Formation Of Spherical Particles Research Articles

Novel Nanoaggregates from Phoenix dactylifera (date palm) for Inhalational Management of Cystic Fibrosis Using Dry Powder Inhalers

PurposePhoenixdactylifera extracts have shown efficacy as antioxidants and antibacterials for the treatment of lung diseases; however, the choice of route of administration remains a problem. The use of natural antibacterial remedies for the management of cystic fibrosis (CF) is promising due to recurring bacterial resistance to current antibiotics. Dry powder inhalers (DPIs) have also been identified as a patient-friendly, noninvasive method for local delivery of drugs to the lungs. Therefore, this work, which is the first of its kind, aimed to formulate nanoparticles of date palm extracts as DPIs and evaluate their aerodynamic and antibacterial biofilm characteristics for the potential treatment of CF.MethodChitosan-based nanoparticles (CDN) comprising aqueous date fruit extract with increasing concentrations of chitosan (0.05, 0.1, and 0.2% w/v) were prepared. The in vitro aerosolization of the formulations was studied using a next-generation impactor (NGI), and good aerosolization profiles were achieved. The produced nanoparticles were characterized using FTIR and XRD to confirm physical properties and TEM and zeta sizer to confirm shape and size. The antimicrobial activity of CDN was evaluated using a Pseudomonas aeruginosa biofilm model cultured in an artificial sputum medium (ASM) mimicking cystic fibrosis conditions in the lungs.ResultsNanoparticles containing 0.05% w/v chitosan demonstrated the highest encapsulation efficiency (55.91%) and delivered the highest emitted dose (98.92%) and fine particle fraction (42.62%). CDN demonstrated the first-time-ever reported significant 3.3 log-cycle inhibition of P. aeruginosa biofilm cultured in ASM. TEM images revealed the formation of spherical particles with an average size of 42.98 ± 19.19 nm. FTIR and XRD studies demonstrated the compatibility of the components with the presence of the characteristic features of chitosan and date powder.ConclusionsThis novel work showcases CDN as a prophylactic adjuvant for the management of cystic fibrosis using DPI.

Tailoring hierarchical BiVO4 sub-micron particles for enhanced cyclability in asymmetric supercapacitor

This work demonstrates the feasibility of sub-micron size metal oxides as a sustainable charge storage material in supercapacitors fabrication and addressing the cycle instability issues of pseudocapacitors. The sub-micron bismuth vanadate (BiVO4) particles were synthesized by two different routes, co-precipitation (BVO-N) and sonochemical (BVO-S) methods. The morphological investigation of BVO-S showed hierarchical microspheres with diameter ranges of 1–6 μm, which is more prominent in size compared to BVO-N particles (100 nm- 1-μm in diameter). The nitric acid plays a crucial role in stabilizing the BiVO4 particles in the co-precipitation process, whereas ultrasonic waves predominantly control the spherical particle formation in the sonochemical route. The electrochemical performance of BVO-N and BVO-S was tested in a potassium hydroxide (KOH) electrolyte. The charge and discharge cycle experiments showed BVO-S microspheres are more highly stable than that BVO-N. The BVO-N starts to degrade with its initial capacitance beyond 1000 cycles. The poor stability of BVO-N may be due to the breakdown of surface-adsorbed charged ionic species. As a result, BVO-S performs with a higher specific capacitance value of 214 F/g compared to BVO-N (124 F/g). Trasatti analysis revealed a balanced, synergistic behaviour of pseudocapacitance (61 %) and electric double layer capacitance (39 %) at the BVO-S is responsible for their high specific capacitance compared to BVO-N. The BVO-S has low intrinsic resistance due to the highly denser micro-spherical structure, allowing electrolyte ions to access the inner and outer surfaces of the BVO-S. Interestingly, charge transfer resistance was decreased after the cyclic stability test due to electrochemical activation and facilitates fast ion transport increasing the surface contact area of active material at the electrode-electrolyte interface. We fabricate the asymmetric cell with BVO-S microspheres (anode), activated carbon particles (cathode) and Poly (ethylene oxide) (PEO) /Polyethene glycol dimethyl ether (PEGDME)/KOH gel-based electrolyte. This asymmetric supercapacitor performs with a specific capacitance value of 153 F/g at 0.3 A/g under the cell voltage of 1.2 V. Also, it delivers 30.6 Whkg−1 of energy density and 1983 W kg−1 of power density. The cyclic stability of 98 % over 5000 cycles was achieved in this configuration. This performance is appreciable compared to the previous work on BiVO4-based asymmetry supercapacitors, particularly a capacitance retention (%) and potential window. Overall, an acid-free sonochemical processing route reported in this work is highly environmentally friendly. Likewise, the sub-micron metal oxide particle significantly improves their electrochemical stability without the coalesced together with any carbonaceous material. It can be transferred to synthesizing a broader choice of metal oxide based for enhanced cyclability with effective utilization of their charge storage behaviour that will perform high-power storage, which powers short-distance electric transportation.

