PDA nanosheet has excellent photothermal conversion property. • The nanosheet exhibits magnetically-enhanced photothermal antibacterial activity. • The edge of the nanosheet cut the cytomembrane similar to a magnetic "hot nanoblade". Harmful bacteria are common substances in water that endanger human health, so it is urgent to establish a simple system that can tackle these hazardous substances simultaneously. In this work, a novel magnetic MXene@Fe 3 O 4 /Au/polydopamine (PDA) nanosheet with excellent photothermal-magnetolytic coupling antibacterial performance is developed. MXene, Au and polydopamine all have good photothermal properties, so the photothermal conversion efficiency of the MXene@Fe 3 O 4 /Au/PDA nanosheet reaches as high as 48.7%. After 6 min of 808 nm laser irradiation, the MXene@Fe 3 O 4 /Au/PDA nanosheets (120 μg·mL−1) can achieve nearly 100% antibacterial effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In comparison to the sole photothermal treatment, the nanosheet at lower concentration (80 μg·mL−1) also exhibit stronger antibacterial properties against both Gram-negative and Gram-positive bacteria during the photothermal-magnetic coupling treatment. The result is mainly because the heat generated by the photothermal effect of the nanosheet is directly transferred to the cell membrane, and the edge of the nanosheet cuts the cytomembrane similar to a magnetic "hot nanoblade", resulting in subsequent shrinkage, deformation and even rupture. [ABSTRACT FROM AUTHOR]

• Reviewing on photocatalytic hydrogen evolution using Ir(III) complex as a photosensitizer. • Illustrating structure-catalytic activity relationship and photo-redox mechanism. • Giving insight into how to design Ir(III) complexes for efficient PHE. Among the vast array of transition metal complexes which have been previously reported, organometallic compounds based on iridium(III) and relevant metal complexes have been shown to possess particularly interesting features; including a wide range of versatile chemical structures, unique photophysical properties and, perhaps most importantly, outstanding photocatalytic capabilities. This review surveys the design and evaluation of these compounds as photocatalysts/photosensitizers in systems for photocatalytic hydrogen evolution (PHE) reactions. Photo-redox mechanisms are addressed, and structure-catalytic activity relationships are identified to guide the future design of more efficient and robust photocatalytic systems. [ABSTRACT FROM AUTHOR]

Local surface plasmon resonance (LSPR) of noble metal nanoparticles plays a significant role in nanocatalysis via directly harvesting optical energy from resonant light. However, the photothermally-assistant catalytic application is limited due to the narrow visible/infrared absorption range and low photothermal conversion efficiency. Herein, a sandwich-structured MXene@Au/Polydopamine (PDA) nanosheet with good hydrophilicity, large specific surface area and tri-photothermal components is developed for nanocatalysis. The Au/PDA hybrid shells are covered on the MXene nanosheets via a simple one-step redox-oxidize polymerization method. As a result, the catalytic dynamic of MXene@Au/PDA nanosheets on reducing 4-nitrophenol reaches to 0.28 min−1·mg−1, which is about 2 times larger than that of the nanocatalysts without NIR light irradiation. Owing to the well protection of PDA shell, after 10 cycles of reduction of 4-nitrophenol, MXene@Au/PDA nanosheets still maintain more than 90% activity. This work in depth insights into NIR light-assistant avenue to enhance the catalytic activity of noble metal nanocatalysts and highlights an easy synthetic model for heterogeneous catalysts based on MXene nanocomposites. An MXene@Au/PDA nanosheet with sandwiched nanostructure has been rationally fabricated by a simple in situ redox-oxidizing polymerization method. Under the irradiation of near-infrared light, the catalytic dynamic of the MXene@Au/PDA nanosheet is excitingly improved by 2 times, thus shows a typical photothermal-enhanced catalytic activity. [Display omitted] [ABSTRACT FROM AUTHOR]

