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Microfluidic flow reactors functionalized with immobilized human liver microsomes (HLM chips) represent a powerful tool for drug discovery and development by enabling mechanism-based enzyme inhibition studies under flow-through conditions. Additionally, HLM chips may be exploited in streamlined production of human drug metabolites for subsequent microfluidic in vitro organ models or as metabolite standards for drug safety assessment. However, the limited shelf life of the biofunctionalized microreactors generally poses a major barrier to their commercial adaptation in terms of both storage and shipping. The shelf life of the HLM chips in the wetted state is ca. 2-3 weeks only and requires cold storage at 4 °C. In this study, we developed a freeze-drying method for lyophilization of HLMs that are readily immobilized inside microfluidic pillar arrays made from off-stoichiometric thiol-ene polymer. The success of lyophilization was evaluated by monitoring the cytochrome P450 and UDP-glucuronosyltransferase enzyme activities of rehydrated HLMs for several months post-freeze-drying. By adapting the freeze-drying protocol, the HLM chips could be stored at room temperature (protected from light and moisture) for at least 9 months ( n = 2 independent batches) and up to 16 months at best, with recovered enzyme activities within 60-120% of the non-freeze-dried control chips. This is a major improvement over the cold-storage requirement and the limited shelf life of the non-freeze-dried HLM chips, which can significantly ease the design of experiments, decrease energy consumption during storage, and reduce the shipping costs with a view to commercial adaptation.

A controllable drying process and optimized drying parameters offer an indispensable role in the improvement of the quality and performance of propellant products. However, thus far, the influence of the relative humidity of hot-air on propellants has not been studied. In this study, the influence of relative humidity on drying characteristics of a double-base propellant is investigated for the first time, and the effect of relative humidity on the pore structure and thermal and mechanical properties of the propellant is comprehensively explored. The drying characteristic curve demonstrated that the drying of the propellant belongs to deceleration drying and is controlled by internal diffusion. Five semi-empirical kinetic models were employed to analyze the experimental data, and the results illustrate that the modified Midilli model can well describe the drying behavior of the propellant. The effective diffusion coefficient of volatile matter was calculated using the Fourier number method, the curve of diffusion coefficient varying with the ratio of volatile matter during drying was obtained, and the average effective diffusion coefficient was calculated. The results suggest that high relative humidity is beneficial to improve the drying efficiency of the propellant. The effect of relative humidity on the drying and heat transfer process of the propellant was also studied, and the mechanism of the effect of moisture on the drying rate of the propellant was further analyzed through molecular dynamics simulation. Additionally, the pore structure of the dried propellant was studied via mercury intrusion porosimetry and nitrogen desorption measurements, which indicated that relative humidity has a slight effect on pore size distribution, while the sample density of the propellant obtained at 80% relative humidity was significantly lower than that obtained at 40% and 60% relative humidity. The thermal stability of the samples was studied via DSC and TG analysis, and the mechanical properties were tested, demonstrating that the relative humidity in the drying process of the propellant affects its drying characteristics and subsequently its physical properties. The results showed that the drying of the double-base propellant at 50 °C with 60% relative humidity used shorter drying time and offered better drying quality. Therefore, this study can provide basic theoretical and data support for the control and regulation of relative humidity in the preparation process of a propellant. [ABSTRACT FROM AUTHOR]

Recently, the ambient drying method for the preparation of xerogels has attracted great attention due to its low cost and high drying efficiency. However, the strong capillary forces existing during ambient drying cause severe shrinkage or even collapse of the aerogels (called xerogels). Although chemical crosslinking or displacement of water by organic solvents have been tried to solve the problem, extensive usage of chemicals and time-consuming displacement processes seem to be environmentally unfriendly and complex. Herein, we reported a green and efficient method for the preparation of a lignocellulosic xerogel. The xerogel was fabricated by alkali freezing of unbleached eucalyptus fibers followed by water washing and ambient drying. The alkali freezing promoted fiber swelling and enhanced the hydrogen bonds among the fibers, resulting in the gelation of lignocellulosic fibers. In particular, the residual lignin in the fibers reduced the capillary force during the drying process. The resulting lignocellulosic xerogel achieved a low shrinkage rate (27.50%), low density (0.039 g cm−3 ), high porosity (97.57%), and excellent mechanical strength (782.23 kPa) as well as environmental stability, and low thermal conductivity (44.76 mW m−1 K−1 ). Similarly structured xerogels could be generated using recycled NaOH solution. This technique was suitable for production using various kinds of plant fibers, which shows its great scalable production prospects. [ABSTRACT FROM AUTHOR]

Prediabetes is defined as a state of moderate hyperglycemia. Here, we used freeze-dried seeds of Stenocereus stellatus (white tunillo) as a possible therapeutic strategy for the treatment of prediabetes. In the aqueous extract of freeze-dried seeds of white tunillo, polyphenols were identified using the Folin-Ciocalteu technique, separated by UPLC and analyzed by infrared spectrophotometry. Five well-defined peaks with good resolution were observed in the chromatogram of the aqueous extract obtained by UPLC. Two of these peaks corresponded to polyphenols with similarity to quercetin and rutin. The subchronic oral administration of freeze-dried seeds of white tunillo for 14 days in a prediabetes model in female Wistar rats reversed hyperglycemia and glucose intolerance. Treatment with the freeze-dried seeds reversed the decrease in the hepatic expression of Akt, eNOS, and p-eNOSSer 1177 but did not reverse the decrease in MnSOD, catalase, and GPx1. No changes in the expression of GPx4 and p-AktSer 473 were observed in the pathological state or with the treatment but there was an increase in the expression and activity of eNOS. The bioactive compounds present in the freeze-dried seeds of Stenocereus stellatus could provide guidelines for studying the mechanisms of action through which they reverse signs of prediabetes.