Evolution of an Electrochemically Inactive Metal–Organic Framework to Reticulated Porous Carbon Particles with High Supercapacitance

An iron-containing porphyrin-based porous metal–organic framework (PPMOF) has been synthesized and subsequently pyrolyzed to obtain the carbon structure with homogeneous distribution of nitrogen. The pyrolysis is carried out at different temperatures and in the presence of two different environments; in argon to obtain PPMOF-Ar-700, PPMOF-Ar-800, and PPMOF-Ar-900, and in nitrogen to obtain PPMOF-N-800. The motivation here is to study the change in the electrochemical properties that take place on conversion of the metal–organic framework to its corresponding carbons. The materials have been characterized by powder X-ray diffraction, nitrogen adsorption/desorption, scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy, among others. It was observed that PPMOF almost did not show any electrochemical response and was unstable, whereas the carbonized frameworks showed good supercapacitive behavior and stability. The surface area increases from 353 to 838 m2·g–1, when the pyrolysis gas is switched over from nitrogen to argon. It also results in the formation of uniform smooth spherical particles in PPMOF-Ar-800, in contrast to agglomerated broken particles in PPMOF-N-800. PPMOF-Ar-800 shows a remarkable specific capacitance value of 500 F·g–1 at a current density of 1 A·g–1 which is retained at a high value of 111 F·g–1 at a very high current density of 50 A·g–1 in galvanostatic charge/discharge studies, whereas for PPMOF-N-800, the specific capacitance is 400 F·g–1 at 1 A·g–1 and its discharge time is also shorter than that for PPMOF-Ar-800. This indicates that the pyrolysis environment plays a crucial role in the formation and stabilization of the carbon structures.

Effect of Ammonia on the Synthesis of NMC541 Cathode Materials with the Sol-Gel Method

The research studied about the effect of ammonia on the synthesis of lithium-ion battery cathode materials LiNi0.5Mn0.4Co0.1O2 (NMC541) through a sol-gel method by modifying the mole ratio of ammonia to metal forming ratios (0.5; 1.0; 1.5; and 2.0). The precipitation formed at pH 11 and at temperature of 80oC. Characterization was carried out on samples resulting from pyrolysis (pyrolysis result), with calcination for once and twice at 850oC for 3 hours, X-ray diffraction pattern characterization, morphological characterization using scanning electron microscope (SEM), and conductivity characterization using an impedance capacitance conductance (LCR) meter. The result of the synthesis is in the form of spherical particles. The addition of ammonia affected the particle size distribution and stoichiometry of the metal forming NMC541, eventhough it was not significant. The ammonia to metal ratio of 1.5 (Sample N1.5-K) resulted in the distribution with the optimum particle homogeneity. The morphology of the pyrolysis and 3 hours-850oC calcined samples was dominated by spherical particles and agglomeration. Particle growth in the material is affected by heat treatment time. Samples with ammonia to metal ratio of 2.0 (N2.0-K) have the closest stoichiometry to NMC541. The total conductivity of the sample at a measurement frequency of 42Hz-1MHz is in the value range of 10-7–10-5 S.cm-1. The particle size is also affected by the calcination temperature. The effect of using ammonia in the synthesis process is not directly related to the electrical properties. However, it is related to the purity of NMC541. Samples of N1.5-K pyrolyzed result and samples of N1.0-K (3 hour 850 oC calcined) have optimum conductivity values. Agglomeration as a calcination effect lowers the conductivity value. The addition of 3 hours of calcination time does not significantly increase the conductivity value

