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Novel Strain Engineering Combined with a Microscopic Pore Synergistic Modulated Strategy for Designing Lattice Tensile-Strained Porous V2C-MXene for High-Performance Overall Water Splitting

Yu Zhou, Yousen Wu, Dongxuan Guo, Jinlong Li, Yue Li, Xue Yang, Shanshan Fu, Guozhe Sui, Dong-Feng Chai

Abstract

Transition metal carbon/nitride (MXene) holds immense potential as an innovative electrocatalyst for enhancing the overall water splitting properties. Nevertheless, the re-stacking nature induced by van der Waals force remains a significant challenge. In this work, the lattice tensile-strained porous V2C-MXene (named as TS(24)-P(50)-V2C) is successfully constructed via the rapid spray freezing method and the following hydrothermal treatment. Besides, the influence of lattice strain degree and microscopic pores on the catalytic ability is reviewed and explored systematically. The lattice tensile strain within V2C-MXene could widen the interlayer spacing and accelerate the ion transfer. The microscopic pores could change the ion transmission path and shorten the migration distance. As a consequence, the obtained TS(24)-P(50)-V2C shows extraordinary hydrogen evolution reaction and oxygen evolution reaction activity with the overpotential of 154 and 269 mV, respectively, at the current density of 10 mA/cm2, which is quite remarkable compared to the MXene-based electrocatalysts. Moreover, the overall water splitting device assembled using TS(24)-P(50)-V2C as both anode and cathode demonstrates a low cell voltage requirement of 1.57 V to obtain 10 mA/cm2. Overall, the implementation of this work could offer an exciting avenue to overcome the re-stacking issue of V2C-MXene, affording a high-efficiency electrocatalyst with superior catalytic activity and desirable reaction kinetics.

Keywords

lattice strain, microscopic pores, V2C-MXene, re-stack, overall water splitting

A review of chemical looping combustion technology: Fundamentals, and development of natural, industrial waste, and synthetic oxygen carriers

Sanaz Daneshmand-Jahromi, Mohammad Hashem Sedghkerdar, Nader Mahinpey

Abstract

This review aims to give a detailed knowledge of the selection and fabrication methods of oxygen carrier (OC) materials for the Chemical Looping Combustion (CLC) reporting up to 2022. The CLC process is a well-known chemical technology for capturing CO2 emissions with the generation of energy. In this process, OCs are utilized as a medium for oxygen transportation between fuel and air reactors. The main challenge in scaling up the CLC process is the development of appropriate OCs with optimal properties, including high transport oxygen capacity, reactivity, and stability. This review compiles the fundamentals of the CLC process using gaseous fuel, the kinetics of the reduction and oxidation reactions, and extensive studies on the fabrication of OC materials. In addition to the natural ore and industrial waste OCs, this paper extensively discussed the synthesized OCs. The synthetic OCs are classified based on the preparation methods including mechanical mixing, sol–gel, co-precipitation, impregnation, freeze granulation, and spray-drying. For each study, the active phase, support material, operating condition, and key findings are reported. Finally, the different lab- and pilot-scales operating facilities are summarized.

Keywords

Chemical looping combustion, Carbon capture, Natural/industrial waste oxygen carriers, Synthetic oxygen carrier, Preparation methods, Pilot plants

Combination of α-lactalbumin and gum arabic for microencapsulation of L-menthol: The effects on flavor release during storage and rehydration

