Accelerated Wound Healing by Electrospun Multifunctional Fibers with Self-Powered Performance.

Wound healing has been a persistent clinical challenge for a long time. Electrical stimulation is an effective therapy with the potential to accelerate wound healing. In this work, the self-powered electrospun nanofiber membranes (triples) were constructed as multifunctional wound dressings with electrical stimulation and biochemical capabilities. Triple was composed of a hydrolyzable inner layer with antiseptic and hemostatic chitosan, a hydrophilic core layer loaded with conductive AgNWs, and a hydrophobic outer layer fabricated by self-powered PVDF. Triple exhibited presentable wettability and acceptable moisture permeability. Electrical performance tests indicated that triple can transmit electrical signals formed by the piezoelectric effect to the wound. High antibacterial activities were observed for triple against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, with inhibition rates of 96.52, 98.63, and 97.26%, respectively. In vitro cell assays demonstrated that triple cells showed satisfactory proliferation and mobility. A whole blood clotting test showed that triple can enhance hemostasis. The innovative self-powered multifunctional fibers presented in this work offer a promising approach to addressing complications and expediting the promotion of chronic wound healing.

PtCuRu Nanoflowers with Ru-Rich Edge for Efficient Fuel-Cell Electrocatalysis.

Enhancing the catalytic activity of Pt-based alloy by a rational structural design is the key to addressing the sluggish kinetics of direct alcohol fuel cells. Herein, a facile one-pot method is reported to synthesize PtCuRu nanoflowers (NFs). The synergetic effect among Pt, Cu, and Ru can lower the d-band center of Pt, regulate the morphology, generate Ru-rich edge, and allow the exposure of more high index facets. The optimized Pt0.68 Cu0.18 Ru0.14 NFs exhibit outstanding electrocatalytic performances and excellent anti-poisoning abilities. The specific activities for the methanol oxidation reaction (MOR) (7.65 mA cm-2 ) and ethanol oxidation reaction (EOR) (7.90 mA cm-2 ) are 6.0 and 7.1 times higher than commercial Pt/C, respectively. The CO stripping experiment and the chronoamperometric (5000 s) demonstrate the superior anti-poisoning property and durability performance. Density functional theory calculations confirm that high metallization degree leads to the decrease of d-band center, the promotion of oxidation of CO, and improvement of the inherent activity and anti-poisoning ability. A Ru-rich edge exposes abundant high index facets to accelerate the reaction kinetics of rate-determining steps by decreasing the energy barrier for forming *HCOOH (MOR) and CC bond breaking (EOR).

The development of a candidate of desensitization vaccines against Der f 2 nearly without IgE-binding activity.

Considering the important role of Der f 2 in house dust mites mediating allergic diseases and allergic adverse effects during allergen-specific immunotherapy (AIT), we intend to develop a candidate of desensitization vaccines against Der f 2 without allergenicity. According to the reported immunoglobulin E (IgE)-binding B and T cell epitopes of Der f 2, four candidates of desensitization vaccines against Der f 2 were developed. Recombinant wild-type Der f 2 (rWt-Der f 2) preserved conformational and linear IgE-binding B epitopes. rWt-Der f 2 linearized by reduction and alkylation reactions (rWt-Der f 2 (red/alk)) and recombinant modified-type Der f 2 (rMt-Der f 2) were developed via destroying conformational and linear IgE-binding B epitopes respectively. rMt-Der f 2 linearized by reduction and alkylation reactions (rMt-Der f 2 (red/alk)) was developed by destroying conformational and linear IgE-binding B epitopes. T cell epitopes of 4 candidates were preserved. The change of their IgE-binding activity was determined by enzyme linked immunosorbent assay (ELISA), western blot and inhibition ELISA. Compared with rWt-Der f 2, the IgE-binding activity of rWt-Der f 2 (red/alk), rMt-Der f 2 and rMt-Der f 2 (red/alk) all decreased, which was consistent with the result of western blot. The IgE-binding activity of rMt-Der f 2 and rMt-Der f 2 (red/alk) was not significantly different (P = 0.0863 > 0.05), which was comparable to that of their corresponding negative controls (P = 0.3488 and 0.4459, both > 0.05). The result of inhibition ELISA also showed that their IgE-binding activity decreased, and rMt-Der f 2 (red/alk) was the lowest. Conclusively, we developed the candidate of desensitization vaccines against Der f 2, rMt-Der f 2 or rMt-Der f 2 (red/alk), nearly without allergenicity, which would potentially prevent HDM allergic patients from allergic adverse effects caused by AIT.