In Situ Reactive Formation of Mixed Oxides in Additively Manufactured Cobalt Alloy.

Oxide-dispersion-strengthened (ODS) alloys have long been considered for high temperature turbine, spacecraft, and nuclear reactor components due to their high temperature strength and radiation resistance. Conventional synthesis approaches of ODS alloys involve ball milling of powders and consolidation. In this work, a process-synergistic approach is used to introduce oxide particles during laser powder bed fusion (LPBF). Chromium (III) oxide (Cr2O3) powders are blended with a cobalt-based alloy, Mar-M 509, and exposed to laser irradiation, resulting in reduction-oxidation reactions involving metal (Ta, Ti, Zr) ions from the metal matrix to form mixed oxides of increased thermodynamic stability. A microstructure analysis indicates the formation of nanoscale spherical mixed oxide particles as well as large agglomerates with internal cracks. Chemical analyses confirm the presence of Ta, Ti, and Zr in agglomerated oxides, but primarily Zr in the nanoscale oxides. Mechanical testing reveals that agglomerate particle cracking is detrimental to tensile ductility compared to the base alloy, suggesting the need for improved processing methods to break up oxide particle clusters and promote their uniform dispersion during laser exposure.

SPRAY-DRIED CHITOSAN MICROSPHERES FOR SUSTAINED DELIVERY OF TRIFLUOPERAZINE HYDROCHLORIDE: FORMULATION AND IN VITRO EVALUATION

Objective: Sustained release systems have the potential to enhance the therapeutic responses in the long-term management of psychiatric disorders. In the present study, cross-linked microspheres of the antipsychotic drug Trifluoperazine (TFP) were prepared using biodegradable polymer-chitosan and various in vitro evaluations were performed on the prepared microspheres. Methods: The spray drying technique was used to prepare TFP-loaded chitosan microspheres. Tripolyphosphate (TPP) was incorporated into the chitosan solutions as a cross-linking agent in varying concentrations. Different evaluations like production yield, encapsulation efficiency, drug-polymer compatibility, Scanning Electron Microscopy (SEM), X-ray diffraction studies (XRD), Differential Scanning Colorimetry (DSC), particle size, zeta potential analysis and in vitro drug release studies were performed on the developed formulations. Results: The formulated microparticles exhibited production yields ranging from 38.51 to 57.21% and had reasonably good encapsulation efficiencies (54.52-78.35%). The drug excipient compatibility was confirmed by Infrared Spectroscopy. All the microspheres showed positive zeta potential with a mean diameter ranging from 1.45-3.61µ. SEM images revealed the formation of spherical particles with indentations on the surface. XRD and DSC studies confirmed the presence of an amorphous form of the drug inside the microspheres. The in vitro release profile of TFP from cross-linked chitosan microspheres was influenced considerably by changing the concentration of polymer and crosslinking agent in the formulation. The drug release from (0.5%) chitosan microspheres reduced from 91% to 79%, when TPP concentration was increased from 10% w/w to 30% w/w. All the formulations clearly showed a burst release of the drug in the initial hours and a subsequent sustained release profile. Conclusion: The results of this study suggest that TPP crosslinked spray-dried chitosan microparticles could be a promising method for developing a long-acting drug delivery system intended to effectively treat schizophrenia.