The properties of hydrogels and microgels, i.e. hydrogel particles, depend strongly on their water content. Based on our previously developed method to access the local water content in microgels, we performed fluorescence lifetime microscopy measurements at different stages of drying poly( N -isopropylacrylamide) (PNIPAM) microgels under ambient conditions. For this purpose, the red-emitting dye ATTO 655 was covalently attached to the microgels. Its emission is quenched by water molecules due to an energy transfer from the first excited state of the dye to a vibrational level of the water molecules. The quenching constant or, equivalently, the fluorescence lifetime, gives direct access to the local water concentration. We measured the fluorescence lifetime after spin-coating, reswelling and at different times of subsequent drying to follow the changes of water content during this process. We found that the microgels are not totally dry after spin coating, but drying them to their equilibrium moisture under ambient temperature and humidity conditions requires several hours. Additionally, we determined the moisture inside microgels in equilibrium at different air humidities. In summary, the method allows for a detailed investigation of the moisture inside hydrogels and gives straight-forward access to in situ and operando measurements of hydrogel systems.

Quantitative carbohydrate analysis faces challenges in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), including insufficient sensitivity and inconsistent spatial distribution of ion intensity. This study introduces an innovative sample preparation approach, the Rapidly Freeze-Drying Droplet (RFDD) method, aimed at overcoming these challenges by enhancing the homogeneity of the sample morphology and signal intensity in MALDI. Compared to conventional preparation methods, the RFDD method reduces the laser energy threshold and demonstrates a remarkable increase in signal intensity for carbohydrates, facilitating the detection of high-molecular-weight polysaccharides (>10 kDa). The RFDD-prepared samples exhibit a uniformly distributed signal intensity that overcomes the 'sweet spot' issue in MALDI. The enhanced signal intensity and reproducibility lead to reliable quantitative analysis of carbohydrates, eliminating the need for expensive isotopic standards in each sample. A straightforward and accessible approach is presented for general laboratories, revolutionizing carbohydrate analysis in MALDI-MS. [ABSTRACT FROM AUTHOR]

Colloidal monolayers serve as fundamental building blocks in fabricating diverse functional materials, pivotal for surface modifications, chemical reactivity, and controlled assembly of nanoparticles. In this article, we report the formation of colloidal monolayers generated by drying an aqueous droplet containing soft colloids confined between two hydrophilic parallel plates. The analysis of the kinetics of evaporation in this confined mode showed that: (i) for a significant portion of the drying time, the drops adopt a catenoid configuration; (ii) in the penultimate stage of drying, the catenoid structure undergoes division into two daughter droplets; (iii) the three-phase contact line remains pinned at a specific location while it continuously slips at all other locations. The interplay between interface-assisted particle deposition onto the solid substrate and the time evolution of particle concentration within the droplet during evaporation results in unique microstructural features in the deposited patterns. Notably, these deposit patterns exhibit reflection symmetry. The microstructural features of the dried deposits are further quantified by calculating the particle number density, inter-particle separation, areal disorder parameter, and bond orientational order parameter. The variation of these parameters for deposits formed under different conditions, such as by altering the spacing between parallel plates and the concentration of microgel particles in the droplet, is discussed., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

In this paper, we present a numerical model that can describe the pore formation/cavitation in viscoelastic food materials during drying. The food material has been idealized as a spherical object, with a core/shell structure and a central gas-filled cavity. The shell represents a skin as present in fruits/vegetables, having a higher elastic modulus than the tissue, which we approximate as a hydrogel. The gas-filled pore is in equilibrium with the core hydrogel material, and it represents pores in food tissues as present in intercellular junctions. The presence of a rigid skin is a known prerequisite for cavitation (inflation of the pore) during drying. For modeling, we follow the framework of Suo and coworkers, describing the inhomogeneous large deformation of soft materials like hydrogels - where stresses couple back to moisture transport. In this paper, we have extended such models with energy transport and viscoelasticity, as foods are viscoelastic materials, which are commonly heated during their drying. To approach the realistic properties of food materials we have made viscoelastic relaxation times a function of T g , the ratio of (moisture dependent) glass transition temperature and actual product temperature. We clearly show that pore inflation only occurs if the skin gets into a glassy state, as has been observed during the (spray) drying of droplets of soft materials like foods.T , the ratio of (moisture dependent) glass transition temperature and actual product temperature. We clearly show that pore inflation only occurs if the skin gets into a glassy state, as has been observed during the (spray) drying of droplets of soft materials like foods.

Two protein interaction peaks are observed in pharmaceutically-relevant protein (serum albumin) : disaccharide 1 : 1 and 1 : 3 (w/w) freeze-dried systems for the first time. In samples with a higher disaccharide content, the protein-protein distances are longer for both populations, while the fraction of the protein population with a shorter protein-protein distance is lower. Both factors would favor better stability against aggregation for disaccharide-rich protein formulations. This study provides direct experimental support for a "dilution" hypothesis as a potential stabilization mechanism for freeze-dried protein formulations.

Olive-mill wastewater (OMW), a by-product with high biological value and rich in phenolic compounds, is converted into spray-dried powders by using baker's yeast cells (YCs) as the carrier material. The encapsulation of OMW into YCs was also confirmed by Fourier transform infrared spectroscopy (FT-IR) analysis. The encapsulation yield (%) of powders for OMW phenolics was determined as 5.42 ± 0.33 and 4.02 ± 0.01% in YC microparticles non-treated and treated with high-pressure homogenization (HPH), respectively. The distorted structure of YCs, observed in scanning electron microscopy images, reduced the retention of OMW phenolics by YCs. HPH application made water removal easier, and the moisture content of YC-OMW powders was reduced from 5.13 to 3.72%. Compared to free OMW, the bioaccessibility indices (BI%) of individual phenolics were increased through yeast encapsulation, at the end of the intestinal stage, hydroxytyrosol and oleuropein could still be detected in encapsulated samples (BI% of 14-25 and 124-189%), but not in free OMW. Thus, YCs could be considered suitable encapsulating agents and show promising characteristics for technological application.

