Influence of concentration, ionic strength and pH on zeta potential and mean hydrodynamic diameter of edible polysaccharide solutions envisaged for multinanolayered films production

Spontaneous Fusion of Core-Shell Nanocapsules with Oil Cores and Oppositely Charged Polysaccharide Shells

Polymer nanocapsules with hydrophobic cores are promising candidates for nanoreactors to carry out (bio)chemical reactions mimicking the performance of natural cellular systems. Their architecture allows reagents to be encapsulated in the cores enabling reactions to proceed in confined environments in a controlled, and efficient manner. Polysaccharide-shell oil-core nanocapsules are proposed here as facile mergeable nanoreactors. Spontaneous fusion of oppositely charged polysaccharide capsules is demonstrated for the first time. Such capsules are formed and easily loaded with reagents by nanoemulsification of an aqueous solution of hydrophobically modified polysaccharides (chitosan, hyaluronate) and oleic acid with dissolved desired hydrophobic compounds. Efficient fusion of the formed nanocapsules dispersed in an aqueous medium at optimized conditions (pH, ionic strength) is followed using fluorescence microscopy by labeling both their cores and shells with fluorescent dyes. As a proof of concept, a model fluorogenic synthesis is also realized by fusing the capsules containing separated reagents and the catalyst. The nanocapsules and fusion process developed here establish a platform for realization of versatile reactions in a confined environment including model studies on biologically relevant processes taking place in natural systems.

Modification of pea dietary fibre by superfine grinding assisted enzymatic modification: Structural, physicochemical, and functional properties

Using the optimal extraction conditions determined by response surface optimisation, the yield of soluble dietary fibre (SDF) modified by superfine grinding combined with enzymatic modification (SE-SDF) was significantly increased from 4.45 % ± 0.21 % (natural pea dietary fibre) to 16.24 % ± 0.09 %. To further analyse the modification mechanism, the effects of three modification methods-superfine grinding (S), enzymatic modification (E), and superfine grinding combined with enzymatic modification (SE)-on the structural, physicochemical, and functional properties of pea SDF were studied. Nuclear magnetic resonance spectroscopy results showed that all four SDFs had α- and β-glycosidic bonds. Fourier transform infrared spectroscopy and X-ray diffraction spectroscopy results showed that the crystal structure of SE-SDF was most severely damaged. The Congo red experimental results showed that none of the four SDFs had a triple-helical structure. Scanning electron microscopy showed that SE-SDF had a looser structure and an obvious honeycomb structure than other SDFs. Thermogravimetric analysis, particle size, and zeta potential results showed that SE-SDF had the highest thermal stability, smallest particle size, and excellent solution stability compared with the other samples. The hydration properties showed that SE-SDF had the best water solubility capacity and water-holding capacity. All three modification methods (S, E, and SE) enhanced the sodium cholate adsorption capacity, cholesterol adsorption capacity, cation exchange capacity, and nitrite ion adsorption capacity of pea SDF. Among them, the SE modification had the greatest effect. This study showed that superfine grinding combined with enzymatic modification can effectively improve the SDF content and the physicochemical and functional properties of pea dietary fibre, which gives pea dietary fibre great application potential in functional foods.

An in-depth investigation of molecular interaction in zeaxanthin/corn silk glycan complexes and its positive role in hypoglycemic activity

Glycans in corn silk could interact with co-existing small molecules during its absorption, digestion, and biological process. In order to understand the exact mechanism of action of zeaxanthin, it is critical to investigate the biomolecular interactions, which were necessary to form a glycan-small molecule complex and yet produce the bioactive effect. So far, the in-depth study of these natural interactions has not been fully elucidated. Here, we probed that the molecular interaction between zeaxanthin (ZEA) and glycans from corn silk (CSGs) was driven by enthalpy. More importantly, it was the first time found that CSGs can bind to lipid-soluble ZEA could be binded with CSGs. It was the first report on the thermostability of insulin structure and natural glycans. This study should facilitate our understanding of the interaction between lipid soluble molecules and glycans, and provide a more comprehensive understanding of the nutrient base in food.

Bovine serum albumin-modified 3D printed alginate dialdehyde-gelatin scaffolds incorporating polydopamine/SiO2-CaO nanoparticles for bone regeneration

Three-dimensional (3D) printing allows precise manufacturing of bone scaffolds for patient-specific applications and is one of the most recently developed and implemented technologies. In this study, bilayer and multimaterial alginate dialdehyde-gelatin (ADA-GEL) scaffolds incorporating polydopamine (PDA)/SiO2-CaO nanoparticle complexes were 3D printed using a pneumatic extrusion-based 3D printing technology and further modified on the surface with bovine serum albumin (BSA) for application in bone regeneration. The morphology, chemistry, and in vitro bioactivity of PDA/SiO2-CaO nanoparticle complexes were characterized (n = 3) and compared with those of mesoporous SiO2-CaO nanoparticles. Successful deposition of the PDA layer on the surface of the SiO2-CaO nanoparticles allowed better dispersion in a liquid medium and showed enhanced bioactivity. Rheological studies (n = 3) of ADA-GEL inks consisting of PDA/SiO2-CaO nanoparticle complexes showed results that may indicate better injectability and printability behavior compared to ADA-GEL inks incorporating unmodified nanoparticles. Microscopic observations of 3D printed scaffolds revealed that PDA/SiO2-CaO nanoparticle complexes introduced additional topography onto the surface of 3D printed scaffolds. Additionally, the modified scaffolds were mechanically stable and elastic, closely mimicking the properties of natural bone. Furthermore, protein-coated bilayer scaffolds displayed controllable absorption and biodegradation, enhanced bioactivity, MC3T3-E1 cell adhesion, proliferation, and higher alkaline phosphatase (ALP) activity (n = 3) compared to unmodified scaffolds. Consequently, the present results confirm that ADA-GEL scaffolds incorporating PDA/SiO2-CaO nanoparticle complexes modified with BSA offer a promising approach for bone regeneration applications.