Spray-Drying Microencapsulation of Andean Blueberry (Vaccinium meridionale Sw.) Anthocyanins Using Prickly Pear (Opuntia ficus indica L.) Peel Mucilage or Gum Arabic: A Comparative Study.

The recovery of byproducts from the food industry is a promising approach to obtain hydrophilic biopolymers with potential health benefits. In this work, the mucilage obtained from the peel of the Opuntia ficus-indica (OFI) fruit was compared with gum arabic (GA) as wall materials for the microencapsulation of Colombian blueberry anthocyanins, using the spray-drying process. For both types of microencapsulates, the following were determined: anthocyanin content (UV-vis and HPLC/MS-MS), total dietary content (enzymatic-gravimetric method), antioxidant activity (ORAC), color (CIELab parameters), morphology (SEM and particle size), and thermal behavior (DSC/TGA). Six different anthocyanins were identified by HPLC/MS-MS in the non-lyophilized Andean blueberry sample (LABP) and in the OFI-mucilage and GA microcapsules. OFI mucilage, compared to GA, favors the formation of larger spherical particles, a smoother surface without cracks, and greater thermal stability. The higher anthocyanin retention capacity in OFI microcapsules leads to higher antioxidant capacity and red coloration for this biomaterial. Consequently, the microencapsulation of anthocyanins with mucilage from the peel of the OFI fruit is proposed as a promising alternative for the protection and incorporation of this natural dye with high antioxidant capacity and dietary fiber content in new functional food/cosmetic formulations, while giving added value to the natural byproducts of OFI.

Microstructure, thermostability and tribological behavior of composite CoCrFeNiTix high-entropy alloy coatings fabricated by laser cladding

CoCrFeNiTix (x = 0,0.25,0.5,0.75,1.0) high-entropy alloy (HEA) coatings were prepared on 45 steel by laser cladding, to explore the microstructural evolution, thermostability and the high-temperature tribological behavior of the coating. Ti-doping promotes more intergranular hard BCC phase and TiO2 intermetallics to precipitate from the ductile matrix of FCC phase, resulting in an increase in the averaged microhardness. The favorable thermostability of the heterogeneous microstructure and the oxide layer induced by friction endow the laser cladded HEA coating with excellent dry sliding wear-resistance in a wide temperature range from room temperature to 800 °C. Taking the place of the adhesive wear at room temperature, the oxidative wear becomes dominant in the wear process when the temperature exceeds 200 °C, contributing to the decrease in the wear rate before 600 °C. The formation of spherical particles on the wear track, as well as the oxide layer at elevated temperature, are revealed from the perspective of thermodynamic. It is found that the protective oxide layer is susceptive to delaminate due to the synergetic effect of strength reduction, internal stress accumulation and the destruction of the bonding, which explains the rise of the wear rate from its lower value of 1.84 × 10−5 mm3/(N·m) at 600 °C to 9.64 × 10−5 mm3/(N·m) at 800 °C.

In situ formation of spherical MoS2 particles on high-entropy alloy coating for low friction

Introductionof lubricant phase into thermally sprayed coating while avoids high-temperature ablation is still a challenge. Here, vacuum impregnation and hydrothermal reaction, acted as a post-treatment process, was applied to synthesize MoS2 phase on and within high-entropy alloy (HEA) coating. The as-synthesized MoS2 phase with high purity and spherical shape distributed in the pores and finally formed a thin layer on coating surface. Compared to the single HEA coating, coefficient of friction (COF) and wear rate (Q) of the HEA/MoS2 composite coatings possessed a significantly reduction, i.e 87.2% and 75.6% reduction in COF and Q at 2 N, respectively. Besides, owing to the formation of lubricating film during the sliding process, the composite coating had a more stable sliding process. At the same time, the doped MoS2 played a positive role in reducing abrasive- and adhesive wears for both coating and coupling ball. Since the lubricating film can be continuously replenished and repaired, the HEA/MoS2 self-lubricating coatings maintained a good chemical stability and provided a relatively good wear properties.