Anthocyanin-rich extract obtained from black chokeberry ( Aronia melanocarpa ) pomace was microencapsulated with spray drying by using different wall materials, i.e. , maltodextrin with dextrose equivalent 6 (MD6), maltodextrin with dextrose equivalent 20 (MD20) and the combination of MD20 with gum Arabic (MD : GA, 15 : 5 w/w), whey protein isolate (MD : WPI, 19 : 1 w/w), and xanthan gum (MD : XG, 19.5 : 0.5 w/w). Spray drying conditions were chosen as follows: inlet temperature of 150 °C, outlet temperature of 90 °C, 4.5 mL min -1 feed flow rate, 0.357 m 3 h -1 air flow rate, and an aspirator capacity of 100%. Physicochemical characteristics of the powders such as moisture content, particle size, capsule morphology, color, spray drying yield, encapsulation efficiency, total anthocyanin content, total and individual phenolic content, and total antioxidant activity were investigated. With all the parameters evaluated, MD : GA wall material provided better results particularly in terms of production yield and encapsulation efficiency. To conclude, black chokeberry by-product can be used as a source of polyphenols to produce value-added colored powders with bioactive properties which might have the potential to be used in food, nutraceutical and cosmetic industries.

A simple, scalable spray drying method was developed for high-yield epsilon iron oxide (ε-Fe2O3) synthesis. The ε-Fe2O3 particle size can be tailored by varying the annealing temperature and molar ratio of Fe/Si, producing a high-purity ε-phase. This strategy also enables ferromagnetic resonance tuning, making it potentially usable in millimeter-wave absorbers. [ABSTRACT FROM AUTHOR]

A porous V2O5 nanosheet is synthesized via freeze-drying followed by a heat-treatment process. Observably, transmission electron microscopy and atomic force microscopy analysis indicate that a porous and thin layer microstructure is achieved with V2O5. Electrochemical measurement demonstrates that the as-obtained V2O5 exhibits evident advantage toward the sodium/lithium ion storage. When evaluated as a cathode for sodium ion batteries, the V2O5 nanosheet delivers an initial discharge capacity of 199.8 mA h g−1. Even after 200 cycles at 50 mA g−1, the V2O5 nanosheet can retain a capacity of 123.9 mA h g−1, which is 2.3 times higher than that of bulk V2O5. Cyclic voltammetry and electrochemical impedance spectroscopy analysis further confirm that this rationally-designed porous nanosheet can increase the electroactive sites for the redox reaction and shorten the pathway of charge transfer, consequently leading to an enhanced capacitive sodium ion storage behavior. [ABSTRACT FROM AUTHOR]

In the present study, probiotic cells (Lactobacillus acidophilus) were encapsulated by spray drying technology to produce a probiotic powder using 20% maltodextrin and varied concentrations of gum arabic. The effects of processing conditions such as inlet air temperature (130-150 °C) and gum arabic concentration (0-10%) on the encapsulation efficiency, physical properties, and morphology were studied. For all the tested formulae, the moisture content, water activity, encapsulation efficiency, hygroscopicity, and wettability obtained were in the range of 4.59-9.05% (w.b.), 0.33-0.52, 65-89.15%, 12 to 21.15 g H2O per 100 g dry weight, and 116 s to 353 s, respectively. The Fourier transform infrared (FTIR) results have shown that gum arabic and maltodextrin show structural stability during spray drying. The encapsulated probiotic cells exhibited better viability of 4.03, 4.68, and 5.34 log CFU g-1 after 3 h of exposure to a simulated gastric fluid (SGF) solution at pH levels of 1, 1.5, and 2, respectively, compared to free cells. The viability of encapsulated cells stored for 12 weeks under refrigerated conditions (4 °C) and at room temperature (25 °C) was found to be 6.05 log CFU g-1 and 1.24 log CFU g-1, respectively.

Polyimide aerogels (PIAs) not only possess excellent thermodynamic properties but also have a high porosity structure, making them an exceptional protective and thermal insulation material, and further broadening their application scope in aerospace and other cutting-edge fields. In this work, a series of anisotropic polyimide aerogels (3,3',4,4'-biphenyltetracarboxylic dianhydride (S-BPDA), p -phenylenediamine (PDA), 4,4'-diaminodiphenyl ether (ODA)) with excellent properties were prepared. These PIAs were obtained by unidirectional freeze-drying and thermal amination of two different precursor solutions mixed in proportion. These PIAs possess an irregularly oval tubular structure, exhibiting pronounced anisotropy. (PIA-2 exhibits outstanding flexible resilience in the radial direction. It can still regain its original form after half an hour of compression by a universal testing machine, yet it cannot do so in the axial direction. The thermal diffusivity of PIA-5 in the radial direction at room temperature is as low as 0.067 mm 2 s -1 , and even at 200 °C, the thermal diffusivity is as low as 0.057 mm 2 s -1 . Meanwhile, the thermal diffusivity in the axial direction at room temperature is 0.11 mm 2 s -1 , surpassing the value of 0.106 mm 2 s -1 of aerogels prepared from monomeric raw materials and dried under supercritical conditions). PIAs exhibit outstanding thermal stability (the axial strength and modulus retention of PIA-8 at 200 °C are as high as 52.63% and 44.82%), and its weight loss temperature of 5% is as high as 603 °C and it has a glass softening temperature of 387 °C. PIAs also demonstrate exceptional flame retardancy in imitation flame retardant experiments and exhibit outstanding thermal insulation performance when heated on a 150 °C heating plate for 10 minutes (the radial surface temperature of PIA-5 was only 49.9 °C). These anisotropic PIAs materials exhibit outstanding flexible resilience, and thermal protection performance, holding significant importance for their widespread adoption as thermal insulation materials in aerospace, high-precision electronic components, and other domains., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Colloidal suspensions are the basis of a wide variety of coatings, prepared as liquids and then dried into solid films. The processes at play during film formation, however, are difficult to observe directly. Here, we demonstrate that optical coherence tomography (OCT) can provide fast, non-contact, precise profiling of the dynamics within a drying suspension. Using a scanning Michelson interferometer with a broadband laser source, OCT creates cross-sectional images of the optical stratigraphy of a sample. With this method, we observed the drying of colloidal silica in Hele-Shaw cells with 10 μm transverse and 1.8 μm depth resolution, over a 1 cm scan line and a 15 s sampling period. The resulting images were calibrated to show how the concentration of colloidal particles varied with position and drying time. This gives access to important transport properties, for example, of how collective diffusion depends on particle concentration. Looking at early-time behaviours, we also show how a drying front initially develops, and how the induction time before the appearance of a solid film depends on the balance of diffusion and evaporation-driven motion. Pairing these results with optical microscopy and particle tracking techniques, we find that film formation can be significantly delayed by any density-driven circulation occurring near the drying front.