N-Doped MoS2 Nanoflowers for Efficient Cr(VI) Removal.

The removal of Cr(VI) has attracted extensive attention since it causes serious harm to public health. Herein, we report a two-step method to synthesize N-doped MoS2 nanoflowers (NFs) with controllable sizes, which are first utilized for Cr(VI) removal and display outstanding removal performance. The N-MoS2 NFs with an average size of 40 nm (N-MoS2 NFs-40 nm) can rapidly remove Cr(VI) in 15 min under optimal conditions. The maximum adsorption capacity of N-MoS2 NFs-40 nm can reach 787.41 mg·g-1, which is significantly larger than that of N-MoS2 NFs-150 and -400 nm (314.46 and 229.88 mg·g-1). Meanwhile, N-MoS2 NFs-400 nm have a higher maximum adsorption capacity than pure MoS2 NFs-400 nm (172.12 mg·g-1). In this adsorption/reduction process, N-MoS2 NFs have abundant adsorption sites due to a high surface area. N doping can generate more sulfur vacancy defects in the MoS2 NF structure to accelerate electron transfer and enhance the reduction of Cr(VI) to low-toxicity Cr(III). This study provides a facile approach to fabricating N-MoS2 nanoflowers and demonstrates their superior removal ability for Cr(VI).

Promotion of the Co3O4/TiO2 Interface on Catalytic Decomposition of Ammonium Perchlorate.

Supports can widely affect or even dominate the catalytic activity and selectivity of nanoparticles because atomic geometry and electronic structures of active sites can be regulated, especially at the interface of nanoparticles and supports. However, the underlying mechanisms of most systems are still not fully understood yet. Herein, we construct the interface of Co3O4/TiO2 to boost ammonium perchlorate (AP) catalytic decomposition. This catalyst shows enhanced catalytic performance. With the addition of 2 wt % Co3O4/TiO2 catalysts, AP decomposition peak temperature decreases from 435.7 to 295.0 °C and activation energy decreases from 211.5 to 137.7 kJ mol-1. By combining experimental and theoretical studies, we find that Co3O4 nanoparticles can be strongly anchored onto TiO2 supports accompanied by charge transfer. Moreover, at the interfaces in the Co3O4/TiO2 nanostructure, NH3 adsorption can be enhanced through hydrogen bonds. Our research studies provide new insights into the promotion effects of the nanoparticle/support system on the AP decomposition process and inspire the design of efficient catalysts.

Can Masks Be Reused After Hot Water Decontamination During the COVID-19 Pandemic?

Masks have become one of the most indispensable pieces of personal protective equipment and are important strategic products during the coronavirus disease 2019 (COVID-19) pandemic. Due to the huge mask demand-supply gap all over the world, the development of user-friendly technologies and methods is urgently needed to effectively extend the service time of masks. In this article, we report a very simple approach for the decontamination of masks for multiple reuse during the COVID-19 pandemic. Used masks were soaked in hot water at a temperature greater than 56 °C for 30 min, based on a recommended method to kill COVID-19 virus by the National Health Commission of the People's Republic of China. The masks were then dried using an ordinary household hair dryer to recharge the masks with electrostatic charge to recover their filtration function (the so-called "hot water decontamination + charge regeneration" method). Three kinds of typical masks (disposable medical masks, surgical masks, and KN95-grade masks) were treated and tested. The filtration efficiencies of the regenerated masks were almost maintained and met the requirements of the respective standards. These findings should have important implications for the reuse of polypropylene masks during the COVID-19 pandemic. The performance evolution of masks during human wear was further studied, and a company (Zhejiang Runtu Co., Ltd.) applied this method to enable their workers to extend the use of masks. Mask use at the company was reduced from one mask per day per person to one mask every three days per person, and 122 500 masks were saved during the period from 20 February to 30 March 2020. Furthermore, a new method for detection of faulty masks based on the penetrant inspection of fluorescent nanoparticles was established, which may provide scientific guidance and technical methods for the future development of reusable masks, structural optimization, and the formulation of comprehensive performance evaluation standards.

Surfactant-Free Aqueous Dispersions of Shape- and Size-Controlled Zirconia Colloidal Nanocrystal Clusters with Enhanced Photocatalytic Activity.