Sprayed FeWO4 thin film-based memristive device with negative differential resistance effect for non-volatile memory and synaptic learning applications

Resistive switching (RS) memories have attracted great attention as promising solutions to next-generation non-volatile memories and computing technologies because of their simple device configuration, high on/off ratio, low power consumption, fast switching, long retention, and significant cyclic stability. In this work, uniform and adherent iron tungstate (FeWO4) thin films were synthesized by the spray pyrolysis method with various precursor solution volumes, and these were tested as a switching layer for the fabrication of Ag/FWO/FTO memristive devices. The detailed structural investigation was done through various analytical and physio-chemical characterizations viz. X-ray diffraction (XRD) and its Rietveld refinement, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) techniques. The results reveal the pure and single-phase FeWO4 compound thin film formation. Surface morphological study shows the spherical particle formation having a diameter in the range of 20 to 40 nm. The RS characteristics of the Ag/FWO/FTO memristive device demonstrate non-volatile memory characteristics with significant endurance and retention properties. Interestingly, the memory devices show stable and reproducible negative differential resistance (NDR) effects. The in-depth statistical analysis suggests the good operational uniformity of the device. Moreover, the switching voltages of the Ag/FWO/FTO memristive device were modeled using the time series analysis technique by utilizing Holt’s Winter Exponential Smoothing (HWES) approach. Additionally, the device mimics bio-synaptic properties such as potentiation/depression, excitatory post-synaptic current (EPSC), and spike-timing-dependent plasticity (STDP) learning rules. For the present device, the space-charge-limited current (SCLC) and trap-controlled-SCLC effects dominated during positive and negative bias I–V characteristics, respectively. The RS mechanism dominated in the low resistance state (LRS), and the high resistance state (HRS) was explained based on the formation and rupture of conductive filament composed of Ag ions and oxygen vacancies. This work demonstrates the RS in the metal tungstate-based memristive devices and demonstrates a low-cost approach for fabricating memristive devices.

Synthesis and Characterization of Sol–Gel‐Derived SiO2–CaO Particles: Size Impact on Glass (Bio)Properties

AbstractFour highly bioactive glasses in a binary SiO2–CaO system are prepared following a sol−gel method using Ca(OH)2 as a calcium precursor. In the synthesis of glass according to the modified Stöber method, Ca(OH)2 suspended in polyethylene glycol allows the elimination of the presence of calcite and the increase of ammonia concentration causes formation of spherical particles with different sizes in the range of 26–266 nm. The relation among the size and properties, including bioactivity, of the glass particles is evaluated. New glasses that vary in composition (10–25 wt% CaO), porosity (15–113 m2 g−1), and hydroxyl groups content greatly enhance the formation process of hydroxyapatite (HA) in simulated physiological fluids. For all glasses, superior apatite‐mineralization ability in time as short as 2 h in the physiological‐like buffer is achieved, thus exceeding the bioactivity of the known bioactive glasses, including 45S5 glass (Bioglass). The assessment of the safety and toxicity profile of the obtained glasses is verified in a wide range of concentrations (1–1000 µg mL−1) against human dermal fibroblasts and MC3T3 mouse osteoblast precursors, but also to human erythrocytes by determining hemocompatibility. Two glasses of different sizes, 73 and 266 nm, are promising and warrant further research.