The aim of this research was to use supercritical carbon dioxide (SC-CO 2 ) drying as a novel approach for generating sorghum protein concentrates/isolates with enhanced functional properties. Sorghum protein extracts were obtained from white whole-grain sorghum flour and were dried by two methods, namely, freeze-drying and SC-CO 2 drying. The collected proteins were characterized for their morphology, color, crystallinity, surface hydrophobicity, emulsifying activity index (EAI), creaming index (CI), foaming capacity (FC), foaming stability (FS), protein solubility, chemical interactions, and viscosity. The SC-CO 2 -dried proteins exhibited higher porosity compared to the freeze-dried ones with smaller particle sizes (∼5.1 vs. 0.4 μm, respectively). The XRD patterns indicated that the SC-CO 2 -dried proteins had a lower crystallinity than the freeze-dried proteins. However, the surface hydrophobicities of the freeze-dried and SC-CO 2 -dried proteins were similar. The EAI results showed that the emulsifying activity of freeze-dried protein powder (40.6) was better than that of SC-CO 2 -dried protein powder (29.8). Nevertheless, the solubility of SC-CO 2 -dried proteins was higher than that of freeze-dried proteins in most of the pHs investigated. Overall, the proposed SC-CO 2 drying method has the potential to generate porous protein powders with improved solubility that can be used in developing functional foods., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

Our study aimed to investigate the impact of various emulsifiers, namely whey protein isolate (WPI), soy protein isolate (SPI), and Tween 80 (Tw), on their ability to encapsulate cannabis oil with maltodextrin as the wall material. The physicochemical properties of the powder, the stability of the cannabinoids, and their bioaccessibility during static in vitro digestion were examined. The average diameter of fat globules in liquid nanoemulsions was 170, 259, and 95 nm for WPI, SPI, and Tw, respectively. The encapsulation efficiency was high for protein emulsifiers (>95%) compared to Tw (∼16%). Upon powder reconstitution in water, the emulsified fat droplets remained stable for WPI (176 nm); however, higher fat globule size (diameters of 346 nm and 210 nm) was observed for SPI and Tw powders, respectively. All oil powders had high solubility (>97%). The peroxide value (PV) showed nearly a fourfold increase for the oil extracted from the powder than the initial PV of bulk oil (5.2 mEq). However, UPLC-TUV analysis of the main cannabinoids (CBD, THC, and CBN) indicated that there is no significant difference between the various formulations and the bulk oil, except for lower Tw. The in vitro digestion model results showed higher bioaccessibility of the cannabinoids for Tw (∼53%) than for proteins (WPI ∼ 7% and SPI ∼ 10%). These findings suggest that the emulsifiers used for spray drying nanoencapsulation of cannabis oil have an impact on the encapsulation efficiency and cannabinoid bioaccessibility, highlighting the importance of choosing adequate emulsifiying agents for their optimal oral delivery.

The crosslinking and drying method of microcapsules prepared by complex coacervation has been investigated in order to achieve a better control of the oxidative stability of the final powder product. Methyl oleate was microencapsulated with gelatin and gum arabic as wall materials. For improving the oxidative stability of microcapsules, the crosslinking and drying method was optimized in order to obtain a product with a stable and dense wall layer structure. The wall layer crosslinked by transglutaminase was found to be more thermostable than other food-grade crosslinking agents. Combined uses of different crosslinking agents had been carried out for microcapsules obtained by freeze drying, and the product crosslinked in turn by transglutaminase and tannic acid exhibited the relatively best oxidative stability measured by oxidation induction time. However, a new method of organic solvent replacement drying was found to be more suitable for drying microcapsules, since this method could achieve better oxidative stability than freeze or spray drying even by using transglutaminase or tannic acid alone as the crosslinking agent. The SEM graphs showed that this new drying method could avoid ice crystal formation and reduce the external force during the drying process, thus effectively reducing the occurrence of micro-holes in the wall layer and inhibiting the adhesion between the microcapsules. From the analysis of the secondary structure measurement, this new drying method could convert irregular structures into α-helical structures, hence enhancing the compactness of the wall layer structure. The organic solvent replacement drying method is an economical and environmental method with promising application prospects.