"MD" method for the precise analysis of the O-acetyl-mannan structure and disclosure of the role in the conformational stability of insulin

Among the diversified glycan modifications, acylation is one of the most abundant. This modification could be responsible for many of the properties of glycans, such as structural stability and specificity for biological activity. To obtain better insight into the effects of acetylation of glycans on the structure and thermostability of insulin, it is critical to investigate glycans with a high degree of acetylation. An in-depth study of three functional glycans named acetyl-mannan from Dendrobium devonianum (DDAM) was conducted herein by efficient enzymatic depolymerization, and the effect of glycosidic bonds on acetylation modification sites was studied through a molecular dynamics (MD) method, as well as its positive effect on insulin secretion, glucose uptake, and the thermal stability of tertiary structures in vitro. Further study indicated that DDAMs play a hypoglycemic role by sparking the thermostability of the insulin conformation. The hypoglycemic activity displayed a positive correlation with the degree of acetylation in DDAMs. In this work, through the MD method, we confirmed the structure characteristics of DDAMs and provided accurate data support for the structure-activity relationship analysis. Thus, these findings demonstrated that DDAMs might be an exceptional leading compound for the stability of insulin drug.

The Influence of Initiators, Particle Size and Composition on the Electrokinetic Potential of N-(Isopropyl)acrylamide Derivatives

The aim of this study was to characterize and compare the zeta potential of particles sensitive to external thermal stimuli. Poly N-(isopropyl) acrylamide (PNIPA) was selected as the thermosensitive polymer with a volume phase transition temperature (VPTT) between 32 and 33 °C. The hydrodynamic diameter (DH) of the nanoparticles was measured by dynamic light scattering. Zeta potential (ZP) measurements were performed with the same instrument used for DH measurements. ZP measurements allow the prediction of the stability of colloidal systems in aqueous solutions. These measurements were combined with a pH study before and after the purification process of the particles. The ZP was measured to determine the electrostatic interactions between the particles, which can lead to particle aggregation and decrease their colloidal stability. The effect of the composition of the synthesized particles on the ZP was assessed. One of the most important factors influencing ZP is pH, especially in aqueous solutions. The initiator did not significantly affect the DH of the particles, but it did significantly affect the ZP. The synthesized particles were subjected to a visible radiation absorption study in the selected temperature range to determine the VPTT.

Effect of subcritical water temperature on the structure, antioxidant activity and immune activity of polysaccharides from Glycyrrhiza inflata Batalin

In this study, the polysaccharide from Glycyrrhiza inflata Batalin extracted by hot water (HW-GP) was further physically modified with subcritical water to obtain novel polysaccharides (SW-GP). Comparative analysis was conducted to examine the disparities in conformation and bioactivity between HW-GP and SW-GP, aiming to precisely regulate the structure of the polysaccharides and enhance their bioactivity by controlling subcritical water temperature. The results showed that, compared with HW-GP, subcritical water modification (100-160 °C) not only significantly reduced the molecular weight of polysaccharides (from 5.586 × 105 g/mol to 1.484 × 105 g/mol), but also modulated the intermolecular interaction forces, which maintain the conformation of the polysaccharides, including electrostatic and hydrophobic interactions, thereby dynamically transforming the polysaccharide chain conformation from triple helix to random coil, and the strength of the chain conformation shifted from rigid to flexible. In addition, the modification of the SW-GP structure by subcritical water also enhanced its biological activity. SW-GP (140 °C) with low molecular weight and semi-rigid triple helix conformation showed the best scavenging effect on the DPPH, ABTS, and hydroxyl radicals, and exhibited excellent antioxidant activity. SW-GP (130 °C) with medium molecular weight and semi-rigid triple helix conformation significantly promoted the proliferation and phagocytosis of RAW264.7 cells, as well as increased the release levels of NO, TNF-α, IL-6, and IL-1β, and the immunomodulatory activity was much higher than that of other polysaccharides. These findings confirmed the feasibility of using subcritical water temperature as a regulatory feature for the structure and bioactivity of glycyrrhiza polysaccharides, which may have reference significance for the modification of polysaccharides with heightened bioactivity.

Comparative study on chain conformations, physicochemical and rheological properties of three acidic polysaccharides from Opuntia dillenii Haw. fruits

In this study, three acidic polysaccharides (OFPP-1, OFPP-2 and OFPP-3) were isolated from the pulps of Opuntia dillenii Haw. fruits, and their chain conformations, physicochemical and rheological properties were investigated. The molecular weight and conformational parameters (Mw, Mn, Mz, Rg and Rh) of OFPPs in 0.1 M NaNO3 solution were detected by HPSEC-MALLS-RI. In addition, based on the parameters ρ and v, it was concluded that these three polysaccharide chains exhibited sphere-like conformation in 0.1 M NaNO3 solution, which was consistent with AFM and TEM observations. Furthermore, the Congo Red experiment showed that OFPP-2 had a triple-helix structure, which may be conducive to its biological activity. This study also found that OFPPs were semi-crystalline structures with high thermal and pH stability. The rheological analyses indicated that the apparent viscosity of OFPPs solutions exhibited concentration-, temperature-, and pH-dependence, and the viscoelasticity of them was affected by molecular characteristics and concentration. The results of this study are helpful to elucidate the structure-activity relationship of OFPPs. Moreover, this study can provide theoretical reference for the application of OFPPs as bioactive ingredients or functional materials in the food, pharmaceutical and cosmetic industries and the development and utilization of the O. dillenii Haw. fruits resource.

