Stable Particle Size Research Articles

Impact of Pleurotus ostreatus β-Glucans on Oxidative Stability of Active Compounds Encapsulated in Powders during Storage and In Vitro Digestion.

Polyunsaturated fatty acids and α-tocopherol were encapsulated in powders by spray drying using maltodextrins DE 12 as wall material and different emulsifiers (Tween®20, acacia gum or β-glucans-rich extracts from Pleurotus ostreatus). The aim was to study the effects of the surfactants on: (a) the oil droplet size distribution and α-tocopherol stability during in vitro digestion, and (b) the oxidative stability during 15 days of accelerated storage. Acacia gum sample had the most stable particle size distribution up to the gastric phase, but showed a significant α-tocopherol degradation prior to the intestinal stage. On the contrary, β-glucan-samples displayed a bimodal distribution in the oral and gastric phases but retained α-tocopherol up to the beginning of the intestinal stage. At the end of intestinal stage, no α-tocopherol was found in the samples. The storage study showed that β-glucans improved the oxidative stability of the powders, which displayed 82% α-tocopherol retention after 5 days under accelerated conditions (60 °C), corresponding to 310 days at 20 °C, while acacia gum and Tween® 20 did not delay α-tocopherol degradation. Results highlight the potential antioxidant activity of β-glucans used as emulsifying agents during in vitro digestion and accelerated aging conditions.

Comparison of low- and high-methoxyl pectin for the stabilization of whey protein isolate as carrier for lutein

Lutein (LUT) is a natural colorant and antioxidant that is found in vegetable sources such as marigold flowers and green leaves. Due to its instability under some environmental conditions, carrier materials are desirable to protect and incorporate this natural colorant into food products. Whey protein isolate (WPI) and pectin have been studied as a well-known system to entrap active compounds. The first part of this study evaluated the effect of total concentration (0.2 and 0.4%) and biopolymer ratio (3:0, 3:1, 3:2, 3:3, 2:3, 1:3 and 0:3) of the WPI:low methoxyl pectin (LMP) nanocomplexes (NCs). Subsequently, the influence of the type of pectin, including LMP and high methoxyl pectin (HMP) for the optimization of NCs was studied at different concentrations of pectin at ratios of 4:0, 4:1, 4:2, 4:3, 4:4 and 0:4 (WPI:LMP/HMP). Moreover, the loading of LUT into the NCs was investigated to assess its effect on the particle and stabilization properties. All NCs showed a stable particle size at pH 5.0 and precipited at lower pH values. NCs loaded with LUT at a ratio of 4:1 (WPI:LMP) and pH 5.0 showed the most stable system with a particle size of 204 ± 5 nm after 30 days. The binding properties showed a maximum binding constant (Kq) of 5.35 × 1013 M−1 S−1 at pH 7.0, which proves that this is the optimal pH condition to bind the LUT to the WPI.

Sustainable Polyurethane–Lignin Aqueous Dispersions and Thin Films: Rheological Behavior and Thermomechanical Properties

Sustainable aqueous polyurethane (PU) dispersions derived from castor oil and lignosulfonate (LS) have been successfully synthesized with stable nanoscale morphology and average particle sizes as s...

Polyelectrolyte Nanoparticles of Amphiphilic Chitosan/Pectin from Banana Peel as Potential Carrier System of Hydrophobic Molecules.

In this study, pectins were extracted from banana wastes Musa paradisiaca under different acidic conditions, obtaining pectins with different degrees of esterification (DE) depending on the acid type and pH. The formation of the polyelectrolyte nanoparticles was evaluated according to the DE of the pectin, the mass ratio of the polymers of pectin to amphiphilic chitosan (AmCh), and their concentration. The properties of the polyelectrolyte nanoparticles were evaluated at different pH and temperatures. The pectin with 24.3% DE formed polyelectrolyte nanoparticles through the electrostatic interaction with AmCh, which was evidenced by changes in the zeta potential and particle size. The study of mass ratio AmCh:Pectin, to get a stable system, showed that it must be at least equal (1:1), or AmCh must be in higher proportion (6:1, 50:1, 100:1), and the polymers concentration must be 1 mg/mL. The study of the temperature effect showed that, when the temperature increases, the particle size decreases, and the pH study showed a stable particle size for the polyelectrolyte nanoparticles in the range of pH 5–6. Nile Red (NR), a hydrophobic molecule, was encapsulated in the polyelectrolyte nanoparticles with a loading capacity of 1.8% and an encapsulation efficiency of 80%.