Second-generation type III-B rotaxane dendrons, equipped with succinimide and acetylene functional groups, were synthesized successfully and characterized by NMR spectroscopy and mass spectrometry. A cell viability study of a dendron with a normal cell line of L929 fibroblast cells revealed no obvious cytotoxicity at a range of 5 to 100 μM. The nontoxic properties of the sophisticated rotaxane dendron building blocks provided a choice of bio-compatible macromolecular machines that could be potentially developed into polymeric materials. [ABSTRACT FROM AUTHOR]

The synthesis of mechanically interlocked molecules is valuable due to their unique topologies. With π-stacking intercomponent interaction, e.g., phenanthroline and anthracene, novel [2]rotaxanes have been synthesized by dynamic imine clipping reaction. Their X-ray crystal structures indicate the π-stackings between the anthracene moiety (stopper) on the thread and the (hetero)aromatic rings at the macrocycle of the rotaxanes. Moreover, the length of glycol chains affects the extra π-stacking intercomponent interactions between the phenyl groups and the dimethoxy phenyl groups on the thread. Dynamic combinatorial library has shown at best 84% distribution of anthracene-threaded phenanthroline-based rotaxane, coinciding with the crystallography in that the additional π-stacking intercomponent interactions could increase the thermodynamic stability and selectivity of the rotaxanes. [ABSTRACT FROM AUTHOR]

In this study, we report a new class of rhodamine-based fluorescent sensors for highly selective and sensitive detection of Pd2+ ions in aqueous medium. A rhodamine-based palladium sensor RPS and a coumarin-rhodamine Förster resonance energy transfer (FRET)-pair based palladium sensor FPS were synthesized with the designed podand ligand for Pd2+ ion recognition. They showed both colorimetric change and fluorometric change in the presence of Pd2+ ion due to the opening of their spirolactam rings. Both chemosensors are highly selective to Pd2+ over the other 24 different metal ions and they are selective to palladium species in +2 oxidation state, RPS showed a 70-fold fluorescent turn-on while FPS showed a 1.75-fold ratiometric change at I 599 / I 470. Furthermore, RPS showed low cell cytotoxicity and it was successfully used to image Pd2+ in BEAS-2B lung epithelial cells. © 2019 Elsevier Science. All rights reserved. Image 1 • A new class of rhodamine-based fluorescent sensors for highly selective and sensitive detection of Pd2+ ions in aqueous medium. •Two chemosensors RPS and FPS were synthesized with the designed podand ligand for Pd2+ ion recognition •RPS shows low cell cytotoxicity and it has been successfully used to image Pd2+ in BEAS-2B lung epithelial cells. •Both chemosensors RPS and FPS showed visible color changes and hence they can serve as "naked eye" detection of Pd2+ ion. •RPS and FPS are stable in aqueous solutions and exhibited high selectivity toward palladium in +2 oxidation state. Based on the selectivity and interference studies, both RPS and FPS are selectivetowards Pd2+ ion and hence they are able to differentiate Pd2+ over the other metal ions in the testing samples. [ABSTRACT FROM AUTHOR]

