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In this study, a series of hindered urea bond (HUB) containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot procedure. The prepolymers were characterized fully by various techniques. Then, their thermosets were fabricated via UV curing in presence of a photo initiator, and their mechanical property and thermal behavior were investigated and compared. Different from the none HUB containing thermoset, the HUB containing thermosets (defined as PUT) could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical property. Furthermore, zinc oxide (ZnO) nanoparticles were modified with 3-(trimethoxysilyl) propyl methacrylate and the modified ZnO (defined as ZnO-TPM) was dispersed and polymerized into PUT matrix to prepare their nanocomposites. The influence of ZnO-TPM on the mechanical performance of the composites was evaluated, which indicated that the Young's modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt% and then decreased. The composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT sample. In addition, the composite materials exhibited strong UV absorption capacity, implying their potential application in the circumstance where UV-shielding was required. [ABSTRACT FROM AUTHOR]

Recently, as a new breakthrough for lithium-ion storage anode materials, transition metal vanadates, such as Fe 2 VO 4 , have attracted much attention, which, however, still suffer from slow electrochemical kinetics and substantial volume expansion. Hybrid with high conductivity materials is an effective route to deal with these issues. Herein, in situ synthesis of Fe 2 VO 4 @Ti 3 C 2 T x composites with porous sandwich structure by co-precipitation-calcination process was reported. Ultrafine Fe 2 VO 4 nanoparticles (10–15 nm) in situ grew and was anchored on Ti 3 C 2 T x nanosheets, which effectively inhibits both the grain growth for Fe 2 VO 4 and stacking for Ti 3 C 2 T x , thus facilitating the electrochemical kinetics and alleviating the volume change of Fe 2 VO 4 to maintain the integrated structure during the cycling process. As a result, Fe 2 VO 4 @Ti 3 C 2 T x anode shows high Li+ diffusion coefficient (2.72 × 10−11 cm2 s−1) and pseudocapacitive charge storage mechanism (capacitive charge storage contribution 70.85–84.80 % at 0.2–1.0 mV s−1), which guarantee rapid charging and discharging capability. Consequently, outstanding rate performance (1012–595 mAh g−1 at 0.2–3.0 A g−1) and superior cycling capability (663 and 416 mAh g−1 at 1.0 A g−1 for 200 cycles and 2.0 A g−1 for 500 cycles, with the average capacity attrition rate of 0.059 % and 0.053 %, respectively), were achieved, which render Fe 2 VO 4 @Ti 3 C 2 T x composites important potential for lithium-ion storage. • 10–15 nm Fe 2 VO 4 nanoparticles in situ grew and anchored on Ti 3 C 2 T x nanosheets, with a high surface area of 80.32 m2 g–1. • Grain growth of Fe 2 VO 4 nanoparticles and stacking of Ti 3 C 2 T x nanosheets were inhibited by the synergy effect. • Unique structure optimized the electrochemical kinetics and the volume change of Fe 2 VO 4 during cycling process. • High Li+ diffusion (2.72 × 10–11 cm2 s–1) and pseudocapacitive mechanism led to a rapid cycling capability. • Superior Li ion storage (416 mAh g–1 at 2 A g–1 for 500 cycles, 0.053 % average capacity decay) was achieved. [ABSTRACT FROM AUTHOR]

Based on a sandwich structure consisting of nano-Si immune probes and a SiC@Ag SERS-active immune substrate, a kind of ultra-sensitive immunoassay protocol is presented to detect tumor markers in human serum. The nano-Si immune probes were prepared by immobilizing the detecting antibodies onto the surfaces of SiO2-coated Si nanoparticles (NPs) which were modified with 3-(aminopropyl)trimethoxysilane, and the SiC@Ag SERS-active immune substrates were prepared by immobilizing the captured antibodies on Ag film sputtered on SiC sandpaper. To the best of our knowledge, it is the first time that Si NPs are directly used as Raman tags in an immunoassay strategy. And, the SiC@Ag SERS-active substrates exhibit excellent surface enhanced Raman scattering (SERS) performances with an enhancement factor of ∼105, owing to the plasmonic effect of the Ag film on the rough surface of the SiC sandpaper. In our experiments, the sandwich immunoassay structure has been successfully applied to detect prostate specific antigen (PSA), α-fetoprotein (AFP) and carbohydrate antigen 19-9 (CA19-9) in a human serum sample and the limit of detections are as low as 1.79 fg mL−1, 0.46 fg mL−1 and 1.3 × 10−3 U mL−1, respectively. It reveals that the proposed immunoassay protocol has demonstrated a high sensitivity for tumor markers in human serum and a potential practicability in biosensing and clinical diagnostics. [ABSTRACT FROM AUTHOR]