Molecular weight (Mn) and conjugation of polymers can profoundly influence the performance of all-polymer solar cells (all-PSCs) via nanostructures of bulk heterojunctions (BHJs). To study the correlation between Mn and the performance of all-PSCs based on an acceptor with a flexible conjugation-break spacer (FCBS), three batches of acceptors, named PYTS, were synthesized with different number-average Mn from 9, 13 to 19 kDa. Blends with a polymer donor PBDB-T, the all-PSCs based on PYTS with Mn of 9 kDa and 19 kDa, exhibit power conversion efficiencies (PCEs) of 5.99% and 9.43%, respectively, primarily due to the increased short-circuit current density (Jsc) from 13.02 to 18.73 mA cm−2. To disclose the impact of Mn on device performance, dynamics of mixed PBDB-T:PYTS solutions to solid BHJs is studied by monitoring the drying process with home-made in situ multifunctional spectroscopy, which demonstrates that PYTS with Mn of 19 kDa has a longer drying time than the PYTS with Mn of 9 kDa. Prolonged drying of the BHJs with higher Mn PYTS facilitates more tightly packed structures with higher crystallinity. A systematic investigation on the nanostructures of BHJs, charge generation, transport and recombination is carried out with grazing-incidence wide-angle X-ray scattering (GIWAXS), transient absorption spectroscopy (TAS) and characterization of all-PSCs. The results indicate that increased crystallinity in the BHJs benefits exciton dissociation, electron transport, prolonged carrier lifetimes, and decreased non-geminate recombination rate constants in the corresponding devices. Combining the in situ study of drying and the investigation on films and devices provides us a comprehensive understanding of the interplay between Mn, the drying process, the nanostructures of BHJs and device performance. This work not only emphasizes the essential role of Mn in governing the device performance, but also exhibits recorded film formation through the in situ spectroscopy, enabling us to manipulate the nanostructure of BHJs by optimizing Mn of polymers and processing parameters. [ABSTRACT FROM AUTHOR]

The tert-butanol (TBA)-water system is studied in relation to increasing the efficiency of obtaining pharmaceutical powders by freeze-drying. Trehalose was used as a model target product. We report the X-ray diffraction and thermal analysis data which add surprising new information to the phase diagram of this previously repeatedly studied system. The freezing protocol has a strong impact on the specific surface area of the trehalose freeze-dried cakes and on the primary drying time. This is related to a discrepancy between the kinetic and thermodynamic stabilities of several TBA hydrates: di-hydrate (H1), heptahydrate (H2), and decahydrate (H3).

Akkermansia muciniphila, an abundant member of the human gut microbiota, has been suggested as a potential next-generation probiotic. However, its high sensitivity to oxygen limits the development of dosage protocols. Here, we describe microencapsulation, in a xanthan and gellan gum matrix, and a subsequent freeze-drying protocol for A. muciniphila DSM22959. For comparison Lactobacillus plantarum subsp. plantarum ATCC14917 was microencapsulated and freeze-dried using similar protocols. Four different mixtures were tested for cryoprotective properties: sucrose 5% plus trehalose 5%; agave syrup 10%; skim milk 10%, glucose 1%, yeast extract 0.5%, and mannitol 2.5%; as well as peptone 0.1% plus sorbitol 1.2%. Milli-Q-water served as control. Only cryoprotectant solutions with high sugar or protein content significantly improved the survival of both strains during freeze-drying. Microencapsulated cells were stored aerobically or anaerobically for 1 month at 4 °C or 25 °C. Survival of A. muciniphila was significantly better when stored anaerobically at 4 °C. The survival of microencapsulated L. plantarum, was relatively stable at both temperatures under anaerobic conditions. Survival of microencapsulated cells was compared with that of free cells during in vitro simulated upper gastrointestinal tract (GIT) transit at fasted and fed state. During in vitro simulated stomach passage, encapsulation significantly improved survival and viable cells remained at relevant levels after the entire simulated upper GIT transit. In conclusion, we here report a protocol for encapsulating A. muciniphila giving acceptable storage stability and enhancing survival during in vitro simulated upper GIT transit and thus constitutes an important step towards enabling future use of this important member of the human colonic microbiota as a probiotic.

We have developed a poly(dimethylsiloxane) (PDMS) microfluidic chip to study the directional drying of a colloidal dispersion confined in a channel. Our measurements on a dispersion of silica nanoparticles once again revealed the phenomenology commonly observed for such systems: the formation of a porous solid with linear growth in the channel at short times, slowing down at longer times as the evaporation rate decreases. The growth of the solid is also accompanied by mechanical stresses that are released by the delamination of the solid from the channel walls and the formation of cracks. In addition to these observations, we report original measurements using hydrophilic filler in the PDMS formulation used (Sylgard-184). When the PDMS matrix is in contact with water, water molecules pool around these hydrophilic sites, resulting in the formation of microscopic water clusters whose size depends on the water potential ψ . In our work, we have used these water clusters to estimate the water potential profile in the channel as the porous solid grows. Using a transport model that also takes into account solid delamination in the channel, we then linked these water potential measurements to the hydraulic permeability of the porous solid. These measurements finally enabled us to show that the slowdown in the evaporation rate is due to the invasion of the porous solid by air/water nanomenisci at a critical capillary pressure ψ cap .

Hydrogels, water-saturated polymer networks find widespread use in soft robotics, biomedical, pharmaceutical and food industries. Both solid and water constituents of hydrogels are sensitive to external stimuli such as temperature, humidity, osmolarity, and light. For instance, common hydrogels swell or shrink in the presence of chemical potential gradient between the sample and surrounding environment. Corresponding changes in internal water content lead to significant changes in mechanical properties of hydrogels. Besides, internal stresses build up if the gel samples are constrained during swelling or dehydration. In the present research, we utilize modal analyses technique on drying hydrogels to identify dehydration-induced changes in elastic moduli and internal stresses. In particular, natural frequencies and damping ratios of the first two axisymmetric transverse vibration modes are measured on clamped gelatin disks using non-contact laser vibrometry at various water loss states. Experimental modal frequencies are then compared to the predictions of a pre-stressed thick plate model. The evolutions of elastic moduli and internal stresses for water losses up to 80% are identified. The broadband loss capacity of gelatin is also determined from the measured modal damping ratios. Highly transient mechanical response observed on the gelatin disks further demonstrates the need for non-contact and rapid mechanical characterization of hydrogels. As illustrated in this work, vibration and wave-based techniques are promising candidates to fulfill that need.