A novel multi-layered AuAg@C@AuAg/PDA core/shell nanosphere with a uniform nanoframe-core and nanocrystals-satellites nanostructure was developed. Owing to the well distributed AuAg nanocrystals and inner AuAg nanoframes protected by PDA, the AuAg@C@AuAg/PDA shows high catalytic activity and the rate constant (K) to catalyst weight ratio reaches as high as 3.63 min−1 mg-1. • AuAg@C@AuAg/PDA core/shell nanosphere with a hollow interior is prepared by a facile method. • AuAg@C@AuAg/PDA shows a unique nanostructure with an inner AuAg nanoframe core and external AuAg-nanocrystals satellites. • This method can be applied in preparing AuAg@C@AuAg/PDA core/shell particles with different morphologies. • AuAg@C@AuAg/PDA shows excellent performance in catalyzing the reduction of 4-nitrophenol. This work reported a facile method for fabricating multi-layered polydopamine (PDA) encapsulated AuAg@C@AuAg core/shell nanosphere with a hollow interior. During the synthetic process, the preliminary Ag@C nanosphere is easily covered by an AuAg/PDA hybrid layer through the in situ redox-oxidized polymerization to form the Ag-AuAg@C@AuAg/PDA precursor, in which the AuAg bimetallic nanocrystals are simultaneously obtained via the electrochemical substitution reaction. After etching the residue Ag core, the final AuAg@C@AuAg/PDA hybrid nanosphere is achieved and the inner AuAg shows a unique nanoframe-like nanostructure. The carbon shell plays an important role for the formation and structure evolution of the AuAg@C@AuAg/PDA, and the composition can be modulated by varying the polymerization process. Owing to the well distributed AuAg nanocrystals and inner AuAg nanoframes, the AuAg@C@AuAg/PDA shows better performance than Ag-AuAg@C@AuAg/PDA precursor in catalyzing 4-nitrophenol, and the rate constant (K) to catalyst weight ratio reaches as high as 3.63 min−1 •mg-1. As a result, this work not only offers a hybrid bi-metallic nanocatalyst with excellent performance, but also has valuable implications for compositional modulation of hollow interior multi-layered nanostructure in adsorption, drug delivery, and nanocatalysis. [ABSTRACT FROM AUTHOR]

Although bimetallic noble nanostructures often possess high activity in nanocatalysis, their controllable fabrication, tunable catalytic activity, and easy separation remain significant challenges. In this study, an Fe 3 O 4 @AgPd/Polydopamine (Fe 3 O 4 @AgPd/PDA) nanosnowman loaded with an AgPd nanocage was designed by a one-step template-disposition-redox polymerization method. The AgPd nanocage endowed the product with high catalytic activity for the reduction of organic pollutants (4-NP, MO, MB). Interestingly, under near-infrared (NIR) light, the catalytic kinetics of the Fe 3 O 4 @AgPd/PDA nanosnowman on catalytic reduction of organic pollutants increased by 2.6, 1.57, and 5.45 times, respectively. The asymmetric nanostructure facilitated the separation of electron-hole pairs, promoted electron transfer, and accelerated the catalytic activity. Density functional theory (DFT) analysis indicated that the electron transfer between the AgPd alloy and the Fe 3 O 4 nanosphere played a critical role on the high catalytic activity. Moreover, Fe 3 O 4 @AgPd/PDA also demonstrated excellent catalytic activity in the Heck carbon-carbon coupling reaction with a >95% conversion rate and >99% selectivity. Owing to the well-encapsulated PDA shell and outstanding magnetic properties, the Fe 3 O 4 @AgPd/PDA nanosnowman exhibited good cyclic catalytic activity. With its multi-mode catalysis, NIR-enhanced catalytic activity, and easy separation, the Fe 3 O 4 @AgPd/PDA nanosnowman exhibits great application potential in nanocatalysis.

Warmth preservation in cold climates requires a long-term heat supply. Conventional thermal devices usually deliver excessive heat and have difficulty preventing heat loss. Herein, to achieve durable thermal comfort, an asymmetric composite (AAAC) is devised through vacuum-filtrating silver nanowires (AgNWs) onto the surface of a poly(ethylene glycol) (PEG)-infiltrated aramid nanofiber aerogel. AgNW e-skin can transfer strong Joule heat to the back side of the AAAC, where the infused PEG further stores thermal energy by phase transition and then releases it to the body constantly after the power is off. Base on the Janus structure, the AAAC can provide thermotherapy for human waists and knees, holding a suitable temperature range of 37-39 °C for 5-8 min without a heat source. In addition, low infrared emissivity (0.064-0.315) of e-skin allows the AAAC to conceal thermal targets while producing Joule heat, which achieves comfortable and safe thermal management in multiple occasions including daily life and military warfare.