Siyi Peng, Jiajia Zhao, Yaru Wang, Fang Chen, Xiaosong Hu, Lingjun Ma, Junfu Ji

Abstract

L-menthol-containing food products generally show the flavor loss during storage due to their high volatility. The hydrophobicity of L-menthol also causes the inadequate flavor release during rehydration. In this study, the stability of L-menthol was enhanced by microencapsulation and the effect of different powder drying techniques was also investigated. The highest efficiency (76.58–78.66 %) and loading content (18.58–28.35 mg/g) of encapsulations were obtained by using a mass ratio of 2:1(α-LA: GA). Then they were dried by non-thermal spray freeze drying (SFD) technique compared to spray drying (SD) and freeze-drying (FD) process. The SFD particles were shown to be spherical and porous with the highest porosity (86.82 %). α-LA/GA based microparticles with spherical shapes were demonstrated to largely enhance flavor retention during high humidity storage. In addition, the porous structures of SFD powders could cause rapid rehydration in liquid models, and the release behaviors of loaded L-menthol followed the Fickian diffusion. Consequently, the SFD technique shows great potential to produce microparticles by regulating the release behaviors of L-menthol during storage and rehydration.

Keywords

Spray freeze drying, Protein-polysaccharide complex, Powder microparticle, Flavor retention, Release kinetics

Inhalable aerosol microparticles with low carrier dosage and high fine particle fraction prepared by spray-freeze-drying

Quan Xi, Jiaying Miao, Zhen Cao, Hao Wang

Abstract

Co-suspension drug-loading technology, namely Aerosphere™, can improve fine particle fraction (FPF) and delivered dose content uniformity (DDCU). However, because of its poor drug-loading efficacy, the phospholipid carrier dosage in Aerosphere™ is usually dozens of times greater than that of the drug, resulting in a high material cost and blockage of the actuator. In this study, spray-freeze-drying (SFD) technology was used to prepare inhalable distearoylphosphatidylcholine (DSPC)-based microparticles for pressurized metered-dose inhalers (pMDI). Water-soluble, low-dose formoterol fumarate was used as an indicator to evaluate the aerodynamic performance of the inhalable microparticles. Water-insoluble, high-dose mometasone furoate was used to investigate the effects of drug morphology and drug-loading mode on the drug delivery efficiency of the microparticles. The results demonstrated that DSPC-based microparticles prepared using the co-SFD technology not only achieved higher FPF and more consistent delivered dose than those of drug crystal-only pMDI, but the amount of DSPC was also reduced to approximately 4% of that prepared using the co-suspension technology. This SFD technology may also be used to improve the drug delivery efficiency of other water-insoluble and high-dose drugs.

Keywords

Aerodynamic performance; Delivered dose content uniformity; Drug-loading method; Inhalable microparticles; Pressurized metered dose inhaler; Spray-freeze-drying.

Aquivion® PFSA-based spray-freeze dried composite materials with SiO2 and TiO2 as hybrid catalysts for the gas phase dehydration of ethanol to ethylene in mild conditions

Stefania Albonetti, Martina Battisti, Sara Andreaoli, Riccardo Bacile, Claudio Oldani, Simona Ortelli, Anna Luisa Costa, Giuseppe Fornasari

Abstract

The spray-freeze-drying approach was successfully applied for the preparation of Aquivion based composites with high surface area. The encapsulation of different oxides, such as TiO 2 and SiO 2 in the superacid matrix was easily obtained using this technique and compared with catalysts prepared by the impregnation conventional route. SFD approach led to the preparation of porous micro-granules characterised by a high homogeneity in the phase distribution. The prepared materials were active and selective for the gas phase dehydration of ethanol to ethylene in mild conditions. The increase of the accessibility and the stability of active sites improved the activity of the composites and allowed to reduce the amount of the superacid resin. Moreover, the type of encapsulated oxide, TiO 2 or SiO 2 , modified the improved performance of the catalysts , having TiO2 the higher efficiency for ethanol conversion and selectivity in ethylene at very low temperature.