Controlled pesticide release in response to environmental stimuli by encapsulating pesticides in a carrier is a feasible approach to improve the effective utilization rate. In this study, pH-responsive release nanoparticles loaded with penconazole (PE) were prepared by ionic cross-linking of chitosan and carboxymethyl chitosan (PE@CS/CMCS-NPs). PE@CS/CMCS-NPs exhibited good washout resistance and wettability properties, increasing the washing resistance of the pesticide by approximately 20 times under continuous washing. The results of the release experiments showed that nanoparticles had adjustable controlled-release characteristics with the change in pH based on the swelling of nanoparticles. The results of spore germination experiments showed that PE@CS/CMCS-NPs enhanced the inhibitory effect under acidic conditions. The field experiment results showed that PE@CS/CMCS-NPs had a better control effect than PE-aqueous solution, extended the duration and slowed down the dissipation of PE. These results indicated that the CS/CMCS-NPs pH-responsive release system has great potential in the development of an effective pesticide formulation. • A pH-responsive nanoparticles loaded penconazole (PE@CS/CMCS) was constructed. • Combined with the fitting equation of pH swelling and release, the drug release mechanism of PE@CS/CMCS was revealed. • The control efficacy of PE@CS/CMCS against plumeria rust was correlated with pH. • PE@CS/CMCS exhibited good washout resistance and wettability properties. • PE@CS/CMCS had better control effect than PE-aqueous solution, extended the duration and slowed down the dissipation of PE. [ABSTRACT FROM AUTHOR]

Perovskite ZnZrO3 nanoparticles were synthesized by hydrothermal method, and their microstructures and optical properties were characterized. The crystallinity, phase formation, morphology and composition of the as-synthesized nanoparticles were characterized by X-ray diffraction ( XRD), selected area electron diffraction ( SAED), high-resolutiontransmission electron microscopy ( HRTEM), and energy-dispersive X-ray ( EDX) spectroscopy analysis, respectively. TEM images demonstrated that the average particle size of the ZnZrO3 powders was increased with increasing the Zn/ Zr molar ratios in the precursors, and more large ZnZrO3 particles with cubic morphology were observed at high Zn/ Zr molar ratios. In addition, the phase structures of the ZnZrO3 particles were also evolved from a cubic to tetragonal perovskite phase, as revealed by XRD and SAED patterns. HRTEM images demonstrate that surface structures of the ZnZrO3 powders synthesized at high Zn/ Zr molar ratios, are composed of corners bound by the {100} mini-facets, and the surface steps lying on the {100} planes are frequently observed, whereas the (101) facet isoccasionally observed. The formation of such a rough surface structure is understood from the periodic bond chain theory. Quantitative EDX analyses demonstrated that the atomic concentrations (at.%) of Zn: Zr: O in the particles were 20.70:21.07:58.23, as close to the composition of ZnZrO3. In the optical spectra, a significant red shift of the absorption edges (for the ZnZrO3 nanopowders) from UV to visible region (from 394 to 417 nm) was observed as increasing the Zn/ Zr molar ratios in the precursors, which corresponds to that the band gap energies of the ZnZrO3 nanopowders can be continuously tuned from 3.15 to 2.97 eV. This opens an easy way to tune the band gap energies of the ZnZrO3 nanopowders. [ABSTRACT FROM AUTHOR]

Abstract: Silane-modified Fe3O4 nanoparticles can stabilize emulsions of both polar and non-polar oils, and the rheological behavior of these emulsions has been investigated as a function of oil volume fraction (ϕ o), oil polarity and magnetic field intensity (ψ). All the emulsions show a similar elastic response with a modulus plateau at low frequency and a small phase angle (<15°) in dynamic oscillatory shear, and shear-thinning behavior in steady shear measurements. This is independent of ϕ o, oil polarity and ψ. The dynamic modulus (G′) and complex viscosity (η*) increase with an increase in ϕ o and oil polarity, due to enhanced droplet packing and flocculation and particle aggregation on droplet surfaces. The presence of a magnetic field promotes particle attractions and associations and enhances the strength of the three-dimensional particle and droplet networks, thus remarkably increasing G′ and η* and raising the yield stress. The increase in modulus, viscosity and yield stress are beneficial for the elevation of the stability of these functional emulsions. [Copyright &y& Elsevier]

Abstract: Unmodified Fe3O4 nanoparticles do not stabilize Pickering emulsions of a polar oil like butyl butyrate. In order to obtain stable emulsions, the Fe3O4 nanoparticles were modified by either carboxylic acid (RCOOH) or silane coupling agents (RSi(OC2H5)3) to increase their hydrophobicity. The influence of such surface modification on the stability of the resultant Pickering emulsions was investigated in detail for both a non-polar oil (dodecane) and butyl butyrate in mixtures with water. The stability of dodecane-in-water emulsions in the presence of carboxylic acid-coated particles decreases as the length of the alkyl group (R) and the coating extent increase. However, such particles are incapable of stabilizing butyl butyrate-water emulsions even when the carboxylic acid length is decreased to two. However, the silane-coated Fe3O4 nanoparticles can stabilize butyl butyrate-in-water emulsions, and they also increase the stability of dodecane-in-water emulsions. Thermal gravimetric analysis indicates that the molar quantity of silane reagent is much higher than that of carboxylic acid on nanoparticle surfaces after modification, raising their hydrophobicity and enabling enhanced stability of the resultant polar oil–water emulsions. [Copyright &y& Elsevier]

Abstract: Medical implant-mediated inflammatory responses, often involving high levels of macrophages, are typically determined by histological analyses. These methods however are time consuming and require many animals to monitor the kinetics of inflammatory reactions and to generate reproducible outcomes. Recent studies have shown that activated macrophages in inflamed tissue express high levels of folate receptor (FR). In this study, FR-targeting NIR nanoprobes were fabricated and then tested for their ability to detect and quantify the extent of biomaterial-mediated inflammatory responses in vivo. Indeed, FR-targeting nanoprobes preferentially accumulate on activated macrophage surfaces. When administered intravenously, we found that the FR-targeting nanoprobes distinctively gathered in the inflamed tissues and that a different extent of FR-targeting nanoprobe gathering could be found in tissues implanted with different types of biomaterials. Most importantly, we found that there was a good relationship between the extent of inflammatory reactions and the intensity of nanoprobe-associated NIR signal in tissue. Our results support that FR-targeting NIR nanoprobes can be used to monitor and quantify the extent of macrophage recruitment and the degree of an implants’ biocompatibility in real time. [Copyright &y& Elsevier]