Comparative Study on the Impact of Different Extraction Technologies on Structural Characteristics, Physicochemical Properties, and Biological Activities of Polysaccharides from Seedless Chestnut Rose (Rosa sterilis) Fruit

Seedless chestnut rose (Rosa sterilis S. D. Shi, RS) is a fresh type of R. roxburghii Tratt with copious functional components in its fruit. Polysaccharides are recognized as one of the vital bioactive compounds in RS fruits, but their antioxidant and hypoglycemic properties have not been extensively explored. Hence, in this study, accelerated solvent extraction (RSP-W), citric acid (RSP-C), 5% sodium hydroxide/0.05% sodium borohydride (RSP-A), and 0.9% sodium chloride (RSP-S) solution extraction were individually utilized to obtain RS fruit polysaccharides. The physicochemical properties, structural characteristics, and biological activities were then compared. Results indicated that extraction methods had significant influences on the extraction yield, uronic acid content, monosaccharide composition, molecular weight, particle size, thermal stability, triple-helical structure, and surface morphology of RSPs apart from the major linkage bands and crystalline characteristics. The bioactivity tests showed that the RSP-S, which had the greatest amount of uronic acid and a comparatively lower molecular weight, exhibited more potent antioxidant and α-glucosidase inhibitory property. Furthermore, all RSPs inhibited α-glucosidase through a mixed-type manner and quenched their fluorescence predominantly via a static quenching mechanism, with RSP-S showing the highest binding efficiency. Our findings provide a theoretical basis for utilizing RSPs as functional ingredients in food industries.

Synergistic roles of oxidation and self-aggregation in efficient ultrafiltration membrane fouling alleviation using a flow-through Sb-SnO2 anode during wastewater reclamation

The application of ultrafiltration (UF) in wastewater reclamation alleviates the demand for limited water supplies. However, the membrane fouling caused by the effluent organic matter (EfOM) becomes a major obstacle for UF application. In this study, a pre-oxidation strategy for UF using a Sb-SnO2 (ATO) anode in flow-through mode was proposed with the hopes to improve the performance of UF during wastewater reclamation. The results indicated that this flow-through ATO (FA) anode significantly outperformed a boron-doped diamond (BDD) anode in terms of EfOM degradation and membrane fouling control. It is noteworthy that apart from oxidation, the self-aggregation behavior of foulants was also involved in the mechanisms of membrane fouling mitigation. On the one hand, FA pre-oxidation relieved the burden of membrane fouling by decomposing the macromolecular EfOM into small molecular organic matter, and even mineralizing it. The effective destruction of unsaturated EfOM by FA pre-oxidation made a remarkable contribution to fouling mitigation due to the strong correlation between the total fouling index and UV254. On the other hand, the surface morphology of membrane and interface properties of foulants revealed the self-aggregation behavior of foulants. FA pre-oxidation made the foulants aggregate spontaneously and reduced the potential of forming a dense cake layer on the membrane surface, which was conductive for water permeation. Overall, FA pre-oxidation proved to be a feasible and chemical-free option for UF pretreatment to simultaneously produce high-quality reused water and alleviate membrane fouling during wastewater reclamation.

Extraction and characterization of polysaccharides from Schisandra sphenanthera fruit by Lactobacillus plantarum CICC 23121-assisted fermentation

Improving the yield of polysaccharides extracted from Schisandra sphenanthera is a major challenge in traditional Chinese medicinal plants. In this study, we investigated the potential of Lactobacillus plantarum CICC 23121-assisted fermentation as an extraction tool for S. sphenanthera polysaccharides (SSP). We observed that 11.12 ± 0.28 % of polysaccharides were extracted from S. sphenanthera using strain CICC 23121 -assisted fermentation (F-SSP), which was 53.38 % higher than that using hot water extraction (NF-SSP). The optimized parameters were a fermentation time of 15.5 h, substrate concentration of 4 %, and inoculum size of 3 %. Lactic acid produced by strain CICC 23121 increased the release of intracellular polysaccharides by breaking down cell walls. Compared to NF-SSP, F-SSP contained higher and lower total carbohydrate and protein contents, respectively, and its monosaccharide composition was the same as that of NF-SSP; however, their distributions were different. F-SSP had a higher molecular weight, better aqueous stability, and looser surface morphology, and strain CICC 23121-assisted fermentation did not change the molecular structure of SSP. Both NF-SSP and F-SSP showed the potential to regulate human intestinal microflora. Our findings revealed that strain CICC 23121-assisted fermentation is an efficient method for extracting S. sphenanthera polysaccharides without affecting their physicochemical and bioactive properties.

Imaging and Non-imaging Analytical Techniques Used for Drug Nanosizing and their Patents: An Overview

BACKGROUND

Nanosizing is widely recognized as an effective technique for improving the solubility, dissolution rate, onset of action, and bioavailability of poorly water-soluble drugs. To control the execution and behavior of the output product, more advanced and valuable analytical techniques are required.

OBJECTIVE

The primary intent of this review manuscript was to furnish the understanding of imaging and non-imaging techniques related to nanosizing analysis by focusing on related patents. In addition, the study also aimed to collect and illustrate the information on various classical (laser diffractometry, photon correlation spectroscopy, zeta potential, laser Doppler electrophoresis, X-ray diffractometry, differential scanning calorimeter, scanning electron microscopy, transmission electron microscopy), new, and advanced analytical techniques (improved dynamic light scattering method, Brunauer-Emmett- Teller method, ultrasonic attenuation, biosensor), as well as commercial techniques, like inductively coupled plasma mass spectroscopy, aerodynamic particle sizer, scanning mobility particle sizer, and matrix- assisted laser desorption/ionization mass spectroscopy, which all relate to nano-sized particles.

METHODS

The present manuscript has taken a fresh look at the various aspects of the analytical techniques utilized in the process of nanosizing, and has achieved this through the analysis of a wide range of peer-reviewed literature. All summarized literature studies provide the information that can meet the basic needs of nanotechnology.

RESULTS

A variety of analytical techniques related to the nanosizing process have already been established and have great potential to weed out several issues. However, the current scenarios require more relevant, accurate, and advanced analytical techniques that can minimize the time and deviations associated with different instrumental and process parameters. To meet this requirement, some new and more advanced analytical techniques have recently been discovered, like ultrasonic attenuation technique, BET technique, biosensors, etc. Conclusion: The present overview certifies the significance of different analytical techniques utilized in the nanosizing process. The overview also provides information on various patents related to sophisticated analytical tools that can meet the needs of such an advanced field. The data show that the nanotechnology field will flourish in the coming future.