Colloidal nanocrystal clusters (CNCs) are formed by clustering nanocrystals into secondary structures, which represent a new class of materials and have attracted considerable attention, owing to their unique collective properties and novel functionalities achieved from the ensembles in addition to the properties of each individual subunit. Here, we design a simple route to prepare aqueous dispersions of highly stable ZrO2 CNCs with tunable shape and size without modification. ZrO2 CNCs are composed of many ZrO2 nanocrystals each with a size of about 7 nm and possess a mesoporous structure. Both cube-like and star-like shapes of CNCs can be achieved by using different alkaline sources, while the size of CNCs can be adjusted by changing the hydrothermal time. The as-prepared aqueous dispersions of ZrO2 CNCs display an enhanced photocatalytic activity in the degradation of rhodamine B (RhB), compared with ZrO2 nanodispersions. More interestingly, star-like ZrO2 CNCs show better photocatalytic degradation properties than those of cube-like counterparts and even commercial P25. Furthermore, ZrO2 CNCs are easily recycled and can be used for the degradation of a range of dye systems.

Synthesis of Transparent Aqueous ZrO2 Nanodispersion with a Controllable Crystalline Phase without Modification for a High-Refractive-Index Nanocomposite Film.

The controllable synthesis of metal oxide nanoparticles is of fundamental and technological interest. In this article, highly transparent aqueous nanodispersion of ZrO2 with controllable crystalline phase, high concentration, and long-term stability was facilely prepared without any modification via the reaction of inexpensive inorganic zirconium salt and sodium hydroxide in water under an acid surrounding, combined with hydrothermal treatment. The as-prepared transparent nanodispersion had an average particle size of 7 nm, a high stability of 18 months, and a high solid content of 35 wt %. ZrO2 nanocrystals could be readily dispersed in many solvents with high polarity including ethanol, dimethyl sulfoxide, acetic acid, ethylene glycol, and N, N-dimethylformamide, forming stable transparent nanodispersions. Furthermore, highly transparent polyvinyl alcohol/ZrO2 nanocomposite films with high refractive index were successfully prepared with a simple solution mixing route. The refractive index could be tuned from 1.528 to 1.754 (@ 589 nm) by changing the mass fraction (0-80 wt %) of ZrO2 in transparent nanocomposite films.

Synthesis of transparent dispersions of aluminium hydroxide nanoparticles.

Transparent dispersions of inorganic nanoparticles are attractive materials in many fields. However, a facile method for preparing such dispersions of aluminium hydroxide nanoparticles is yet to be realized. Here, we report a direct reactive method to prepare transparent dispersions of pseudo-boehmite nanoparticles (1 wt%) without any surface modification, and with an average particle size of 80 nm in length and 10 nm in width, as well as excellent optical transparency over 94% in the visible range. Furthermore, transparent dispersions of boehmite nanoparticles (1.5 wt%) were also achieved after an additional hydrothermal treatment. However, the optical transparency of dispersions decreased with the rise of hydrothermal temperature and the shape of particles changed from rhombs to hexagons. In particular, monodisperse hexagonal boehmite nanoplates with an average lateral size of 58 nm and a thickness of 12.5 nm were obtained at a hydrothermal temperature of 220 °C. The selectivity of crystal growth direction was speculated as the possible formation mechanism of these as-prepared aluminium hydroxide nanoparticles. Besides, two values of 19.6 wt% and 14.64 wt% were separately measured for the weight loss of pseudo-boehmite and boehmite nanoparticles after a continuous heating, indicating their potential flame-resistant applications in the fabrication of plastic electronics and optical devices with high transparency.

Transparent 'solution' of ultrathin magnesium hydroxide nanocrystals for flexible and transparent nanocomposite films.

Transparent solutions of nanocrystals exhibit many unique properties, and are thus attractive materials for numerous applications. However, the synthesis of transparent nanocrystal solutions of magnesium hydroxide (MH) with wide applications is yet to be realized. Here, we report a facile two-step process, which includes a direct reactive precipitation in alcohol phase instead of aqueous phase combined with a successive surface modification, to prepare transparent alcohol solutions containing lamellar MH nanocrystals with an average size of 52 nm and an ultrathin thickness of 1-2 nm, which is the thinnest MH nanoplatelet reported in the literatures. Further, highly flexible and transparent nanocomposite films are fabricated with a solution mixing method by adding the transparent MH nanocrystal solutions into PVB solution. Considering the simplicity of the fabrication process, high transparency and good flexibility, this MH/polymer nanocomposite film is promising for flame-resistant applications in plastic electronics and optical devices with high transparency, such as flexible displays, optical filters, and flexible solar cells.

[Cutting propagation of Periploca forrestii and dynamic analyses of physiological and biochemical characteristitics related to adventitious roots formation].