Herein we first report the rapid preparation of monodisperse, clean-surface sub-3 nm intermetallic nanoparticles half-embedded on porous MgO by plasma electrolytic oxidation. Atomic-resolution observation confirms the transformation from disordered solid solution to intermetallics. The nanocatalysts exhibited intermetallic phase-dependent catalytic activity and excellent stability for the reduction of 4-nitrophenol. [ABSTRACT FROM AUTHOR]

• The Sn(OH) 4 are first employed as the anode materials for LIBs, showing higher capacity and longer cycle life. • Mesocarbon microbeads (MCMB) via air-oxidation treatment are acted as the carrier to anchor the ultra-small size Sn(OH) 4. • The discharge mechanisms of Sn(OH) 4 is first proposed according to the CV curves, TEM and XRD characterizations. • The LiOH and carbon can shorten the lithium ion diffusion pathway and buffer the volume expansion and aggregation of Sn. • This composite presents excellent cycling stability and large reversible capacity as an electrode material. SnO 2 -based composites have attracted considerable attention as anode for lithium-ion batteries due to their high theoretical capacity and cost-effectiveness. However, capacity fading often occurs due to the severe volume expansion and cracking during cycling. Herein, ultra-small Sn(OH) 4 nanoparticles have been deposited on the surface of mesocarbon microbeads (MCMB) via a low-temperature air-oxidation treatment. The in-situ oxygenated functional groups from beta-resin on the surface of MCMB lead to the high loading of Sn(OH) 4 nanoparticles with the sizes of 2–3 nm. Interestingly, compared to SnO 2 , the as-prepared Sn(OH) 4 nanoparticles in the composite exhibits a higher reversible specific capacity of 850 mA h g−1 after 50 cycles at a current density of 100 mA g−1. This is because the small sizes of Sn(OH) 4 NPs buffer the large volume expansion and remain stable structure during cycling. The electrochemical reaction mechanism of Sn(OH) 4 is further clarified, in which the generated LiOH can effectively prevent the Sn agglomeration. LiOH also enables the composite to show low diffusion impedance and better electrochemical performance. Therefore, novel Sn(OH) 4 /MCMB composite provides the possibility for practical energy storage devices. [ABSTRACT FROM AUTHOR]

A series of metal ferrite nanocrystals MFe 2 O 4 (M=Fe, Mn, Co, Ni) were prepared via a microwave synthesis strategy. The whole synthesis process could be accomplished in a few minutes at a moderate temperature and without inert gas protecting. The resulting products were systematically characterized and showed uniform spherical morphology with an average particle size of 6.0 nm, well crystallinity, superparamagnetic property and relatively high saturation magnetization. A microwave heating based classical crystallization mode was proposed for the formation of these nanocrystals. This work sheds new light on the synthesis of magnetic nanoparticles with improved properties through a rapid, “green” microwave-assisted synthesis strategy. [ABSTRACT FROM AUTHOR]

• A-site deficient SYTN can be applied as a highly active fuel electrode in SOCs. • The exsolved Ni nanoparticles in SYTN greatly enhanced electrochemical activity of hydrogen. • The R p of SYTN is 0.36 Ω cm2 at 800 °C in 5% H 2 /N 2. A-site deficient Sr 0.9 Y 0.08 Ti 0.95 Ni 0.05 O 3-δ (SYTN) is synthesized and applied as a highly active fuel electrode for reversible solid oxide cells (RSOCs). The as-prepared SYTN shows an n-type conduction mechanism and a high electrical conductivity of 19.7 S cm−1. Based on the density functional theory calculations, it is found that a stronger hybridization of Ni-d and O-p orbit. The exsolved nanoparticles with the perovskite supporter show high catalytic activity. The SYTN anode presents a low R p of 0.36 Ω cm2 at 800 °C in 5% H 2 /N 2. A single cell with SYTN anode and a 170 μm thick Sc 2 O 3 stabilized-ZrO 2 electrolyte layer exhibits maximum power densities of 873 and 412 mW cm−2 at 800 °C using humidified H 2 and CH 4 as fuels respectively. [ABSTRACT FROM AUTHOR]

Along the way to developing highly active catalysts, the fabrication of unique architectures is significant in determining the performance of energy conversion and storage devices. One of the highly competitive options is surface-modified with dispersed nanoparticles by an simply in-situ growth strategy. Typically, the exsolution of active nanoparticles is demonstrated in the irregular powders of perovskite oxides. Here, we report the rational design and fabrication of a porous A-site-deficient titanate fiber decorated by exsolved Ni nanoparticles as a highly efficient and robust fuel electrode for solid oxide cells. We find that the porosity of fiber is one of the pronounced effects on the Ni exsolution. Based on the finite element simulation method and experiments, it is demonstrated that the addition of Gd 0.1 Ce 0.9 O 2 (GDC) in fibrous fuel electrode enhances the contact and connectivity between fibers. This unique microstructure not only provides high specific surface area and more active sites but also benefits to easier mass transfer and charge transfer, resulting in a much lower polarization resistance. The corresponding device shows superior electrochemical performance and durability in humified H 2 (3% H 2 O). This highly active and robust fuel electrode together with the unique architectures lays a strong foundation for designing high-electrochemical active devices. Image 1 • The porous A-site-deficient titanate fibers were decorated by exsolved Ni nanoparticles. • The porosity of fiber is one of the pronounced effects on the Ni exsolution. • The addition of GDC in fibrous anode enhances the ionic conductivity. [ABSTRACT FROM AUTHOR]