Of fiery sparks and glittering spots: melting-resolidification and spherical particle formation in abrasion

The curious occurrence of perfectly spherical particle debris when a steel substrate is slid against a hard abrasive was first documented by Robert Hooke in the seventeenth century. Similar observations now abound in other abrasion-type processes, from industrial grinding to sliding rock faults. The prevalent hypothesis, originally proposed by Hooke, is that these particles form due to high local temperatures, resulting in particle ejection, melting and resolidification. In this work, we revisit this hypothesis, using a model steel-abrasive contact, a combination ofin situand post-process investigations, and complementary analytical calculations. Our results reveal two primary findings—firstly, the temperature of particles ejected from the contact zone is far from the melting point, and secondly, exothermic surface oxidation plays a critical role in actually melting the particle. Melting is either complete or partial, leading to spherical particles or ‘slivers’, as described originally by Hooke. Finally, we confirm that resulting particle surface patterns are typical of rapid solidification from the melt. Apart from throwing light on a centuries’ old curiosity, our results precisely quantify the melting-resolidification process, with implications for a variety of applications, ranging from abrasion and powder production to the formation of micrometeorite dust.

Enhanced Pharmacokinetics and Anti-inflammatory Activity of Curcumin Using Dry Emulsion as Drug Delivery Vehicle.

Many naturally available dietary molecules such as curcumin have not seen the market due to poor solubility, bioavailability, and photodegradability. Successful development of a lipid-based dry emulsion may overcome these issues and help in reaching the markets for natural dietary molecules such as curcumin. The current study aims to develop a dry emulsion formulation of curcumin using natural oil and evaluate its dissolution, photostability, pharmacokinetics, and anti-inflammatory activity. Dry emulsions were prepared using emu oil and corn oil as the lipid phase, Caproyl 90 and Cremophor RH 40 as surfactants, and dextrin as a hydrophilic carrier. Microscopic studies showed the formation of spherical porous particles, and solid-state characterization using differential scanning calorimetry and powder X-ray diffraction showed the conversion of curcumin to an amorphous form. About 80% drug release was observed from formulation, whereas pure drug showed only 50% drug release in 30min. Invivo pharmacokinetic studies showed fivefold improvement in the maximum concentration of curcumin in plasma (Cmax) and sevenfold improvement in the area under the concentration-timecurve of curcumin from emu oil formulation compared with pure curcumin. Significant differences were observed in the anti-inflammatory activity of curcumin dry emulsion and plain curcumin. Emu-oil-based formulations showed synergistic anti-inflammatory activity over corn-oil-based formulations with improved photostability. The present study suggests that the dry emulsion may enhance the bioavailability with synergistic anti-inflammatory activity and photostability of curcumin when given orally.

Synthesis of Graphite-Encapsulated Ni Micro- and Nanoparticles Using Liquid-Phase Arc Discharge

In this work, the synthesis of nickel particles encapsulated in a few-layer graphene shell was carried out using the method of electric arc discharge in the liquid phase, in various media: deionized water, alcohol, and toluene. Nickel and graphite were used as electrodes. The study was carried out to analyze how various liquids, acting as a cooling medium and a source of carbon, affect the formation of a protective shell around metal particles. Raman studies, analysis of X-ray diffraction data, and scanning electron microscopy confirmed the formation of spherical encapsulated nickel particles in all types of liquid media. It was found out that the use of toluene as a cooling medium increased the number of particles with a graphite shell and allowed obtaining micro- and nanoparticles covered with monolayer graphene. The absence of oxygen in the composition of toluene, in contrast with alcohol and especially water, prevents the oxidation of nickel particles during the synthesis. This fact, along with the initial basic hexagonal carbon structure of toluene, makes it a good medium for the formation of metal particles covered with a protecting graphite shell as a result of arc discharge in the liquid phase.

Anion-assisted supramolecular polymerization of luminescent organic π-conjugated chromophores in a moderately polar solvent: tunable nanostructures and their corresponding effects on electronic properties.