Keywords

heterogeneous acid catalysts, perfluorosulfonic resins, ethanol dehydration, ethylene

Effect of different drying methods on the functional properties of probiotics encapsulated using prebiotic substances

K. S. Yoha, J. A. Moses, C. Anandharamakrishnan

Abstract

Probiotics and prebiotics together work synergistically as synbiotics and confer various health benefits. Many studies on synbiotic foods only focus on the survival of probiotics but fail to evaluate their functional properties. The impact on functional properties should be explored to better understand its therapeutic efficacy. In this work, probiotics (Lactiplantibacillus plantarum NCIM 2083) were encapsulated with prebiotics (fructooligosaccharide + whey protein + maltodextrin) using spray-drying (SD), freeze-drying (FD), spray-freeze-drying (SFD), and refractance window-drying (RWD) techniques. Aggregation, intestinal adhesion, antagonistic activity, and bile salt hydrolase (BSH) activity of probiotics were studied before and after the encapsulation process. The SFD probiotics showed better aggregation ability (79% at 24-h incubation), on par with free cells (FC) (81% at 24-h incubation). The co-aggregation ability of encapsulated probiotics has drastic variations with each pathogenic strain. The adhesion ability of probiotics in chicken intestinal mucus was assessed by the crystal violet method, indicating no significant variations between FC and SFD probiotics. Also, encapsulated probiotics exhibit antagonistic activity (zone of inhibition in mm) against gut pathogens E. coli (11.33 to 17.34), S. faecalis (8.83 to 15.32), L. monocytogenes (13.67 to 18), S. boydii (12.17 to 15.5), and S. typhi (2.17 to 6.86). Overall, these studies confirm the significance and impact of various drying techniques on the functionality of encapsulated probiotics in synbiotic powders.

Recent progress in drying technologies for improving the stability and delivery efficiency of biopharmaceuticals

Fakhrossadat Emami, Mahsa Keihan Shokooh, Seyed Jamaleddin Mostafavi Yazdi

Abstract

Background: Most biopharmaceuticals are developed in liquid dosage forms that are less stable than solid forms. To ensure the stability of biopharmaceuticals, it is critical to use an effective drying technique in the presence of an appropriate stabilizing excipient. Various drying techniques are available for this purpose, such as freeze drying or lyophilization, spray drying, spray freeze-drying, supercritical fluid drying, particle replication in nonwetting templates, and fluidized bed drying.

Area covered: In this review, we discuss drying technologies and their applications in the production of stable solid-state biopharmaceuticals, providing examples of commercially available products or clinical trial formulations. Alongside this, we also review how different analytical methods may be utilized in the evaluation of aerosol performance and powder characteristics of dried protein powders. Finally, we assess the protein integrity in terms of conformational and physicochemical stability and biological activity.

Expert opinion: With the aim of treating either infectious respiratory diseases or systemic disorders, inhaled biopharmaceuticals reduce both therapeutic dose and cost of therapy. Drying methods in the presence of optimized protein/stabilizer combinations, produce solid dosage forms of proteins with greater stability. A suitable drying method was chosen, and the process parameters were optimized based on the route of protein administration. With the ongoing trend of addressing deficiencies in biopharmaceutical production, developing new methods to replace conventional drying methods, and investigating novel excipients for more efficient stabilizing effects, these products have the potential to dominate the pharmaceutical industry in the future.

Keywords

Biopharmaceuticals, Characterization, Drying, Solid-dosage form, Stability.

Spray freeze dried niclosamide nanocrystals embedded dry powder for high dose pulmonary delivery

Shengyu Zhang, Shen Yan, Kangwei Lu, Shixuan Qiu, Xiao Dong Chen, Winston Duo Wu

Abstract

Based on the drug repositioning strategy, niclosamide (NCL) has shown potential applications for treating COVID-19. However, the development of new formulations for effective NCL delivery is still challenging. Herein, NCL-embedded dry powder for inhalation (NeDPI) was fabricated by a novel spray freeze drying technology. The addition of Tween-80 together with 1,2-Distearoyl-sn-glycero-3-phosphocholine showed the synergistic effects on improving both the dispersibility of primary NCL nanocrystals suspended in the feed liquid and the spherical structure integrity of the spray freeze dried (SFD) microparticle. The SFD microparticle size, morphology, crystal properties, flowability and aerosol performance were systematically investigated by regulating the feed liquid composition and freezing temperature. The addition of leucine as the aerosol enhancer promoted the microparticle sphericity with greatly improved flowability. The optimal sample (SF_{– 80}D-N₂₀L₂D₂T₁) showed the highest fine particle fraction of ∼47.83%, equivalently over 3.8 mg NCL that could reach the deep lung when inhaling 10 mg dry powders.