Structural and chemical insights into the prebiotic property of hemicellulosic polysaccharide from Santalum album L

Hemicellulose was extracted by alkali treatment of de-pectinated cell wall material of Santalum album L. (sandalwood) suspension culture cells. The physicochemical properties and prebiotic activities of a purified major fraction of Hemicellulose-B, termed as HB-I, were investigated. GC analysis of hydrolyzed and derivatized HB-I showed the presence of arabinose (~64 %), galactose (~16 %) and glucose (~16 %) as major monosaccharide units along with minor amount of rhamnose. Methylation and NMR studies on the purified polysaccharide revealed the presence of 6-β-d-Glcp, β-d-Galp, 3,5-α-l-Araf, α-l-Araf, 5-α-l-Araf, 2,3-α-l-Araf and, α-l-Rhap residues, from which a proposed structure of repeating units was established. The growth of probiotic Lactobacillus spp. strains L. acidophilus, L. casei, L. plantarum and L. rhamnosus was promoted while that of Escherichia coli was suppressed significantly in presence of HB-I. Our results highlight valorization of sandalwood biomass and explore the role of mixed α, β-linked heteroglycan as a potential prebiotic molecule thus indicating the possibility of development of low-cost bioprocesses for production of functional food ingredients.

Properties of Active Levan-Bitter Vetch Protein Films for Potential Use in Food Packaging Applications

ζ-potential and Z-average were determined on film-forming solutions of bitter vetch-levan-based films prepared at different ratios in the absence and presence of glycerol as a plasticizer. The casting method was used to obtain manageable films. The results revealed that levan increases the elongation at break of bitter vetch protein films and reduces the tensile strength. The optimal result was obtained through the film that was prepared with the ratio of 50% bitter vetch proteins and 50% levan, in terms of mechanical properties. The surfaces of the prepared films appeared to be more compact and smooth. On increasing the glycerol concentration in the bitter vetch protein-levan films, the oxygen and water vapor permeability increased compared to the control (P < 0.05). Based on the overall results, the reinforcement of bitter vetch proteins with levan at a ratio of 1:1 represents optimal film properties in the presence of a low concentration of glycerol. The proposed film is suggested as an innovative packaging system for beef meat to preserve its quality over time.

Multivariable analysis of egg white protein-chitosan interaction: Influence of pH, temperature, biopolymers ratio, and ionic concentration

The influence of pH, temperature, biopolymer ratio, total concentration, and ionic concentration on the interaction between egg white protein (EWP) and chitosan (CS) was investigated through turbidity, zeta potential, and state diagram in our research. In addition, phase behavior was observed under various conditions. The turbidity of EWP remained low (turbidity < 0.03) and basically unchanged at a wide range of pH (4.0-8.0), while the turbidity of CS was slightly higher (turbidity < 0.2) after pH 7.0 than before. Moreover, under the same conditions, a sharply rising peak pattern was observed for the complex between EWP and CS. The maximum turbidity value was observed at 55 °C, and the temperature had a mild effect on turbidity. The optimum EWP to CS ratio was found to be 12:1 based on the turbidity curves and state diagrams influenced by different biopolymer mixing ratios. With the enhanced concentrations of total biopolymer, the maximum turbidity rose insignificantly above 0.1%.

Thiolated chitosan hydrogel-embedded niosomes: A promising crocin delivery system toward the management of aphthous stomatitis

Aphthous stomatitis is a common inflammatory oral disease with challenging management. Crocin is a natural carotenoid that has shown great anti-inflammatory properties. The aim of this study was to develop thiolated chitosan (TCS)-based hydrogels containing niosomes to serve as a mucoadhesive crocin delivery system for aphthous stomatitis. Crocin-loaded niosomes were prepared and the impact of surfactant type, cholesterol content, and lipid to drug ratio on the characteristics of niosomes was evaluated. TCS was synthesized and the success of thiolation was investigated. The optimum niosomal formulation was loaded into the hydrogel and the hybrid system was characterized regarding the morphology, mucoadhesive properties, viscosity, chemical structure, in vitro drug release, and in vivo efficacy. The optimized niosome formulation showed 77% crocin entrapment, a particle diameter of 59 nm, and a zeta potential of -18 mV. The niosome-containing hydrogel exhibited pseudoplastic rheological behavior, mucoadhesive properties, suitable swelling, and sustained release of crocin. In vivo study revealed that the niosome-containing hydrogel improved ulcer healing and decreased the expression of tumor necrosis factor-alpha (TNF-α) and p53 while increasing the expression of vascular endothelial growth factor (VEGF) and alpha-smooth muscle actin (α-SMA). Collectively, TCS hydrogel-embedded crocin-loaded niosomes is a promising therapeutic option for aphthous stomatitis. CHEMICAL COMPOUNDS STUDIED IN THIS ARTICLE: Crocin (PubChem CID: 5281233) Chitosan (PubChem CID: 71853) Thioglycolic acid (PubChem CID: 1133) 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (PubChem CID: 2723939) 5,5'-dithiobis (2-nitrobenzoic acid) (PubChem CID: 6254) Cholesterol (PubChem CID: 5997).