Preparation of Lipid Nano-Bubbles as Contrast Agent Material for Tumor Ultrasound Diagnosis of Breast Cancer

Ultrasound diagnostic technology has higher application values in tumor diagnosis due to its higher spatial resolution and no radiation. Ultrasound lipid nanobubble contrast material can further improve the accuracy of tumor diagnosis. Therefore, the liposomes were used as shells to encapsulate bio-inert gases to prepare nano-scale microbubbles NBs. Meanwhile, the Annexin V molecules were connected through the conjugation of biotin-avidin to prepare targeted nano-scale ultrasound contrast agents (UCAs) Annexin V-Nanobubbles (AVNBs). The tumor-bearing mice apoptosis models were constructed by injecting human breast cancer MDA-MB231 cells, and the nano-scale UCA AV-NBs was used for ultrasound diagnosis, data collection, and statistical analysis. The results showed that the prepared AV-NBs were nano-sized hollow spheres with relatively stable particle size, zeta potential, and excellent stability. By verifying the constructed mice apoptosis models, it was found that mice heterotopic transplantation tumor apoptosis models were successfully constructed. When the mice models were observed by ultrasound, the apoptosis index of the cell was found to be positively correlated with the enhancement degree of the image. Therefore, the enhancement effect of the targeted UCA AV-NBs was obvious. The AV-NBs could be specifically targeted to the apoptotic region of tumor tissue in vivo, which was also slightly enriched in the liver and kidney. Therefore, the experiment found that the targeted nano-scale UCA AV-NBs combined with ultrasound detection could significantly enhance the diagnostic accuracy of breast cancer tumors, which provided the experimental evidence for early tumor diagnosis and evaluation.

Effects of calcium chelation on the neutralization of milk protein isolate and casein micelle reassembling.

Rehydration in an alkaline solution has been shown to improve the rehydration behaviour of milk protein isolate (MPI). In this study, the focus is on citric acid neutralization of MPI powder dissolved in alkaline solution. The results showed that alkalization induced more negative zeta-potential compared to MPI control, reducing it from -22.4mV to -32.6mV. Neutralization had a relatively similar zeta-potential value as alkalized sample. Sodium carbonate addition increased pH and caused a consequential reduction of ionic calcium in aqueous phase and, neutralization caused a small increase in ionic calcium. Soluble aggregate of κ-casein protein and whey protein was suggested in alkalization and neutralization process by non-reducing SDS-PAGE. In addition, neutralization kept a stable colloidal particle size for pHs decreased to pH 9,8 and 7; however, alkalization and neutralization created casein aggregates of larger colloidal particle size than primary casein micelle in control MPI.

Novel fluorinated polycationic delivery of anti-VEGF siRNA for tumor therapy

Small-interfering RNA (siRNA) can specifically silence disease gene expression, bringing hope for the effective treatment of gene-related diseases. However, its use in vivo is limited due to the lack of efficient carriers. Therefore, it is necessary to construct carriers with high efficiency, low toxicity and serum stability. As a promising polycation carrier, polyethylenimine (PEI) can be further modified with a fluorine-containing alkyl chain that brings hydrophobic and oleophobic characteristics to its surface. In this study, low molecular weight PEI 1.8 kDa was selected and fluorinated through an anhydride reaction, and the product was named PEIF. In vitro experiments have shown that PEIF/siRNA polyplexes have suitable and stable particle size and potential, compress nucleic acids at a very low w/w ratio, and have the ability to effectively silence specific genes with low cytotoxicity. Compared with the polyplexes prepared using PEI 25 kDa, the PEIF/siRNA polyplexes were more stable in serum, showed a better antiangiogenic ability in in vivo experiments, and had a better tumor inhibition effect. The above results indicate that fluoropolymers based on the fluorine effect have great potential as gene delivery carriers for tumor therapy.