Supramolecular polymers of π-conjugated organic chromophores have emerged as promising candidates in organic electronics because of their dynamic and highly ordered molecular organization. Herein, we demonstrate the formation of luminescent, highly conducting supramolecular polymers of a functionalized naphthalimide π-chromophore-based organic semiconductor in a moderately polar organic solvent (tetrahydrofuran) by overcoming solute-solvent H-bonding via assistance from fluoride anions. The polymerization is exclusively guided by the synergistic effects of cascade H-bonding (F-⋯H-N- of primary amines, followed by -CO⋯H-N- of amides), π-π stacking and hydrophobic interactions. An increasing molar equivalent of anions leads to a morphology transition from 1D nanowires to 2D nanosheets via nanotubes and nanorings, but above a particular threshold of the same anion, depolymerization-mediated disruption of long-range order and formation of non-luminescent spherical particles was observed. Such significant impacts of anions in supramolecular polymerization-depolymerization were utilized in modulating the electronic properties of this naphthalimide-based organic semiconductor.

Antigenicity and immunogenicity of chikungunya virus-like particles from mosquito cells.

The spread of chikungunya virus (CHIKV) is reaching pandemic levels, and vaccines and antivirals to control CHIKV infection have yet to be approved. Virus-like particles (VLPs), a self-assembled native multi-subunit protein structure, could potentially be used as an antigen for serological detection and vaccine development. In the current study, we describe the production of novel CHIKV VLPs from mosquitoes using a Baculovirus/Mosquito (BacMos) system in a simple Biosafety Level-2 laboratory. Substantial envelope and capsid protein secretions were detected in culture medium. Co-fractionation of CHIKV E2, E1, and capsid proteins via sucrose gradient ultracentrifugation provided evidence of VLP formation. Transmission electron microscopy and dynamic light scattering analysis revealed the formation of VLPs in the form of spherical particles with a diameter of roughly 40nm in transduced cells and culture medium. VLP-based IgM capture ELISA in CHIKV patient sera revealed native epitopes on the VLPs. These non-purified VLPs were shown to act as an antigen in CHIKV-specific IgM capture ELISA. The immunization of CHIKV-VLPs alone in mice induced a balance CHIKV-specific IgG2a/IgG1 antibodies and neutralized antibody responses. The study provides support for the hypothesis that mosquito cell-derived CHIKV VLPs could serve as a novel antigen for serological detection and the development of vaccines against CHIKV infection. KEY POINTS: • CHIKV VLPs secreted from BacMos-CHIKV 26S-transduced mosquito cell. • This CHIKV VLPs potentially serve as an alternative capture antigen for MAC-ELISA. • Unadjuvanted CHIK VLPs induce CHIKV-specific IgG and NT responses in mice.

Microwave-assisted biosynthesis of ZnO-GO particles using orange peel extract for photocatalytic degradation of methylene blue

In this study, ZnO-GO particles for the photocatalytic degradation of methylene blue (MB) dye were successfully biosynthesized. Microwave-assisted biosynthesis was carried out using the extract of orange peel powder, ethylene glycol, and water as solvents. In addition to the formation of spherical ZnO particles, the phytochemicals present in the extract promoted the impregnation of organic compounds that were transformed into graphene oxide due to the annealing process. The effect of the amount of zinc source and the annealing temperature on the variation of the obtained powder structural, optical, morphological, superficial, and photocatalytic properties was studied by XRD, FE-SEM, TEM, XPS, BET, Raman, and UV–vis spectroscopy. Reducing the amount of zinc source and increasing the annealing temperature promoted the reduction of deformation and structural defects (measured as Urbach energy) and increased the superficial area available which improved the photocatalytic performance. On the other hand, it was observed that graphene oxide increased the adsorption of the dye thus improving its removal efficiency. The effect of the catalyst dosage and the pH of the dye solution were also tested, finding the best performance with 75 mg and a pH of 12, with an efficiency of 100% during 90 min of illumination under UV light (55 W). The kinetic study showed to follow a pseudo-first-order for all cases. Also, the stability of the catalyst was tested for 8 cycles, achieving at least 80% removal. Trapping experiments showed that hydroxyl radicals and holes are the more important chemical reactive species in the degradation mechanism of MB. Finally, our synthesized catalyst showed similar photocatalytic performance compared to high-purity commercial TiO2 and ZnO.