• A highly active layered perovskite LSFCu could be used for symmetrical SOCs as the fuel electrode and the oxygen electrode. • The Cu nanoparticles-decorated LSFCu could be simply prepared by a reducing procedure. • The exsolution of Cu in LSFCu is studied via DFT calculations. In this work, we report a highly active Ruddlesden-Popper oxide as a symmetrical electrode for solid oxide cells through in-situ exsolution strategy. The Cu nanoparticles-decorated (LaSr) 0.9 Fe 0.9 Cu 0.1 O 4 (LSFCu) oxide can be simply fabricated by a reducing procedure. The exsolved mechanism of Cu nanoparticle is investigated by the density functional theory (DFT) method. The calculation demonstrates that oxygen releasing is present more energetic in the rocksalt layers, causing the accelerated kinetics of exsolution. The (1 0 0) surface could be the preferential surface for exsolution where take place because of the lowest surface energy. The LSFCu shows a highly electrocatalytic activity as fuel electrode and oxygen electrode simultaneously toward oxygen reduction reaction (ORR) and fuel oxidation reaction (FOR) respectively. In fuel cell (FC) mode, the peak power densities are 573 mW cm−2 and 396 mW cm−2 at 800 °C using humidified H 2 and CH 4 as fuels, respectively. Moreover, a very high current density of 1.02 A cm−2 can also be accomplished at a voltage of 1.2 V in electrolysis cell (EC) mode, implying that this Ruddlesden-Popper oxide decorated by Cu nanoparticles is highly active as the catalyst for the steam electrolysis in symmetrical solid oxide cells. [ABSTRACT FROM AUTHOR]

This work presents the preparation of cross-linking Au nanoparticle (NP) monolayer membranes by the thiol exchange reaction and their enhanced mechanical properties. Dithiol molecules were used as a cross-linking mediator to connect the adjacent nanoparticles by replacing the original alkanethiol ligand in the monolayer. After cross-linking, the membrane integrity was maintained and no significant fracture was observed, which is crucial for the membrane serving as a nanodevice. TEM (Transmission Electron Microscopy), UV–Vis absorption spectrum, and GISAXS (grazing incidence small angle X-ray scattering) were performed to characterize the nanostructure before and after cross-linking. All results proved that the interparticle distance in the monolayer was controllably changed by using dithiols of different lengths as the cross-linking agent. Moreover, the modulus of the cross-linking monolayer was measured by atomic force microscopy (AFM) and the result showed that the membrane with a longer dithiol molecule had a larger modulus, which might derive from the unbroken and intact structure of the cross-linking monolayer due to the selected appropriately lengthed dithiol. This study provides a new way of producing a nanoparticle monolayer membrane with enhanced mechanical properties. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to compare the efficiency of different separation techniques for extracting synovial tissue-derived exosomes. Methods: The synovial tissue discarded during knee arthroscopy or total knee arthroplasty surgery was collected from the Third Affiliated Hospital of Beijing University of Chinese Medicine. Ultracentrifugation (UC), filtration combined with size exclusion chromatography (SECF), and 8% polyethylene glycol (PEG) were used to extract synovial tissue-derived exosomes. Transmission electron microscopy (TEM), nanoparticle tracer analysis (NTA), and Western Blot (WB) were used to detect the morphology, particle size, and biomarker proteins (CD9, CD63, Flotillin-1, and calnexin) of exosomes. Results: The extracts of enriched round and discoid vesicles were successfully extracted with UC, SECF, and PEG. The results of TEM have shown that all three extraction methods can extract circular or elliptical vesicles with disc- and cup-shaped structures from the synovial tissue, with the diameter is about 30–150 nm. NTA suggested the main peaks of three groups of exosomes are around 100–120 nm, and the concentration of the three groups of exosomes was greater than 1 × 1010/ml. The results of WB showed that three positive protein markers (CD9, CD63, and Flotillin-1) were highly expressed in the suspension extracted by the three methods and low in the synovial tissue. However, the negative protein (calnexin) was highly expressed in synovial tissues and PEG group, while low in UC and SECF group. Conclusion: Morphology, particle size, and labeled protein marker detection confirmed that UC, SECF, and PEG can extract exosomes derived from synovial tissue; UC and SECF are more recommended for the extraction of synovial tissue-derived exosomes, which provides a methodological basis for studying the function and mechanism of synovial tissue exosomes in the future. [ABSTRACT FROM AUTHOR]

The heat transfer from nanoparticles (NPs) to gas of photothermal effect is investigated by taking into account both conduction and radiation. The steady-state and unsteady-state heat transfer processes are studied analytically and numerically, respectively. In contrast to the photothermal effect in liquid with metal NPs, in which the radiation is negligible, we found that the thermal radiation must be taken into account in the nanoparticle–gas system. The reason is that the thermal boundary conductance (TBC) of gas–solid interface is several orders of magnitude smaller than the TBC of liquid–solid interface, especially when the diameter of nanoparticle is comparable to or smaller than the mean free path of gas molecules. We propose a method to measure the ultra-low TBC of interface between nanoparticle and gas based on our investigations. [ABSTRACT FROM AUTHOR]