Application of Nanomaterials in Regulating the Fate of Adipose-derived Stem Cells.

Adipose-derived stem cells are adult stem cells which are easy to obtain and multi-potent. Stem-cell therapy has become a promising new treatment for many diseases, and plays an increasingly important role in the field of tissue repair, regeneration and reconstruction. The physicochemical properties of the extracellular microenvironment contribute to the regulation of the fate of stem cells. Nanomaterials have stable particle size, large specific surface area and good biocompatibility, which has led them being recognized as having broad application prospects in the field of biomedicine. In this paper, we review recent developments of nanomaterials in adipose-derived stem cell research. Taken together, the current literature indicates that nanomaterials can regulate the proliferation and differentiation of adipose-derived stem cells. However, the properties and regulatory effects of nanomaterials can vary widely depending on their composition. This review aims to provide a comprehensive guide for future stem-cell research on the use of nanomaterials.

Stability of cobalt-based Fischer–Tropsch catalyst supported on oxidized carbon nanotubes

The stability of 20[Formula: see text]wt.% Co/CNT catalyst was tested in the Fischer–Tropsch synthesis and the structural transformations both in the catalyst and support were analyzed. The catalyst showed high conversion and stable selectivity during three weeks of the test, which was attributed to the optimal and stable cobalt particle size of [Formula: see text]13–14[Formula: see text]nm promoted by the support pre-oxidation. XPS, Raman, and nitrogen adsorption data revealed that the carefully chosen catalyst annealing and reduction conditions ensured the preservation of the support structure.

TECHNOLOGY IMPROVEMENT OF HIGH-DISPERSIVE METALLIC IRON POWDERS BASED ON SEDIMENTS OF IRON REMOVAL STATION

Sediments from iron removal stations are a source of environmental pollution. It is necessary to find effective and eco-friendly methods of sediment disposal. The paper investigates the properties of iron-containing sediment in order to develop a technology for its further utilization. It is shown that sediments from the iron removal station of Velizhansky water intake have a stable chemical composition with about 70 % Fe2O3, and a stable particle size distribution, i.e. 20 μm for ≈ 87 % of particles. These parameters allow developing a flow chart for iron reduction in heated carbon monoxide. The involvement of sediments from iron removal stations in the high-dispersive metallic iron powder production eliminates the sediment deposit at landfills or storage tanks and creates a new raw material base for additive technologies.

A multifunctional carbon nanotube reinforced nanocomposite modified via soy protein isolate: A study on dispersion, electrical and mechanical properties

Excellent multifunctional polymeric nanocomposite cannot be achieved without good dispersion and well protection of nanofillers, for which a highly efficient, cost-effective and environmental benign nanofiller treatment approach is demanded. Herein, we report that soy protein isolate (SPI), an extracted protein from soybean, is applied as a highly performed bio-surfactant to treat carbon nanotubes (CNTs), resulting in nanocomposite with tremendously improved dispersion, electrical and mechanical properties. TEM, UV–vis and dynamic light scattering (DLS) and real-time optical microscopic characterizations show that, compared with a conventional surfactant, sodium dodecylsulfate (SDS), SPI more effectively and efficiently functionalize CNTs with less agglomerates and more stable particle size distribution. The electrical conductivity of the SPI-CNTs/epoxy increased by 6 orders of magnitude at 0.5 wt% vs pure epoxy, which is 4 orders higher than the pristine CNTs/epoxy and even 1 order higher than that of the SDS treated counterpart. The tensile modulus, strength and fracture toughness of the SPI-CNTs/epoxy increased by 27%, 24% and 32% at 1.0 wt% loading of CNTs, respectively, which is 20%, 26% and 18% higher than the pristine CNTs/epoxy and 10%, 23% and 21% higher than the SDS-CNTs/epoxy. The in-situ tensile test accompanied by digital image correlation technique (DIC) shows that cracks are effectively arrested by the SPI-CNTs while SDS-CNTs cannot. These results establish a solid foundation for the application of SPI in the polymeric nanocomposite fields.