Stage-specific and location-specific cartilage calcification in osteoarthritis development

ObjectivesThis study investigated the stage-specific and location-specific deposition and characteristics of minerals in human osteoarthritis (OA) cartilages via multiple nano-analytical technologies.MethodsNormal and OA cartilages were serially sectioned for micro-CT, scanning...

Controlling the Morphology of Electrodeposited Lithium Metal Via Seeded Growth: Stepwise Spherial to Fibrous Lithium Growth

Lithium metal has been gained intense research interest because of its high specific capacity and lowest electrochemical potential for next generation battery systems with high energy density. However, the utilization of Li metal as an anode material has been limited due to the uncontrolled Li deposition and side reactions on Li metal surface that induce low coulombic efficiency, poor cycle performance and safety issues. Controlling morphology of electrodeposited Li metal is one major direction to resolve these issues. Identification of Li deposition mechanism governing the morphology evolution is prerequisite for establishing strategy for controlling morphology. Herein, we explore governing deposition mechanism from the morphology evolution at varied current (0.2- 1.8 mA cm-2) and suggest a strategy for growing low surface area Li fibers.We found that fibrous Li growth follows the initial spherical Li particle formation when the Li sphere size reaches the critical value. The diameter of the initially formed Li particles decreases with the current density. Initially formed spherical Li particles at a low current density (0.2 mA cm-2) are sufficiently large to grow with a fibrous morphology. Thus, the spherical particles evolve to fibrous Li during subsequent growth. On the other hand, at a higher current density, the Li particles are initially smaller than the critical size and thus cannot immediately grow into a fibrous morphology. Spherical growth of the existing Li particles and additional nucleation on the current collector surface continue, resulting in multilayer Li particles. After Li particles reach the critical size, Li can grow with a fibrous form. Due to the preferential deposition on the existing fibrous Li, the morphology of spherical Li particles smaller than the critical size does not change. Therefore, only fibrous Li deposits were formed at low current density (0.2 mA cm-2), but both spherical and fibrous Li deposits were formed at higher current densities.Based on the morphology evolution mechanism, seeded Li deposition strategy was proposed to minimize the surface area of Li deposits and improve cycling stability of Li metal electrode. The stepwise spherical to fibrous Li growth was achieved by changing the current from low to high (0.2 to 1.8 mA cm-2). Li deposits morphology was well controlled by this strategy resulting in all fibrous morphology with smooth surface. The Li deposits of seeded growth strategy achieved smaller surface area, suppressed side reactions and improved cycle life more than four times compared to that of constant current deposition with same average current density (1 mA cm-2). Figure 1

Functional Nanogel from Natural Substances for Delivery of Doxorubicin

Nanogels (NGs) have attracted great attention because of their outstanding biocompatibility, biodegradability, very low toxicity, flexibility, and softness. NGs are characterized with a low and nonspecific interaction with blood proteins, meaning that they do not induce any immunological responses in the body. Due to these properties, NGs are considered promising candidates for pharmaceutical and biomedical application. In this work, we introduce the development of novel functional nanogel obtained from two naturally based products—citric acid (CA) and pentane-1,2,5-triol (PT). The nanogel was synthesized by precipitation esterification reaction of CA and PT in tetrahydrofuran using N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide (EDC) and 4-(dimethylamino)pyridine (DMAP) catalyst system. Dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM) and atomic force microscopy (AFM) analyses revealed formation of spherical nanogel particles with a negative surface charge. Next, the nanogel was loaded with doxorubicin hydrochloride (DOX) by electrostatic interactions between carboxylic groups present in the nanogel and amino groups of DOX. The drug-loaded nanogel exhibited high encapsulation efficiency (EE~95%), and a bi-phasic release behavior. Embedding DOX into nanogel also stabilized the drug against photodegradation. The degradability of nanogel under acidic and neutral conditions with time was investigated as well.