• The study proposes a new preparation system, micro-plasma electrolytic oxidation. • Au/MgO with defects is fabricated by combining liquid nitrogen as cooling source. • Au/MgO exhibits an excellent catalytic activity in nitrophenol hydrogenation. The defect-rich Au nanoparticles (NPs) catalyst on Mg surface was prepared by the micro-plasma electrolyte oxidation (MPEO) utilizing liquid nitrogen as the cooling medium. MPEO is a high-temperature plasma oxidation process that decomposes the [AuCl 4 ]-precursor salt to form metastable state Au NPs. The rapid quenching effect of liquid nitrogen occurs during this non-equilibrium process and generates numerous defects on the Au NPs, thereby altering their electronic state. Consequently, the catalytic performance of this Au/MgO catalyst was outstanding, exceeding that of the sample prepared without using liquid nitrogen. This finding indicates that the harsh environment plays a crucial role in producing defect-rich Au NPs and improving the catalytic efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amorphous Fe–Mn binary oxide nanoparticles decorated bamboo monolith (Fe–Mn–O/MB) were synthesized. • Fe–Mn–O/MB are highly effective for aqueous As(III) and As(V) removal. • The adsorbent has the dual function of "oxidation (Mn(IV))-adsorption (Fe(III))". • Surface complexation was the dominant removal mechanism. • Fe–Mn–O/MB reduced As concentration to less than 10 μg L−1 in column system for 1150 BV. The removal of naturally occurring arsenic from aqueous media remains a challenging endeavor for the protection of public health and ecosystems. Herein, we devised a workable fresh-biomass-based monolith adsorbent by in situ generation of amorphous Fe–Mn binary oxides nanoparticles (Fe–Mn–O) on a waste bamboo biomass (MB) via a simple procedure of pre-oxidation plus co-precipitation. In the pre-oxidation process of MB, the surface underwent roughening and the manganese ions permeated deeply inside the biomass, both of which facilitated the loading of Fe–Mn–O (25.06 wt%). As a result, the Fe–Mn–O/MB had outstanding adsorption capacities of 33.41 and 36.88 mg g−1 for As(III) and As(V), respectively. XRD and FTIR analyses show that the amorphous structure of Fe–Mn–O with low-coordinated active centers provides numerous hydroxyl functional groups that enhance arsenic adsorption, moreover, oxidation of As(III) was realized. In different water matrix, the Fe–Mn–O/MB composite exhibited a retention of 87.33 % and 89.53 % of its original adsorption capacity for As(III) and As(V) after five cycles of reuse as well as enabled continuous operation in a fixed-bed system with a bed volume of around 1150. Therefore, this work provides a promising approach for efficient abatement of inorganic arsenic-caused water pollution. [ABSTRACT FROM AUTHOR]

Multifunctionalized thionine-modified cerium oxide (Thi–CeO2) nanostructures with redox ability and catalytic activity were designed as the bionanolabels for in situ amplified electronic signal of low-abundance protein (carcinoembryonic antigen, CEA, used as a model) based on a cerium oxide-triggered ‘one-to-many’ catalytic cycling strategy. Initially, the carried CeO2 nanoparticles autocatalytically hydrolyzed the phosphate ester bond of l-ascorbic acid 2-phosphate (AAP) to produce a new reactant (l-ascorbic acid, AA), then the generated AA was electrochemically oxidized by the assembled thionine on the Thi–CeO2, and the resultant product was then reduced back to AA by the added tris(2-carboxyethy)phosphine (TCEP). The catalytic cycling could be re-triggered by the thionine and TCEP, resulting in amplification of the electrochemical signal. Under the optimized conditions, the electrochemical immunosensor exhibited a wide linear range of 0.1 pg mL−1 to 80 ng mL−1 with a low detection limit of 0.08 pg mL−1 CEA at the 3σblank level. In addition, the methodology was evaluated for the analysis of clinical serum samples, and was in good accordance with values obtained using the commercialized enzyme-linked immunosorbent assay (ELISA) method. [ABSTRACT FROM AUTHOR]

Abstract: Experimental methods targeting molecules or drugs to specific neuronal tissue(s) can be important in determining function. In this study we focused on blockade of the small channel or aqueduct connecting the third and fourth ventricles of the rat brain. A cannula was placed into the aqueduct between the third and fourth ventricle. A second cannula was placed into the third or fourth ventricle. An aqueous dispersion of hydrogel nanoparticles, that maintains a liquid state at temperatures below 33 °C and solidifies near body temperature (35 °C), was infused into the aqueduct. Two interpenetrating polymer networks (IPN) of hydrogel nanoparticles with polymer concentrations at 2% by weight and 3% by weight were separately infused into the aqueduct to block cerebrospinal fluid (CSF) flow. Following infusion of hydrogel CSF was isolated to a particular ventricle as shown by the lack of dye movement between the ventricles. In addition, stress hormone, corticosterone, feeding behavior and blood glucose levels were measured. Results show upon reaching the aqueduct the hydrogel dispersion solidified and restricted the flow of CSF. A higher concentration of dispersion (3% wt.) was more effective in blocking the aqueduct and isolating the third from the fourth ventricle. Over the period of measurement, infusion of the dispersion had no measurable detrimental physiological effects on the animal. We conclude that isolation of ventricles in the brain can be completed for 48-h by using dispersions of hydrogel nanoparticles and the effects of drugs on certain brain tissues can be determined with this method. [Copyright &y& Elsevier]