Droplets containing polyvinylpyrrolidone (PVP) dissolved in ethanol display a distinctive scalloped pattern at the rim while spreading and drying on a high-energy surface. Two distinct spreading regimes are observed, leading to the formation of a thin film with a uniform height that extends from the original droplet. An experimental study indicates polymer accumulation at the edge containing trace water, resulting in a surface tension gradient across the droplet, enhancing the droplet's spreading. This fast-spreading film develops a ridge at the contact line and becomes unstable. The influence of evaporation within the droplet shows no significant effect on the wavelength of the instability. Instead, the magnitude of the surface tension gradient and the surface energy of the substrate emerge as the dominant factors influencing the instability. This observation is validated by saturating the environment surrounding the droplet with ethanol vapour to reduce evaporation or employing solvents with low vapour pressure. Additionally, PVP in ethanol droplets deposited on hydrophobic substrates demonstrate a stable and pinned contact line, contrasting the behaviour observed on high-energy surfaces. By identifying the critical overlap concentration of the polymer, the transitional threshold between the scalloped instability and ringlike morphology is determined. The scalloped instability can be suppressed by removing residual water from the solution, eliminating the surface tension gradient, indicating that Marangoni forces are the underlying cause of the observed instability. The long-wave evolution equation, assuming a constant Marangoni shear flow, accurately predicts the most unstable wavelength, demonstrating good agreement with experimental observations.

The objective of this study was to investigate the impact of protein type (sodium caseinate and pea protein isolate) and protein to sugar beet pectin mixing ratio (5 : 1 and 2 : 1) on complex coacervate formation, as well as the impact of the finishing technology (freeze-drying and spray-drying) for improving the viability of encapsulated Lactobacillus rhamnosus GG (LGG) in complex coacervates during simulated sequential gastrointestinal (GI) digestion. The physicochemical properties of LGG encapsulated microcapsules in liquid and powder form were evaluated. The state diagram and ζ-potential results indicated that pH 3.0 was the optimum pH for coacervate formation in the current systems. Confocal laser scanning microscopy (CLSM), viscoelastic analysis, and Fourier transform infrared spectroscopy (FTIR) confirmed that the gel-like network structure of the complex coacervates was successfully formed between the protein and SBP at pH 3.0 through electrostatic interaction. In terms of physiochemical properties and viability of LGG encapsulated in the microcapsule powder, the drying method played a crucial role on particle size, microstructure and death rate of encapsulated LGG during simulated sequential GI digestion compared to protein type and biopolymer mixing ratio. For example, the microstructure of spray-dried microcapsules exhibited smaller spherical particles with some cavities, whereas the larger particle size of freeze-dried samples showed a porous sponge network structure with larger particle sizes. As a result, spray-dried LGG microcapsules generally had a lower death rate during simulated sequential gastrointestinal digestion compared to their freeze-dried counterparts. Among all samples, spray-dried PPI-SBP microcapsules demonstrated superior performance against cell loss and maintained more than 7.5 log CFU per g viable cells after digestion.

Suspended particles in a solvent form a packed film when the solvent evaporates. We investigated film growth rates in a narrow channel on a tilted drying interface and observed clear differences in the rates of film growth. Films grew faster at one end and slower at the other; thus, the slope of the packing front, i.e., the boundary between the packed film and the drying suspension, changed as drying proceeded. However, the difference in film growth rates became smaller as the slope of the packing front changed and the rates of film growth at the either end ultimately became identical. We found that the differences in the rates of film growth were proportional to cos, where is the angle defined by the slope of the packing front. We constructed a mathematical description to successfully express the time evolution of both the difference in the growth rates and the packing front angle. Relationships between drying-induced flow of bulk suspensions and transport of suspended particles to the tilted packing front are discussed. [ABSTRACT FROM AUTHOR]

Dual-gasochromic supraparticles that undergo rapid eye-readable and gas-specific colour changes upon reaction with hydrogen or ammonia are reported. This functionality is achieved by tailoring the solid–liquid–gas interface within the mesoporous framework of supraparticles via spray-drying. [ABSTRACT FROM AUTHOR]

Although Saccharomyces cerevisiae has shown potential utilization as a bio-vehicle for encapsulation, there are no reports about the functionality of natural colorants encapsulated using yeast cells. The main objectives of this study were to produce natural food coloring by encapsulating extracts from grape pomace (GP) and jabuticaba byproducts (JB) in brewery waste yeast and evaluate the functionality of the pigments by their incorporation into yogurts. Particles produced by the encapsulation of extracts from GP and JB in S. cerevisiae using 5% of yeast had the highest encapsulation efficiencies for both anthocyanins (11.1 and 47.3%) and phenolic compounds (67.5 and 63.6%), the highest concentration of both bioactives during storage and stable luminosity. Yogurts showed a pseudoplastic behavior and were considered weak gels. Colored yogurts had acceptance indexes between 73.9 and 81.4%. This work evidenced the utilization of enriched yeasts as coloring agents and interesting additives for the production of functional foods.

The crystallization of inorganic oxide framework in mesoporous materials is a general issue for every application field. An amount of heated air to recover mesoporous Al2O3 powders using a spray dryer has made a significant difference in the crystallization behavior into an α-Al2O3 phase in addition to the variation in their pore diameter. The crystallization into α-Al2O3 at 850 °C was accelerated with mesoporous Al2O3 powder prepared with Pluronic F127 recovered from a large amount of heated air. In contrast, the powder recovered from a small amount of heated air resulted in only γ-Al2O3 at the same calcination temperature, even though they were recovered from the same precursor solution. Further investigation with other amphiphilic organic templates with varying hydrophilicity and less hydrophilic Pluronic P123 resulted in more accelerated crystallization into α-Al2O3; however, the formation of α-Al2O3 was not detected with hydrophilic Pluronic F68. Solvent evaporation from the precursor solution was rapidly completed with a large amount of heated air and a less hydrophilic amphiphilic organic template. Therefore, the annealing of the as-recovered mesoporous Al2O3 powder was prolonged to accelerate the subsequent crystallization into α-Al2O3 at 850 °C. [ABSTRACT FROM AUTHOR]