Facile construction of AIE-based FRET nanoprobe for ratiometric imaging of hypochlorite in live cells

Fluorescence resonance energy transfer (FRET) nanoprobes based on aggregated induced emission (AIE) molecules are promising for the monitoring of biomolecules in living cells, but this nanoprobe for reactive oxygen species (ROS) has rarely been reported. Here, a novel AIE-based FRET nanoparticles (NPs) is developed for ratiometric detection and imaging of hypochlorite in live cells. Different to common FRET-based nanosensors, the NPs is prepared via facile co-assembly strategy in water using amphiphilic tetraphenylethene (TPE1, energy donor) and thienyl-diketopyrrolopyrrole (NDPP, energy acceptor). This hybrid NPs are uniform spherical, with size of approximately 120 nm. NDPP maintains bright fluorescence inside the hybrid NPs and acts as the reactive unit for hypochlorite in this FRET nanosystem. As a ratiometric fluorescent nanoprobe, the hybrid NPs shows high selectivity to hypochlorite with a detection limit calculated to be 105 nM, thanks to its stable particle size in hypochlorite sensing. Furthermore, the successful ratiometric fluorescent imaging of ClO− in HeLa cells demonstrates that our NPs can effectively pass through the cell membrane and recognize the ClO− in living cells.

Preparation of Calcipotriol Emulsion Using Bacterial Exopolysaccharides as Emulsifier for Percutaneous Treatment of Psoriasis Vulgaris.

An exopolysaccharides/calcipotriol (EPS/CPT) emulsion was prepared using bacterial EPS as emulsifier, sunflower oil as an oil phase and CPT as the loaded drug, and the effect of this emulsion on psoriasis vulgaris treatment was evaluated. An EPS composed of mannose (70.56%) and glucose (29.44%) was obtained from the marine mangrove bacteria Bacillus amyloliquefaciens ZWJ (Zhu Wenjing) strain. The EPS has significant emulsifying activity at the concentration of 1.5%. The prepared EPS/CPT emulsion has small and stable particle size, with a drug content of 0.00492%, and good spreading properties. The in vitro drug release results revealed that the emulsion showed a certain sustained release effect. In vitro and in vivo animal experiments show that the EPS/CPT emulsion can effectively treat psoriasis vulgaris by increasing the accumulation of CPT in psoriatic skin lesions and reducing the levels of inflammatory cells and inflammatory factors (TNF and IL6). Additionally, it has a certain effect on reducing the side effects associated with CPT. This study lays a foundation for the research of EPS in the topical application of medical materials and treatment of psoriasis.

Filtration Properties of a Two-Sided Irradiated Track-Etched Membrane with a Thickness Exceeding the Ion Range

Filtration properties of a new two-sided irradiated membrane with a thickness of 20 µm (exceeding the range of the incident ion), a pore diameter of 0.20 µm, and a pore density of 1.5 × 108 cm−2 have been studied in comparison with a one-sided irradiated 12-µm membrane having the same pore size and a somewhat higher pore density of 2.3 × 108 cm−2. An aqueous dispersion of a dye with a stable particle size distribution has been used in the experiments, with most of the particles being not larger than the pore size of the membranes. Close permeability values have been found for both membranes operating in the dead-end filtration mode, with the two-sided irradiated membrane being slightly better, and their close selective properties with some advantage of the one-sided irradiated membrane have been shown using dynamic light scattering and spectrophotometry techniques. For different dye dispersion concentrations, the mechanism of reduction in the productivity of the filtration process has been determined and differences in the limiting size of the rejected particles have been shown. It has been found that in the crossflow mode, the two-sided irradiated membrane has a certain advantage in permeability, whereas the one-sided irradiated membrane has higher rejection ability. In general, it has been concluded that the new two-sided irradiated membrane can be used in water treatment processes on a par with a one-sided irradiated membrane.

Ureido-modified carboxymethyl chitosan-graft-stearic acid polymeric nano-micelles as a targeted delivering carrier of clarithromycin for Helicobacter pylori: Preparation and in vitro evaluation.