Interaction between roxarsone, an organic arsenic compound, with humic substances in the soil simulating environmental conditions

In environmental systems, the soil is a principal route of contamination by various potentially toxic species. Roxarsone (RX) is an arsenic (V) organic compound used to treat parasitic diseases and as an additive for animal fattening. When the animal excretes RX, the residues may lead to environmental contamination. Due to their physicochemical properties, the soil's humic substances (HS) are important in species distribution in the environment and are involved in various specific interaction/adsorption processes. Since RX, an arsenic (V) compound, is considered an emerging contaminant, its interaction with HS was evaluated in simulated environmental conditions. The HS-RX interaction was analyzed by monitoring intrinsic HS fluorescence intensity variations caused by complexation with RX, forming non-fluorescent supramolecular complexes that yielded a binding constant Kb (on the order of 103). The HS-RX interaction occurred through static quenching due to complex formation in the ground state, which was confirmed by spectrophotometry. The process was spontaneous (ΔG < 0), and the predominant interaction forces were van der Waals and hydrogen bonding (ΔH < 0 and ΔS < 0), with an electrostatic component evidenced by the influence of ionic strength in the interaction process. Structural changes in the HS were verified by synchronized and 3D fluorescence, with higher variation in the region referring to the protein-like fraction. In addition, metal ions (except ions Cu(II)) favored HS-RX interaction. When interacting with HS, the RX epitope was suggested by 1H NMR, which indicated that the entire molecule interacts with the superstructure. An enzyme inhibition assay verified the ability to reduce the alkaline phosphatase activity of free and complexed RX (RX-HS). Finally, this work revealed the main parameters associated with HS and RX interaction in simulated environmental conditions, thus, providing data that may help our understanding of the dynamics of organic arsenic-influenced soils.

Oxidized pullulan exhibits potent antibacterial activity against S. aureus by disrupting its membrane integrity

The capability of bacteria to withstand the misuse of antibiotics leads to the generation of multi-drug resistant strains, posing a new challenge to curb wound infections. The biological macromolecules, due to their biocompatibility, biodegradability, and antimicrobial properties, have been explored for a variety of antimicrobial and therapeutic purposes. This work reports that a single-step oxidation of pullulan polymer leads to the formation of oxidized pullulan (o-pullulan), which shows striking antibacterial and antibiofilm activities against the Gram-positive bacteria, Staphylococcus aureus, implicated in wound-related infections. Oxidation of pullulan generates 28 % aldehyde groups (3.462 mmol/g) which exerted 97 % bactericidal activity against S. aureus by targeting cell wall-associated membrane protein SpA (Staphylococcal protein A). The molecular docking, gene silencing, and fluorescence quenching studies revealed a direct binding of o-pullulan with the B and C domains of SpA, which alters the membrane potential and inhibits Ca2+-Mg2+-ATPase pumps. O-pullulan also exhibited scavenging activity against intracellular reactive oxygen species (ROS), and non-immunotoxic activity and was found to be non-toxic to mammalian cells. Thus, o-pullulan shows great promise as an antimicrobial polymer against S. aureus for chronic wound management.

Synthesis and Structural Characterization of Selenium Nanoparticles-Bacillus sp. MKUST-01 Exopolysaccharide (SeNPs-EPS) Conjugate for Biomedical Applications

Exopolysaccharides (EPS) are exogenous microbial metabolites generated predominantly during the development of bacteria. They have several biological potentials, including antibacterial, antioxidant, and anticancer actions. Polysaccharide-coated nanoparticles have high biological activity and are used in treatments and diagnostics. In this research, selenium nanoparticles (SeNPs) are synthesized and conjugated with bacterial (Bacillus sp. MKUST-01) exopolysaccharide (EPS). Initially, the creation of SeNPs conjugates was verified through UV-Vis spectral examination, which exhibited a prominent peak at 264 nm. Additionally, X-ray diffraction (XRD) analysis further substantiated the existence of crystalline Se, as evidenced by a robust reflection at 29.78°. Another reflection observed at 23.76° indicated the presence of carbon originating from the EPS. Fourier transform infrared spectroscopy (FT-IR) analysis of the EPS capped with SeNPs displayed characteristic peaks at 3425 cm-1, 2926 cm-1, 1639 cm-1, and 1411 cm-1, corresponding to the presence of O-H, C-H, C=O, and COO-groups. The SeNPs themselves were found to possess elongated rod-shaped structures with lengths ranging from 250 to 550 nm and a diameter of less than 70 nm, as confirmed using scanning electron microscopy and particle size analysis. In contrast to the SeNPs, the SeNPs-EPS conjugates showed no hemolytic activity. The overall antioxidant activity of SeNPs-EPS conjugates outperformed 20% higher than SeNPs and EPS. Additionally, experimental observations involving gnotobiotic Artemia nauplii experiments were also recorded, such as the supplementation of EPS and SeNPs-EPS conjugates corresponding to enhanced growth and increased survival rates compared to Artemia nauplii fed with SeNPs and a microalgal diet.

Effect of honeysuckle leaf extract on the physicochemical properties of carboxymethyl konjac glucomannan/konjac glucomannan/gelatin composite edible film

Honeysuckle leaves are rich in bioactive ingredients, but often considered as agro-wastes. In this study, honeysuckle leaf extract (HLE) was added to the carboxymethyl konjac glucomannan/konjac glucomannan/gelatin composite edible film (CMKH). Compared to films without HLE addition (CMK), the water vapor barrier properties of CMKH slightly decreased, but the transmittance of the CMKH films in UV region (200-400 nm) as low as zero. The elongation at break of CMKH film was 1.39 ∼ 1.5 fold higher than those of CMK films. The DPPH and ABTS scavenging activity of CMKH-Ⅱ was 85.75% and 90.93%, respectively, which is similar to the equivalent content of Vc. The inhibition rate of CMKH-Ⅰ and CMKH-Ⅱ against Escherichia coli and Listeria monocytogenes were close to 90%, and the inhibition rate against Staphylococcus aureus were up to 96%. The results emphasized that the composite film containing 25% (v/v) HLE has potential application value in food preservation.

Replacement of polyethylene oxide by peach gum to produce an active film using Litsea cubeba essential oil and its application in beef

This study evaluated the effects of adding various concentrations (0 %, 1 %, 2 %, and 3 %) of peach gum (PG) to films made from polyethylene oxide (PEO) combined with Litsea cubeba essential oil (LCEO) to be utilized as active packaging for food in the future. The findings showed that the film containing PG 2 % concentration had the best physic-mechanical properties. In films made with PG, the glass transition temperature was significantly improved. Combining PG and PEO resulted in films that were brighter in color, had lower WVP values, and had the lowest water activity. Furthermore, XRD demonstrated that PG additions were compatible with the film of PEO blended with LCEO. The PG films formulated with PG presented high antioxidant and antibacterial activity against Staphylococcus aureus and E. coli. Wrapping beef with P2G2 film led to maintaining its quality with suitable levels of pH, TBARS, and TVB-N. This also decreased the number of E. coli and S. aureus in beef throughout the storage period. The results indicate that adding PG to PEO films enhances their suitability for food preservation.