Keywords

Fine particle fraction, NCL-embedded dry powder for inhalation (NeDPI), Particle formation mechanism, Spray freeze drying, Structure-performance relationship

Crystal Size Dependence of the Photo-Electrochemical Water Oxidation on Nanoparticulate CaTiO3

Monika Klusáčková, Roman Nebel, Kateřina Minhová Macounová, Petr Krtil

Abstract

Nanocrystalline CaTiO₃ materials with controlled particle size were prepared using spray-freezing/freeze-drying approach utilizing gelatine as a structure-directing agent. The resulting materials show characteristic particle size between 19 and 60 nm. The shape of the nanocrystals changes from cube-like single crystal containing particles into less regular isometric particles. Prepared materials as identified by X-ray diffraction analysis are formed by orthorhombic perovskite with small admixture of cubic phase. The ratio of both perovskite phases is independent of the particle size or prevailing crystal shape. All prepared materials show n-semiconducting character with band gap of ca 3.6 eV. They also show photo-electrochemical activity in water oxidation in acid media if a bias greater than 400 mV with respect to the flat band potential is applied. The specific photo-electrochemical activity decreases with increasing specific surface area. This behavior is attributed to increased probability of the electron transfer at the illuminated CaTiO₃ surface facilitated by the surface states. The CaTiO₃ materials also generate significant amount of ozone upon illumination in oxygen saturated solutions. The tendency to form ozone increases with increasing particle size suggesting that the ozone formation is hindered on materials with large number of low dimensionality states (crystal edges and vertices).

Keywords

Calcium titanate, Photo-electrochemistry, Water oxidation, Ozone formation, Spray-freezing/freeze-drying synthesis

Spray Freeze Drying of Biologics: A Review and Applications for Inhalation Delivery

Susana Farinha, João V. Sá, Paulo Roque Lino, Marco Galésio, João Pires, Miguel Ângelo Rodrigues, João Henriques

Abstract

Biopharmaceuticals have established an indisputable presence in the pharmaceutical pipeline, enabling highly specific new therapies. However, manufacturing, isolating, and delivering these highly complex molecules to patients present multiple challenges, including the short shelf-life of biologically derived products. Administration of biopharmaceuticals through inhalation has been gaining attention as an alternative to overcome the burdens associated with intravenous administration. Although most of the inhaled biopharmaceuticals in clinical trials are being administered through nebulization, dry powder inhalers (DPIs) are considered a viable alternative to liquid solutions due to enhanced stability. While freeze drying (FD) and spray drying (SD) are currently seen as the most viable solutions for drying biopharmaceuticals, spray freeze drying (SFD) has recently started gaining attention as an alternative to these technologies as it enables unique powder properties which favor this family of drug products. The present review focus on the application of SFD to produce dry powders of biopharmaceuticals, with special focus on inhalation delivery. Thus, it provides an overview of the critical quality attributes (CQAs) of these dry powders. Then, a detailed explanation of the SFD fundamental principles as well as the different existing variants is presented, together with a discussion regarding the opportunities and challenges of SFD as an enabling technology for inhalation-based biopharmaceuticals. Finally, a review of the main formulation strategies and their impact on the stability and performance of inhalable biopharmaceuticals produced via SDF is performed. Overall, this review presents a comprehensive assessment of the current and future applications of SFD in biopharmaceuticals for inhalation delivery.

Keywords

biopharmaceuticals, formulation, inhalation delivery, particle engineering, spray freeze drying