Surface-enhanced Raman scattering (SERS) technique is a powerful spectrum analysis technique for the ultra-low molecular trace detection. Conventionally, noble metals like silver (Ag) and gold (Au) are used to prepare the SERS substrates; however, limitations of complicated experimental designs and sophisticated process steps impede their wide applications in practice. Recently, metal oxides arise as a promising material for SERS application, but relatively weak Raman signal enhancement and poor material stability still pose as a challenge. Here, a UV-light-assisted fabrication of MoO3−x/silver nanoparticles (MoO3−x/Ag NPs) film is proposed. In the experiment, the sub-transition-metal-oxide of MoO3−x was used as the Raman chemical enhancement substrate as well as the reducing agent. Through the spin-coating of MoO3−x layer on the silicon substrate and UV-light-assisted reduction of silver nitride (AgNO3) on the MoO3−x layer, a novel MoO3−x/Ag NPs one-layer film was fabricated. Using the Rhodamine B (RhB) as the Raman reporter, SERS measurement shows that enhancement factor (EF) of 1.195 × 106 could be achieved. Moreover, a Raman signal amplifying strategy is further demonstrated by constructing MoO3−x/Ag NPs multi-layer films. And result evidences that maximum gain of 2.07 for the RhB Raman peak at 1280 cm−1 can be obtained on the MoO3−x/Ag NPs three-layer film when referred to that on the MoO3−x/Ag NPs one-layer film. Meanwhile, the EF of the MoO3−x/Ag NPs three-layer film is also improved to 2.985 × 106, giving the minimum detectable concentration of 10−9 M. [ABSTRACT FROM AUTHOR]

The spread of SARS-CoV-2 virus in the ongoing global pandemic has led to infections of millions of people and losses of many lives. The rapid, accurate and convenient SARS-CoV-2 virus detection is crucial for controlling and stopping the pandemic. Diagnosis of patients in the early stage infection are so far limited to viral nucleic acid or antigen detection in human nasopharyngeal swab or saliva samples. Here we developed a method for rapid and direct optical measurement of SARS-CoV-2 virus particles in one step nearly without any sample preparation using a spike protein specific nanoplasmonic resonance sensor. As low as 370 vp/mL were detected in one step within 15 min and the virus concentration can be quantified linearly in the range of 0 to 107 vp/mL. Measurements shown on both generic microplate reader and a handheld smartphone connected device suggest that our low-cost and rapid detection method may be adopted quickly under both regular clinical environment and resource-limited settings. Image 1 • 15min one step SARS-CoV-2 viral particles detection. • No sample processing and low-cost equipment and biosensor chip. • Sensitive for asymptomatic carriers diagnosis potentially. [ABSTRACT FROM AUTHOR]

Metallic nanoparticles are used in every stage of science and are still charming the researchers to explore the localized surface plasmon resonance (LSPR) properties for the promising application of sensors and catalysts. In this review, recent progresses on silver-based and gold-based single nanoparticle for resonance light scattering imaging analysis and applications are presented. Firstly, fundamental principles and technique of dark-field microscope (DFM) coupled the LSPR spectroscopy are described. Then, the species of silver-based and gold-based single nanoparticle are outlined, with an emphasis on the resonance light scattering imaging analysis of silver-based and gold-based single nanoparticle. Finally, recent achievements of the plasmonic single-particle imaging analysis technique in analytical determinations and reaction monitoring are also comprehensively introduced. We hope to shed some light on the forthcoming study by showing these advances and some future challenges of resonance light scattering imaging analysis. • This review extracts the key principles from literature for the resonance light scattering imaging to comprehensively understand the mechanism. • The resonance light scattering imaging analysis of silver-based and gold-based diverse single nanoparticle was comprehensively introduced. • The challenges and perspectives in exploration, development, and practical applications were presented. [ABSTRACT FROM AUTHOR]

This study reports an ultrasound-mediated and two-dimensional (2D) porous vermiculite nanosheets (VMT NSs)-based nanocatalyst platform (Arg@VMT@PDA-PEG) that synergistically harnessed the Fenton reaction-based chemodynamic therapy (CDT), 2D semiconductor-based sonodynamic therapy (SDT) and nitric oxide (NO)-based gas therapy for combination cancer therapy. The tumor microenvironment responsive degradation of polydopamine (PDA) shell could not only prevent L-Arg, a NO donor, leakage during blood circulation, but also selectively release the active sites of VMT NSs for catalytic reactions in tumor cells. Additionally, the Fenton reactions mediated by the abundant Fe2+/Fe3+ in VMT NSs could efficiently produce ·OH and consume glutathione (GSH) for CDT. Moreover, the reactive oxygen species (ROS, ·OH and ·O 2 −) produced by ultrasound-triggered Arg@VMT@PDA-PEG could not only execute SDT but also oxidize L-Arg to NO for synergetic gas therapy. The results show that the transformation of ROS to NO can enhance curative efficacy owing to the ability of NO with much longer life-time in freely diffusing into cells from intercellular space. This biodegradable Arg@VMT@PDA-PEG nanocatalytic platform integrating three different catalytic reactions provides a new therapeutic paradigm for combination cancer therapy. [Display omitted] [ABSTRACT FROM AUTHOR]