Quantitative Assessment of Interfacial Interactions Governing Ultrafiltration Membrane Fouling by the Mixture of Silica Nanoparticles (SiO2 NPs) and Natural Organic Matter (NOM): Effects of Solution Chemistry

Mixtures of silica nanoparticles (SiO₂ NPs) and natural organic matter (NOM) are ubiquitous in natural aquatic environments and pose risks to organisms. Ultrafiltration (UF) membranes can effectively remove SiO₂ NP-NOM mixtures. However, the corresponding membrane fouling mechanisms, particularly under different solution conditions, have not yet been studied. In this work, the effect of solution chemistry on polyethersulfone (PES) UF membrane fouling caused by a SiO₂ NP-NOM mixture was investigated at different pH levels, ionic strengths, and calcium concentrations. The corresponding membrane fouling mechanisms, i.e., Lifshitz-van der Waals (LW), electrostatic (EL), and acid-base (AB) interactions, were quantitatively evaluated using the extended Derjaguin-Landau-Verwey-Overbeek (xDLVO) theory. It was found that the extent of membrane fouling increased with decreasing pH, increasing ionic strength, and increasing calcium concentration. The attractive AB interaction between the clean/fouled membrane and foulant was the major fouling mechanism in both the initial adhesion and later cohesion stages, while the attractive LW and repulsive EL interactions were less important. The change of fouling potential with solution chemistry was negatively correlated with the calculated interaction energy, indicating that the UF membrane fouling behavior under different solution conditions can be effectively explained and predicted using the xDLVO theory.

Advanced structural characterization and in vitro fermentation prebiotic properties of cell wall polysaccharide from Kluyveromyces marxianus

Through previous study, the three yeast α-mannans (MPS) from various sources of Kluyveromyces marxianus (LZ-MPS, MC-MPS, and G-MPS) were preliminarily characterized. In this study, the advanced structural characterization and the in vitro human fecal fermentation behavior of the three MPS were investigated. According to the results of this study, the polysaccharide molecules of the three MPS were aggregated in solution, supporting their branched chain structure. After in vitro fermentation, the molecular weight and pH of fermentation broth decreased significantly, indicating that the three MPS could be utilized by human gut microbiota. Meanwhile, the production of total short-chain fatty acids (SCFAs) of the three MPS was promoted, especially the production of propionic acid was 45.55, 38.23, and 38.87 mM, respectively. In particular, the three MPS have the ability to alter the composition of human gut microbiota, especially to promote the proliferation of Bacteroidetes, suggesting that the bioactivities of the three MPS can be significantly influenced by intestine Bacteroidetes. In terms of metabolism, all MPS can promote cofactors, vitamins, amino acid metabolism, and glycan biosynthesis and metabolism of bacteria. In consequence, the three MPS were confirmed to regulate the human gut microbiota, increase the level of SCFAs, promote the metabolisms of bacteria on amino acid and glycan, and improve the intestinal health.

Tremella fuciform Polysaccharides: Extraction, Physicochemical, and Emulsion Properties at Different pHs

The chemical composition, macromolecular characteristics, and structure of four types of Tremella fuciform polysaccharides (TPS) were analyzed, including one TPS that was extracted in the laboratory (L-TPS) and three commercial TPS. The effects of pH on the properties of TPS emulsions were investigated by analyzing their zeta potential, particle size, apparent viscosity, and stability. The results showed that L-TPS presented a higher percentage content of protein (2.33%) than commercial TPS (0.73–0.87%), and a lower molecular mass (17.54 × 106 g/mol). Thus, L-TPS exhibited the best emulsifying activity but gave poor emulsion stability. The droplet sizes and apparent viscosity of commercial TPS-stabilized emulsions were larger or higher in acidic environments. At pH 2, the apparent viscosity was the lowest for L-TPS. Commercial TPS emulsions were most stable at pH 6, while the L-TPS-stabilized emulsion was most stable at pH 2. The obtained results revealed that the emulsifying properties of TPS varied and the effects of pH on emulsion characteristics differed, as determined from the molecular mass, macromolecular characteristics, and structure. This research is useful for expanding the application of TPS as a novel food ingredient in emulsions.

Segregative phase separation of gelatin and tragacanth gum solution and Mickering stabilization of their water-in-water emulsion with microgel particles prepared by complex coacervation

This study aimed to investigate the segregative interaction of gelatin (G) and tragacanth gum (TG) and the stabilization of their water-in-water (W/W) emulsion by G-TG complex coacervate particles. Segregation was studied at different pHs, ionic strengths and biopolymer concentrations. Results showed that incompatibility was affected by increasing the biopolymer concentrations. So, three reigns were demonstrated in the phase diagram of the salt-free samples. NaCl significantly changed the phase behavior via enhancement of self-association of polysaccharide and changing solvent quality due to the charge screening effect of ions. The W/W emulsion prepared from these two biopolymers and stabilized with G-TG complex particles was stable for at least one week. The microgel particles improved emulsion stability by adsorption to the interface and creating a physical barrier. A fibrous and network-like structure of the G-TG microgels was observed by scanning electron microscopy images suggesting the Mickering emulsion stabilization mechanism. It was confirmed that the bridging flocculation between the microgel polymers led to phase separation after the stability period. Biopolymer incompatibility investigation is a useful tool to obtain beneficial knowledge for preparation new food formulation, especially no contain oil emulsions for low- calorie diets.