The evaporation of drops of colloidal suspensions plays an important role in numerous contexts, such as the production of powdered dairies, the synthesis of functional supraparticles, and virus and bacteria survival in aerosols or drops on surfaces. The presence of colloidal particles in the evaporating drop eventually leads to the formation of a dense shell that may undergo a shape instability. Previous works propose that, for drops evaporating very fast, the instability occurs when the particles form a rigid porous solid, constituted of permanently aggregated particles at random close packing. To date, however, no measurements could directly test this scenario and assess whether it also applies to drops drying at lower evaporation rates, severely limiting our understanding of this phenomenon and the possibility of harnessing it in applications. Here, we combine macroscopic imaging and space- and time-resolved measurements of the microscopic dynamics of colloidal nanoparticles in drying drops sitting on a hydrophobic surface, measuring the evolution of the thickness of the shell and the spatial distribution and mobility of the nanoparticles. We find that, above a threshold evaporation rate, the drop undergoes successively two distinct shape instabilities, invagination and cracking. While permanent aggregation of nanoparticles accompanies the second instability, as hypothesized in previous works on fast-evaporating drops, we show that the first one results from a reversible glass transition of the shell, unreported so far. We rationalize our findings and discuss their implications in the framework of a unified state diagram for the drying of colloidal drops sitting on a hydrophobic surface.

We study the formation of a glassy skin at the air interface of drying polymer solutions. We introduce a simple approximation, which is valid for most diffusion problems, and which allows us to derive analytical relationships for the polymer concentration as a function of time. We show that the approximate results differ by less than 15% from those obtained by numerically solving the diffusion equation. We use the approximation to study skin formation in evaporating solutions. We focus on the influence of variations of the mutual diffusion coefficient with concentration, when the latter decreases sharply at high concentrations, as observed in the vicinity of the glass transition. We show that the skin thickness depends very strongly on the exponent characterising the decrease of the diffusion coefficient, in contrast to the polymer volume fraction at the interface, which varies only slightly with the exponent.

Inhalable metal organic framework (MOF) aerosols have been developed via spray drying as a therapy for multi-drug resistant (MDR) tuberculosis (TB). The CuPOA2 (pyrazinoate acid) MOFs can be tailored to exhibit a respirable mass median aerodynamic diameter (MMAD) of 2.6 μm. This method is repeated to manufacture Gd0.1Cu0.9(POA)2 MOFs for inhalable theragnostics. [ABSTRACT FROM AUTHOR]

The Maillard reaction products (MRPs) of whey protein isolate (WPI) and xylooligosaccharides (XOS) were prepared by a moist heat method for use as protectants to encapsulate Lactobacillus rhamnosus via spray drying. The protective effects of MRPs on bacterial cells during drying, storage, and in vitro digestion were explored. FTIR results indicated that MRPs were successfully prepared. All MRPs showed good thermo-protective effect on the bacteria, and the survival ratio achieved with 1 : 2 XOS-WPI as a wall material reached 99.83 ± 8.44%, which was around 2 times as high as that of the WPI wall material and 1.5 times as high as that of the 1 : 2 XOS-WPI mixture. The dried lactobacilli showed similar growth curves to the fresh culture. After 10 weeks of storage at 4 °C, the decrease in the bacterial activity was less than 1 log CFU g-1 for all types of microcapsules, while the microcapsules composed of all MRPs had better storage stability. MRPs improved the stability of microcapsules during in vitro digestion. The number of viable bacteria in 1 : 2 XOS-WPI MRPs microcapsules was maintained at 4.09 ± 0.59 × 109 CFU g-1 after simulated gastrointestinal digestion for 4 hours, which only decreased by 0.20 log CFU g-1.

MnO2 as a versatile transition metal oxide has multiple crystalline forms, such as δ-, α-, γ-, and β-phases, and they have important applications in miscellaneous domains, but there remains a huge challenge to simultaneously manage the crystal and morphology structure of MnO2 by a facile approach. Herein, we report a simple post-treatment method for the synthesis of MnO2 with different structures. The transition from δ-MnO2 nanosheets to α-MnO2 nanowires or γ-MnO2 nanoflakes can be achieved by simply varying the water evaporation rate of the wet synthesized samples during the drying process at a temperature of 60 °C. KMnO4 or NaMnO4 was used to prepare layered δ-MnO2, and the drying conditions were altered to adjust the evaporation rate of water, so that the K+ or Na+ ions in the layered structure were redistributed and served as templates for the evolution of the tunnel structure. Impressively, δ-MnO2 is enabled to achieve a high specific capacitance of 586 F g−1. Our findings greatly reduce the energy required for the transition between different phases of MnO2, unveil the directional assembling of the [MnO6] unit under a controlled drying environment as well as the pivotal role of the drying conditions in determining the crystalline phase of MnO2, and provide a novel strategy for the structural engineering of metal oxides. [ABSTRACT FROM AUTHOR]