A new three-dimensional (3D) nanoporous ZnWO 4 nanoparticles with WCl 6 and Zn(NO 3 ) 2 ·6H 2 O as the precursors was prepared by electrospinning through a simple and facile progress of electrospinning. The 3D nanoporous ZnWO 4 nanoparticles(3DN ZnWO 4 ) were used as the electrode for supercapacitor application, and the electrochemical performance was analyzed, indicating the 3DN ZnWO 4 supercapacitor is an ideal electrode material with an outstanding cycle, high specific capacitance and excellent rate capacitance, especially it can resist a high current charge and discharge with a little capacitance fading(specific capacitance decreases only 10% with the current density being increased from 40 A g −1 to 100 A g −1 ). [ABSTRACT FROM AUTHOR]

We report on the fluorescence enhancement induced by gold nanoparticles (Au NPs) deposited on porous silicon Bragg reflectors (Bragg PS). The rhodamine 6 G (R6G) fluorescence was studied on single-layer porous silicon films and porous silicon Bragg reflectors. By comparison, R6G fluorescence of porous silicon films with Au NPs infiltrated is about two times that of porous silicon films without Au NPs. The R6G fluorescence of this porous silicon Bragg reflectors with Au NPs infiltrated is also stronger than the single-layered porous silicon films (∼2.3-fold) with Au NPs infiltrated. Such substrates with a multiple enhancement of the fluorescence have great potential for applications in the fields of medical diagnostics and biotechnology. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a chemical-flame spheroidizing method was proposed to facilely prepare low radioactivity spherical silicon oxide powders. Firstly, the rice husks, composed of silicon oxide frame, were employed as the raw materials to prepare high-purity colloidal silica nanoparticles with the size 24nm via a simple “pyrolyzation–ashing–dissolvation” process. Then, the silica colloid was further treated by a spraying–drying process to mainly form mushroomhead-shaped silica particles with particle size 0.5–10μm. Most of the powders were hollow, the thickness of the walls of hollow silicon oxide powders was about 50–100nm. The surfaces were rough, the powders had poor fluidity and the apparent density was only 0.21g/cm3. Finally, almost all these submicro and microparticles were densified by an oxygen–acetylene flame spheroidizing process to get low radioactivity spherical silicon oxide powders with the size 0.5–5μm. The fluidity, the apparent density and the content of U of the as-prepared spherical silicon oxide powders reached 94s/50g, 0.721g/cm3 and 0.05×10−9g/g, respectively. Such silicon oxide material originating from rice husks could potentially be used in very large scale integration field. [Copyright &y& Elsevier]

Objectives The aim was to prepare novel Ganoderma lucidum polysaccharide nanoparticles and to evaluate the physicochemical properties and anti-tumour activity in in-vitro cytotoxicity studies using HepG2, HeLa and A549 cancer cell lines, and growth promotion effects on mouse spleen cells. Methods Chitosan nanoparticles loaded with G. lucidum polysaccharide were prepared using the ion-revulsion method. The diameter distribution of the particles and the surface charge were measured using a zetasizer analyser. The entrapment efficiency and drug loading capacity were examined by the diethylaminoethanol weak anion exchange method. The cytotoxic effects of nanoparticles on tumour cells and the growth promotion effects on mouse spleen cells were tested using the MTT assay. Key findings Nanoparticles loaded with G. lucidum polysaccharide at 6 μg/ml and chitosan/sodium tripolyphosphate (mass) ratio of 5.5 had significantly greater cytotoxic effects on tumour cells and growth promotion effects on mouse spleen cells than empty nanoparticles. Conclusions G. lucidum polysaccharide nanoparticles showed significant anti-tumour efficacy, having both cytotoxic effects on tumour cells and growth promotion effects on spleen cells, making it a promising candidate in the clinical setting. [ABSTRACT FROM AUTHOR]

Abstract: β-In2S3 nanofibers were successfully synthesized via a hydrothermal method with AAO membrane as a template at 150°C for 15h. XRD patterns indicated the perfect crystallization of β-In2S3. SEM images showed that the β-In2S3 nanofibers grew up from the channel ends of the AAO template. TEM images confirmed that the nanofibers had a high aspect ratio of ca. 40–50 and diameters of about 10nm. The room temperature photoluminescence (PL) spectrum of the β-In2S3 nanofibers indicated its potential applications in light-emission devices. [Copyright &y& Elsevier]

Abstract: Cadmium tungstate (CdWO4) nanoparticles and nanorods have been successfully synthesized by a molten salt method at 270°C, and the morphology of the nanocrystals can be controlled by adjusting such reaction conditions as the calcined time and the weight ratio of the salt to the CdWO4 precursor. The resultant sample is a pure phase of CdWO4 without any other impurities. [Copyright &y& Elsevier]

Abstract: Nanometer-sized Bi4Ti3O12 particles have been prepared by chemical reaction of bismuth nitrate pentahydrate, titanium sulfate and ammonia solution in a reverse microemulsion system consisting of water, OP (P-octyl polyethylene glycol phenylether, non-ionic surfactant), n-butanol (co-surfactant), and cyclohexane (oil). Precursor hydroxides precipitated in the droplets of water-in-oil (w/o) microemulsion were calcined at 800°C for 4h to form Bi4Ti3O12 nanoparticles. The samples were investigated with X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared spectrophotometer (FT-IR) and ultraviolet visible spectrophotometer (UV–vis). It was found that the as-prepared Bi4Ti3O12 nanoparticles had small particle sizes (35nm), high crystallinity, narrow size distributions and strong light absorption properties not only in the ultraviolet light but also in the visible light region. [Copyright &y& Elsevier]