Anthocyanin-Rich Jamun (Syzygium cumini L.) Pulp Transported on Protein-Coated Ionic Gelation Microparticles of Calcium Alginate: Production and Morphological Characteristics

Jamun (Syzygium cumini L.) is a fruit rich in anthocyanins, an important group of natural pigments, with color ranging from red to blue, soluble in water, highly antioxidant. Despite its great potential for use as a natural dye, its application is a challenge, due to the instability of these compounds in the environmental conditions of processing and storage commonly used by the food industry. Therefore, this study evaluated the microencapsulation of anthocyanin-rich jamun pulp by ionic gelation (IG) and its protein-coating by electrostatic interaction (PC). The effect of the ratio of sodium alginate solids and jamun pulp (1:0.40 to 1:2, w/w) and the concentration of gelatin coating solution (0% to 10%, w/w) on the morphology, water and total protein content and anthocyanins content in the microparticles were evaluated. Visually, the IG particles showed color tones ranging from reddish to purplish, which became less intense and opaque after being submitted to the gelatin coating process. Microscopic images demonstrated that microparticles formed had an irregular and heterogeneous shape with disorganized gel network formation is due to the presence of solid structures of jamun pulp, observed within the microparticles. The greater the concentration of gelatin in the coating solution, the greater the protein adsorption for the formation of the protective layer, ranging from 21.82 ± 0.72% (T1) to 55.87 ± 4.23% (T6). Protein adsorption on the GI resulted in a decrease in moisture content (ranging from 87.04 ± 0.22 to 97.06 ± 0.12%) and anthocyanins contents (ranging from 5.84 ± 0.62 to 0.78 ± 0.14%) in the PC microparticles.

Functionalized silica nanoparticles coupled with nanoporous membrane for efficient ionic current rectification

In the last few decades, tremendous effort has been dedicated to mimicking the efficient ionic current rectification (ICR) of biological nanopores. Nanoporous membranes and singular nanopores with ICR functionality have been fabricated using advanced, yet costly technologies. We herein demonstrate that a simple, novel, and robust ICR platform can be constructed using 80 nm silica nanoparticles and a piece of 15 nm track-etched polycarbonate membrane. Efficient ICR can be obtained when voltages of different polarities are applied across the membrane, due to the asymmetric electrophoretic migration of silica nanoparticles whose surfaces are modified with different functional groups. The effect of pore size, ionic strength, pH, voltage magnitude, and density of silica nanoparticles on the efficiency of the ICR system has been systematically investigated in this report. Our results clearly show that smaller pore, lower ionic strength, appropriate pH value, higher electrical field strength, lower density of silica nanoparticles can generally enhance the efficiency of the ICR system. The principles of this new ICR system may find many potential applications in controllable drug delivery, energy storage and water purification.

All-Aqueous Freeform Fabrication of Perfusable Self-Standing Soft Compartments

Compartmentalized structures obtained in all-aqueous settings have shown promising properties as cell encapsulation devices, as well as reactors for trans-membrane chemical reactions. While most approaches focus on the preparation of spherical devices, advances on the production of complex architectures have been enabled by the interfacial stability conferred by emulsion systems, namely mild aqueous two-phase systems (ATPS), or non-equilibrated analogues. However, the application of non-spherical structures has mostly been reported while keeping the fabricated materials at a stable interface, limiting the free-standing character, mobility and transposition of the obtained structures to different setups. Here, the fabrication of self-standing, malleable and perfusable tubular systems through all-aqueous interfacial assembly is shown, culminating in the preparation of independent objects with stability and homogeneity after disruption of the polymer-based aqueous separating system. Those hollow structures can be fabricated with a variety of widths, and rapidly printed as long structures at flow rates of 15 mm s^-1 . The materials are used as compartments for cell culture, showcasing high cytocompatibility, and can be tailored to promote cell adhesion. Such structures may find application in fields that benefit from freeform tubular structures, including the biomedical field with, for example, cell encapsulation, and benchtop preparation of microfluidic devices.

Preparation and characterization of Sargassum pallidum polysaccharide nanoparticles with enhanced antioxidant activity and adsorption capacity

Sargassum pallidum polysaccharide nanoparticle (nSPP-30) was prepared via antisolvent precipitation method and the preparation conditions were optimized. The effects of nanocrystallization on the structure and biological activities of S. pallidum polysaccharide were investigated. Under the optimal preparation condition, the average particle size, polydispersity index (PDI), and ξ-potential of nSPP-30 were 229.63 nm, 0.407, and -28.43 mV, respectively. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analyses indicated that nanocrystallization did not change primary and crystal structures of S. pallidum polysaccharide. However, nanocrystallization could improve the swelling, thermodynamic, and antioxidant properties of S. pallidum polysaccharide. In addition, the thymol adsorption capacity of nSPP-30 was enhanced as compared to the corresponding polysaccharide. These results suggest that nSPP-30 can be developed as a potential antioxidant or natural nano-carrier to encapsulate thymol for practical applications.

Stability Phenomena Associated with the Development of Polymer-Based Nanopesticides

Pesticides have been used in agricultural activity for decades because they represent the first defense against pathogens, harmful insects, and parasitic weeds. Conventional pesticides are commonly employed at high dosages to prevent their loss and degradation, guaranteeing effectiveness; however, this results in a large waste of resources and significant environmental pollution. In this regard, the search for biocompatible, biodegradable, and responsive materials has received greater attention in the last years to achieve the obtention of an efficient and green pesticide formulation. Nanotechnology is a useful tool to design and develop “nanopesticides” that limit pest degradation and ensure a controlled release using a lower concentration than the conventional methods. Besides different types of nanoparticles, polymeric nanocarriers represent the most promising group of nanomaterials to improve the agrochemicals’ sustainability due to polymers’ intrinsic properties. Polymeric nanoparticles are biocompatible, biodegradable, and suitable for chemical surface modification, making them attractive for pesticide delivery. This review summarizes the current use of synthetic and natural polymer-based nanopesticides, discussing their characteristics and their most common design shapes. Furthermore, we approached the instability phenomena in polymer-based nanopesticides and strategies to avoid it. Finally, we discussed the environmental risks and future challenges of polymeric nanopesticides to present a comprehensive analysis of this type of nanosystem.