The effect of antibiotics in the stomach for curing Helicobacter pylori infection is hampered by the adverse gastric environment and low bioavailability of the administered drugs. Concerning these challenges, a polymeric nano-micelle was developed. Initially, carboxymethyl chitosan (CMCS) was hydrophobically modified with stearic acid (SA), and the obtained CMCS-g-SA co-polymers was further conjugated with urea to acquire U-CMCS-g-SA co-polymers. Sphere-shaped nano-micelles (UCS-NMs) with the particle sizes of approximately 200nm were obtained with the U-CMCS-g-SA co-polymers. It was specified that this nano-micelle had no cell toxicity to AGS cells, and it could maintain a stable particle size for 6h in simulated gastric fluid and for 24h in 1×PBS. Attractively, the CMCS backbones granted this nano-micelle an excellent retention time in the stomach, almost 24h; meanwhile, the grafted ureido groups conferred effective targeting to H. pylori. This nano-micelle could load clarithromycin with high efficiency and exhibited slow release of this antibiotic in a slightly alkaline environment. In vitro inhibitory assay also indicated that a significantly enhanced anti-H. pylori activity was achieved by using this nano-micelle. This work demonstrated that the U-CMCS-g-SA nano-micelle is a proper carrier for targeted delivery of clarithromycin to H. pylori under the gastric mucus layer.

Preparation, optimization of intravenous ZL-004 nanosuspensions by the precipitation method, effect of particle size on in vivo pharmacokinetics and tissue distribution

Nanosuspension has been widely used to improve the bioavailability of poorly soluble drugs. ZL-004, a promising small molecular compound with the function of raising counts of white blood cells, was developed to nanosuspensions to solve the low solubility and bioavailability by the precipitation method. The effects of the important factors (THF/Water ratio, Tween-80, PEG 400) on the particle size were investigated by a central composite design. After freeze drying, with 6% sucrose as protective agent, a 399 ± 20 nm nanosuspension (NS-A) and a 208 ± 14 nm nanosuspension (NS-B) were obtained with good appearances, rapid redispersity, and stable particle sizes. The morphology and crystal forms were evaluated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). In vitro release test proved that the solubility and dissolution rate were improved by reducing the particle size. In vivo pharmacokinetic study and tissue distribution study in rats showed that particle size affected the pharmacokinetic behavior significantly by different accumulation in reticuloendothelial system (RES). NS-A with a larger particle size was captured and accumulated more in RES, achieving higher t1/2 and MRT; NS-B with a smaller particle size was captured and accumulated less in RES, achieving higher AUC and Cmax.

The Effect of Agglomeration Reduction on the Tribological Behavior of WS2 and MoS2 Nanoparticle Additives in the Boundary Lubrication Regime

This study investigates the impact of different surfactants and dispersion techniques on the friction and wear behavior of WS2 and MoS2 nanoparticles additives in a Polyalphaolefin (PAO) base oil under boundary lubrication conditions. The nanoparticles were dispersed using Oleic acid (OA) and Polyvinylpyrrolidone (PVP) to investigate their impact on particle agglomeration. The size distribution of the dispersed nanoparticles in PAO was measured by dynamic light scattering. The nanoparticles treated using PVP resulted in the most stable particle size. Friction studies showed that nanoparticle agglomeration reduction and the homogeneity of the suspension did not significantly impact the friction reduction behavior of the lubricant. Reciprocating wear experiments showed that, for our test conditions, both WS2 and MoS2 nano additives exhibited maximum wear depth reduction (45%) when using the PVP surface treatment compared to base oil. The wear results confirmed the significance of minimizing agglomeration and promoting high dispersion in promoting favorable wear resistance under boundary lubricant conditions. Analysis of the wear surfaces showed that a tribofilm formation was the primary wear reduction mechanism for WS2 particles treated by PVP while, in the case of MoS2 treated by PVP, the mechanism was load sharing via particles rolling and/or sliding at the interface.