OBJECTIVE: To study the effects of different auxcin regulators on rooting of Periplocaforrestii cuttings as well as dynamic change rules of endogenous plant hormones and oxidases related to adventitious root formation. METHODS: Cuttings propagation characters of Periploca forrestii were investigated and compared with different concentration treatments of indolebutyric acid (IBA), Rooting Powder No. 1 (ABT1) and naphthylacetic acid (NAA). The dynamic changes of contents of endogenous hormones including indole acetic acid (IAA), abscisic acid (ABA), zeatin ribosides (ZRs) as well as the activities of indoleacetic acid oxidase( IAAO), polyphenol oxidase (PPO), peroxidase (POD) were tested. RESULTS: Rooting percentage of cutting with 150 mg/L IBA, 150 mg/L ABT1 treatment and NAA treatment were 80% ,70% and 68% respectively, rooting percentage of cuttings of the control was 23% only. The adventitious rooting displayed three distinct phases i. e. root-inducing, root-formating and root-elongating phases. During root-inducing phase the contents of IAA, ABA and ZRs decreased,whereas IAAO activity kept at a higher level. The IAA content reached the peak and PPO activity increased obviously during root-formating phase, while activities of IAAO, POD and contents of ABA, ZRs declined to minimum. During root-elongating phase contents of IAA, ABA, ZRs were much steadfast and activities of PPO, IAAO, POD were increased. After that, the activities of the three oxidases decreased slowly. 150 mg/L IBA treatment increased the content of IAA and PPO activity in cuttings during rooting,while the opposite result occurred in contents of ZRs, ABA and the activities of IAAO, POD. CONCLUSION: The dynamic changes of endogenous hormones (IAA, ABA, ZRs) contents and IAAO, PPO, POD activities are tightly related to the rooting process of cuttings in Periploca forrestii.

Microfluidic synthesis of monodisperse Cu nanoparticles in aqueous solution.

The continuous production of Cu nanoparticles with a particle size of 2-5 nm was conducted by sodium borohydride reduction of copper sulfate in aqueous solution in a tube-in-tube microchannel reactor (TMR), which consists of an inner tube and an outer tube with the reaction performed in the annular microchannel between these two tubes. The as-prepared Cu nanoparticles were compared with those obtained by a conventional batch synthesis process by using transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis spectroscopy. Due to the highly intensified micromixing effects in the TMR, Cu nanoparticles prepared by this route exhibits a smaller particle size, narrower size distribution and better stability in air. The TMR shows an excellent ability of preparing high-quality Cu nanoparticles in mild conditions. In addition, with the unique microchannel structure, the throughput capability of the TMR for the production of Cu nanoparticles is up to several liters per minute.

Discovery of novel fatty acid synthase (FAS) inhibitors based on the structure of ketoaceyl synthase (KS) domain.

Development of fatty acid synthase (FAS) inhibitors has increasingly attracted much attention in recent years due to their potential therapeutic use in obesity and cancers. In this investigation, pharmacophore modeling based on the first crystal structure of human KS domain of FAS was carried out. The established pharmacophore model was taken as a 3D query for retrieving potent FAS inhibitors from the chemical database Specs. Docking study was further carried out to refine the obtained hit compounds. Finally, a total of 28 compounds were selected based on the ranking order and visual examination, which were first evaluated by a cell line-based assay. Seven compounds that have good inhibition activity against two FAS overexpressing cancer cell lines were further evaluated by an enzyme-based assay. One compound with a new chemical scaffold was found to have low micromolar inhibition potency against FAS, which has been subjected to further chemical structural modification.

[Surface modification of RGD peptides onto acellularized porcine aortic valve to promote cell adhesion].

OBJECTIVE: To investigate the impact of RGD peptides on cell adhesion to acellularized procine aortic valve. METHODS: The acellular porcine aorta valve (APAV) was prepared by removing the cells and cellular components from porcine aortic valve using trypsin and hyposmosis TritonX-100. With the help of epoxy chloropropane (EC), the decelluarized valve scaffolds were immobilized with YGRGDSP peptide. MFBs were seeded onto four groups [acellularized value (AV) group, EC group, glutaraldehyde+EC (GE) group and EC+ RGD group or GE+RGD group] of coupled, coated and untreated decelluarized valve scaffolds. Ninhydrin reaction, cell count and fluorescent imaging test were employed to examine the efficiency of cell adhesion. RESULTS: More cells were attached to the decellularized valve scaffolds when the cells were coupled with RGD peptides compared with the others. The adhesive effect was correlated with the concentration of the RGD peptide and the attaching time. CONCLUSION: With the help of EC, YGRGDSP peptides can be immobilized by covalent bonding. RGD peptides improve cell adhesion to decellularized valve scaffolds.