A novel microspheric cocrystal consisting of a 1 : 1 molar ratio of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and 2,4-dinitroimidazole (2,4-DNI) was synthesized by a spray-drying process utilizing our self-developed equipment, which is economical, productive and green. The yield of CL-20/2,4-DNI was 97.65%, far above other spray-drying methods. The structure of the cocrystal and its intermolecular interactions were calculated by Materials Studio program; the cocrystal CL-20/2,4-DNI was most likely to crystallize in P21/C group, and density of states analysis confirms that C–H⋯O interactions were the main force in forming the cocrystal. PXRD combined with DSC and FT-IR results also confirm the cocrystal CL-20/2,4-DNI. The PXRD measurements show that CL-20/2,4-DNI has a new crystal phase, which indicates that the cocrystal, rather than physical mixture, was formed, and the IR spectra gives supplementary confirmation for the existence of C–H⋯O bonds between CL-20 and 2,4-DNI. The DSC shows the thermal decomposition peak temperature of 257.2 °C, which suggests that the microspheric CL-20/2,4-DNI has good thermal stability. Moreover, the SEM results show that microspheric CL-20/2,4-DNI cocrystals with D50 of 518.25 nm were prepared, and the cocrystal exhibits surprisingly low sensitivity, up to 60.4 cm, in impact drop tests. The predicted detonation velocity of CL-20/2,4-DNI is 9324 m s−1 higher than that of HMX. CL-20/2,4-DNI is a promising explosive that can be applied in weapons. [ABSTRACT FROM AUTHOR]

Protective agents used in spray drying protect the activity of lactic acid bacteria (LAB) by stabilizing the subcellular structures, constituting a protective layer at the cellular surface, or having mild drying kinetics. The effects of a reputed protectant, whey protein isolate (WPI), on Lactobacillus rhamnosus GG (LGG) were examined by exposing the cells to WPI solution to induce protein adsorption at the cellular surface prior to spray drying. WPI-treated LGG demonstrated enhanced thermotolerance with cell survival increased by 1.64 log after heat treatment. The survival after spray drying was significantly decreased from 45.75% to 8.6% and from 32.96% to 10.44%, when the WPI-treated cells were resuspended in trehalose solution or reconstituted skimmed milk as protectant, respectively, associated with decreased growth capability and metabolic activity. The contact with WPI appeared to stimulate the cellular response of LGG. With well-maintained cell viability and intact cellular membrane, the metabolic activity of WPI-treated LGG was decreased, and subsequent resuspension of the cells in trehalose solution led to a reduction in the stability of the cellular surface charge. The WPI-treated cells showed marginally increased surface roughness, indicating possible WPI attachment, but there was no thick protein coverage at the cellular surface and the size distribution of cells was unaffected. It was proposed that the enhanced thermotolerance and the decreased survival of spray-dried LGG could be linked to the cellular response toward WPI and protectant media, which may vary among individual LAB strains. Modulating the strain-specific interactions between the LAB cells and the protectant constituents could be crucial to maximizing cell viability retention after spray drying.

Idesia polycarpa Maxim. leaves are an excellent source of hydroxycinnamic acid derivatives and have drawn special attention due to their various biological activities. However, the effects of post-harvest treatment on the structure-activity relationships of hydroxycinnamic acid derivatives in leaves of I. polycarpa are still unknown. In the current study, we compared the contents of unstable compounds in leaves with four drying methods, namely sun-drying, freeze-drying, shade-drying, and oven-drying. We found that the four hydroxycinnamic acid derivative isomers of leaves were significantly affected after drying processing with four different drying methods. Consequently, the underlying mechanisms responsible for the variation of these compounds during the drying processes have been well elucidated: UV lighting induced the isomerization of 1-[(6'-O-(E)-p-coumaroyl)-β-d-glucopyranosyl]-oxy-2-phenol (1) and 1-[(4'-O-(E)-p-coumaroyl)-β-d-glucopyranosyl]-oxy-2-phenol (3) into 1-[(6'-O-(Z)-p-coumaroyl)-β-d-glucopyranosyl]-oxy-2-phenol (2) and 1-[(4'-O-(Z)-p-coumaroyl)-β-d-glucopyranosyl]-oxy-2-phenol (4). Also, heat (exceeding 20 °C) led to the rearrangement of the (E/Z)-p-coumaric acid moiety of compounds 3 and 4, of which the 4-O-acylglucoses changed into the 6-O-acylglucoses to generate compounds 1 and 2, respectively. Interestingly, the hepatocyte-free fatty acid accumulation in OA-induced steatosis-conditioned HepG2 cells decreased by 65.00%, 10.69%, and 47.00%, respectively, following treatment with compounds 2, 3 and 4, and compound 1 presented no lipid-lowering activity. In addition, the bioactivities of compounds 2 and 4 were substantially enhanced by 58.42% and 25.33% with the sun-drying method compared to the freeze-dying methods. Our study suggests that sun-drying processing is the best method among the four drying processing methods of I. polycarpa Maxim. leaves.

A facile freeze-drying assisted biotemplated route is developed to synthesize Na3V2(PO4)3 embedded in a N-doped three-dimensional mesoporous carbon framework, which has a superior initial discharge capacity and stability for Na-ion batteries. [ABSTRACT FROM AUTHOR]

We report the extension of the common β-diketimine proligand class, RArnacnacH (HC(RCNAr)2H), where R is an alkyl group such as Et or iPr, plus Ph, and Ar is a sterically demanding aryl substituent such as Dip = 2,6-diispropylphenyl, Dep = 2,6-diethylphenyl, Mes = 2,4,6-trimethylphenyl or mesityl, Xyl = 2,6-dimethylphenyl, via one-pot condensation procedures. When a condensation reaction is carried out using the chemical dehydrating agent PPSE (polyphosphoric acid trimethylsilylester), β-diketiminate phosphorus(V) products such as (iPrMesnacnac)PO2 can also be obtained, which can be converted to the respective proligand iPrMesnacnacH via alkaline hydrolysis. The RArnacnacH proligands can be converted to their alkali metal complexes with common methods and we have found that deprotonation of iPrDipnacnacH is significantly more sluggish than that of related β-diketimines with smaller backbone alkyl groups. The basicity of the RArnacnac− anions can play a role in the success of their salt metathesis chemistry and we have prepared and structurally characterised the EtDipnacnac-derived silicon(II) compounds (EtDipnacnac)SiBr and (EtDipnacnac')Si, where EtDipnacnac' is the deprotonated variant MeCHC(NDip)CHC(NDip)Et. [ABSTRACT FROM AUTHOR]