Characterization of Fe2O3/Mn2O3 Oxygen Carrier for Chemical Looping Combustion Prepared by Dry Impregnation Method

Recently, bauxite waste was found as newly sourced of Fe-based oxygen carrier in chemical looping combustion (CLC) since it contains high Fe and capable to be used as oxygen carrier at low cost. This study focuses on synthesizing and characterizing the bauxite waste that found in Malaysia with Mn2O3 using dry impregnation method and study the feasibility of this bauxite waste as oxygen carrier. Results show the combination of bauxite waste – Mn2O3 at 900°C produces crystallite size 21 nm with the presence of Fe-Mn, stable Al2O3 and Ti elements that can improve the reactivity of Fe-Mn oxygen carrier. Moreover, Al2O3 that contains naturally in bauxite waste can acts as supported material for Fe-Mn oxygen carrier in order to increase performance in CLC process. Therefore, this powder was successfully synthesized using dry impregnation method at calcination temperature 900°C and fit to be tested in a fluidized bed reactor to simulate the CLC process since it has smaller and stable particle size.

Influence of milk protein concentrates with modified calcium content on enteral dairy beverage formulations: Storage stability

Control of calcium-mediated storage defects, such as age gelation and sedimentation, were evaluated in enteral high-protein dairy beverages during storage. To investigate the effects of reduced-calcium ingredients on storage stability, 2 batches each of milk protein concentrates (MPC) with 3 levels of calcium content were acquired [control, 20% calcium-reduced (MPC-20), and 30% calcium-reduced (MPC-30)]. Control and calcium-reduced MPC were used to formulate 8% (wt/wt) protein enteral dairy beverages. The formulation also consisted of other ingredients, such as gums, maltodextrin, potassium citrate, and sucrose. The pH-adjusted formulation was divided into 2 parts, one with 0.15% sodium hexametaphosphate (SHMP) and the other with 0% SHMP. The formulations were homogenized and retort sterilized at 121°C for 15 min. The retort-sterilized beverages were stored at room temperature for up to 90 d and particle size and apparent viscosity were measured on d 0, 7, 30, 60, and 90. Beverages formulated using control MPC with 0 and 0.15% SHMP exhibited sedimentation, causing a decrease in apparent viscosity by approximately 10 cP and clear phase separation by d 90. The MPC-20 beverages with 0% SHMP exhibited stable particle size and apparent viscosities during storage. In the presence of 0.15% SHMP, particle size increased rapidly by 40 nm on d 90, implying the start of progressive gelation. On the other hand, highest apparent viscosities leading to gelation were observed in MPC-30 beverages at both concentrations of SHMP studied. These results suggested that beverages formulated with MPC-20 and 0% SHMP would have better storage stability by maintaining lower apparent viscosities. Further reduction of calcium using MPC-30 resulted in rapid gelation of beverages during storage.

Redox Responsive Polymersomes for Enhanced Doxorubicin Delivery.

In the present investigation, the potential of a novel, self-assembled, biocompatible, and redox-sensitive copolymer system with disulfide bond was explored for doxorubicin (DOX) delivery through polymersome nanostructures of ∼120 nm. The polymer system was synthesized with less steps, providing a high yield of 86%. The developed polymersomes showed admirable biocompatibility with high dose tolerability in vitro and in vivo. The colloidal stability of DOX-loaded polymersomes depicted a stable and uniform particle size over a period of 72 h. The cellular internalization of polymersomes was assessed in HeLa and MDA-MB-231 cell lines, where enhanced cellular internalization was observed. The dose-dependent cytotoxicity was observed for DOX-loaded polymersomes by MTT cytotoxicity assay in the above cell lines. The tumor suppression studies were assessed in Ehrlich ascites tumor (EAT) carrying Swiss albino mice, where polymersomes exhibited a 7.16-fold reduction in tumor volume correlated with control and 5.39-fold higher tumor inhibition capacity compared to conventional chemotherapy (free DOX treatment). The developed polymersomes gave safer insights concerning DOX associated toxicities by histopathology and serum biochemistry analysis. Thus, results focus on the potential of redox responsive polymersomes for efficacious and improved DOX therapy with enhanced antitumor activity and insignificant cardiotoxicity which can be translated to clinical settings.