• The bioanode of mixed culture in-situ synthesized iron sulfide nanoparticles in MFC. • The amorphous nanoparticles, comprising of FeS and FeS 2 , promoted electron transfer. • The nanoparticles coated on bacteria and self-organized a 3D conductive cell network. • The thick "shell" on bacteria formed by nanoparticles inhibited cell viability. • Some electroactive and sulfur reducing bacteria were specifically enriched on anode. The bioanode of mixed consortia was for the first time used to in-situ synthesize iron sulfide nanoparticles in a microbial fuel cell (MFC) over a long-term period (46 days). These poorly crystalline nanoparticles with an average size of 29.97 ± 7.1 nm, comprising of FeS and FeS 2 , significantly promoted extracellular electron transfer and thus the electricity generation of the MFC. A maximum power density of 519.00 mW/m2 was obtained from the MFC, which was 1.92 times as high as that of the control. The cell viability was promoted by a small amount of iron sulfide nanoparticles but inhibited by the thick nanoparticle "shell" covered on the bacterial cells. Some electroactive and sulfur reducing bacteria (eg. Enterobacteriaceae , Desulfovibrio , and Geobacter) were specifically enriched on the anode. This study provides a novel insight for improving the performance of bioelectrochemical systems through in-situ sustainable nanomaterials biofabrication by mixed consortia. [ABSTRACT FROM AUTHOR]

Abstract: CaMoO4 nanoparticles were successfully synthesized by a molten salt method at a temperature as low as 270°C. The as-prepared powders, characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), exhibited a pure CaMoO4 phase about 70nm in particle size and uniform nearly-spherical particle shape. The room temperature luminescent spectra were performed on a Fluorolog-3 spectrofluorometer; the powders exhibited green emission peaks of 508nm. The molten salt medium could speed up the diffusion rates of the reaction ions, and thus decrease greatly the synthesis temperature of CaMoO4 nanoparticles. [Copyright &y& Elsevier]

• Self-toughness porous Si 3 N 4 ceramics with 3D cage structures are prepared. • 3D cage structures can cause crack deflection to produce microcrack toughening. • No metallic oxide sintering aids exist in the as-fabricated porous Si 3 N 4 ceramics. • Si 3 N 4 ceramics own high mechanical strength and excellent dielectric properties. Self-toughness porous Si 3 N 4 ceramics are prepared by surface modification of Si 3 N 4 particles. The as-fabricated porous Si 3 N 4 ceramics have high number of three-dimensional cage structures that can cause the crack deflection, absorb the fracture stress to produce microcrack toughening effect and increase the structural reliability of porous Si 3 N 4 ceramics. The flexural strength is 78.0 MPa. The dielectric constant and dielectric loss is 3.47 and 0.001 respectively. This kind of porous Si 3 N 4 ceramics with special three-dimensional cage structures have high mechanical strength, good antioxidation properties and excellent dielectric properties. [ABSTRACT FROM AUTHOR]

• Two nanoparticles of amphipathic tetracene with different PEG lengths have been prepared with simple re-precipitation method. • Singlet fission can be conducted in these two nanoparticles via a real charge-transfer intermediate state. • Longer PEG chain will lead a reduced interaction in nanoparticle and thus a lower singlet fission yield. Two tetracene derivatives with PEG group of different lengths (PhTc-PEG-1 with short PEG chain and PhTc-PEG-2 with long PEG chain) have been synthesized and fabricated into nanoparticles with re-precipitation method. Spherical nanoparticle is formed for these two compounds in water as revealed by scanning electron microscopy. Steady-state absorption and fluorescence spectra demonstrates that the interaction between the adjacent tetracene units in these two nanoparticles is relatively strong, but the interaction in PhTc-PEG-2 nanoparticle is weaker than that of PhTc-PEG-1 nanoparticle. Transient absorption experiment reveals that singlet fission (SF) can be conducted in these two nanoparticles via a real charge-transfer (CT) intermediate state resembled that in same tetracene core without PEG chain (PhTc). However, the SF yields of these nanoparticles are relatively low, suggesting that the formation of the real CT state is unfavorable for the occurrence of SF. Moreover, the weaker interaction in PhTc-PEG-2 nanoparticle leads to a relatively low SF yield compared to that of PhTc-PEG-1 nanoparticle, suggesting that the long PEG chain should be avoided when modifying SF chromophore for preparing colloidal nanoparticles with the goal of achieving efficient SF. [ABSTRACT FROM AUTHOR]

Abstract: CaWO4 nanoparticles were synthesized by a molten salt method at a low temperature as 200 °C. The as-prepared powders were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), and exhibited a pure tetragonal phase CaWO4 with a scheelite structure about 20 nm in size with uniform and nearly spherical or elongated grain shape. The molten salt medium could speed up the diffusing rates of the reaction ions, and thus decrease greatly the synthetic temperature of CaWO4 nanoparticles. It is rational to expect that some other nanoscale materials, which easily vaporize at high temperature, may be synthesized by this method. [Copyright &y& Elsevier]