Improved protective and controlled releasing effect of fish oil microcapsules with rice bran protein fibrils and xanthan gum as wall materials

This study aimed to prepare fish oil microcapsules by freeze-drying an emulsion co-stabilized by rice bran protein fibrils (RBPFs) and xanthan gum (XG) to improve the oxidation stability and controlled release effect. Emulsions stabilized either solely by RBPFs or unfibrillated rice bran protein (RBP) or by a combination of RBP and XG were also fabricated as microcapsule templates for comparison. The rheological properties, particle size, and zeta potential of the emulsions were examined. In addition, the characteristics of the fish oil microcapsules such as surface oil content, encapsulation efficiency, water activity, moisture content, morphological structure, oxidation stability, and digestive performance were also assessed. The rheological properties revealed that the addition of XG increased the storage modulus of the emulsion and reduced the loss modulus and apparent viscosity. At shear rates of 0-100 s^-1, the fish oil emulsion did not exhibit any gel properties or shear thinning. Fibrillation increased the particle size of the fish oil emulsion, whereas adding XG reduced the droplet size. The combination of RBP fibrillation and XG addition provided the highest encapsulation efficiency for fish oil. Fibrillation reduced the water activity and moisture content of the fish oil microcapsules. The anisotropy of the fibrils and the high viscosity of XG produced a layer of wrapping on the continuous heterogeneous surface of the freeze-dried powder particles. RBPF/XG microcapsules stored at 45 °C for 1 month had the lowest peroxide value and thiobarbituric acid value, the lowest surface oil content, and the lightest yellowness. These results suggest that the combination of RBPFs and XG provides better encapsulation and protective effects for fish oil microcapsules. Upon simulated digestion, the microcapsules containing XG and RBPFs exhibited a more favorable controlled release of free fatty acids. These findings indicate that microcapsules formed from emulsions co-stabilized by XG and RBPFs are suitable for encapsulating fish oil in functional foods.

Mechanochemical Preparation, Characterization and Biological Activity of Stable CuS Nanosuspension Capped by Bovine Serum Albumin

The biocompatible nanosuspension of CuS nanoparticles (NPs) using bovine serum albumin (BSA) as a capping agent was prepared using a two-stage mechanochemical approach. CuS NPs were firstly synthetized by a high-energy planetary ball milling in 15 min by milling elemental precursors. The stability of nanoparticles in the simulated body fluids was studied, revealing zero copper concentration in the leachates, except simulated lung fluid (SLF, 0.015%) and simulated gastric fluid (SGF, 0.078%). Albumin sorption on CuS NPs was studied in static and dynamic modes showing a higher kinetic rate for the dynamic mode. The equilibrium state of adsorption was reached after 90 min with an adsorption capacity of 86 mg/g compared to the static mode when the capacity 59 mg/g was reached after 2 h. Then, a wet stirred media milling in a solution of BSA was introduced to yield the CuS-BSA nanosuspension, being stable for more than 10 months, as confirmed by photon cross-correlation spectroscopy. The fluorescent properties of the nanosuspension were confirmed by photoluminescence spectroscopy, which also showed that tryptophan present in the BSA could be closer to the binding site of CuS than the tyrosine residue. The biological activity was determined by in vitro tests on selected cancer and non-tumor cell lines. The results have shown that the CuS-BSA nanosuspension inhibits the metabolic activity of the cells as well as decreases their viability upon photothermal ablation.

Imidazole-Based pH-Sensitive Convertible Liposomes for Anticancer Drug Delivery

In efforts to enhance the activity of liposomal drugs against solid tumors, three novel lipids that carry imidazole-based headgroups of incremental basicity were prepared and incorporated into the membrane of PEGylated liposomes containing doxorubicin (DOX) to render pH-sensitive convertible liposomes (ICL). The imidazole lipids were designed to protonate and cluster with negatively charged phosphatidylethanolamine-polyethylene glycol when pH drops from 7.4 to 6.0, thereby triggering ICL in acidic tumor interstitium. Upon the drop of pH, ICL gained more positive surface charges, displayed lipid phase separation in TEM and DSC, and aggregated with cell membrane-mimetic model liposomes. The drop of pH also enhanced DOX release from ICL consisting of one of the imidazole lipids, sn-2-((2,3-dihexadecyloxypropyl)thio)-5-methyl-1H-imidazole. ICL demonstrated superior activities against monolayer cells and several 3D MCS than the analogous PEGylated, pH-insensitive liposomes containing DOX, which serves as a control and clinical benchmark. The presence of cholesterol in ICL enhanced their colloidal stability but diminished their pH-sensitivity. ICL with the most basic imidazole lipid showed the highest activity in monolayer Hela cells; ICL with the imidazole lipid of medium basicity showed the highest anticancer activity in 3D MCS. ICL that balances the needs of tissue penetration, cell-binding, and drug release would yield optimal activity against solid tumors.

Characterizing membrane fouling formation during ultrafiltration of high-salinity organic wastewater

High-salinity organic wastewater usually consists of diverse highly concentrated ions such as Na⁺, Ca²⁺ and Al³⁺ etc., which may significantly influence the fouling propensity when membrane technique is employed for contaminants removal. The current work investigated the effects of high salinity especially high-concentration Na⁺, Ca²⁺ and Al³⁺ on UF fouling characteristics, where 2 M Na⁺ and 0.5-1.0 M Ca²⁺ or Al³⁺ were applied according to the general composition of high-salinity wastewater. The results demonstrated that the presence of high-concentration Na⁺ alone benefited the ultrafiltration of bovine serum albumin (BSA) solution, but posed adverse effects on the ultrafiltration of humic acid (HA) solution. Further addition of Ca²⁺ or Al³⁺ on the basis of Na⁺ was found to aggravate the development of BSA fouling. Such differentiated behaviors were further elucidated by the comprehensive fouling characterizations in terms of foulant properties, specific resistances, filtration modelling and fouling layer observations. Correlation analysis suggested that irreversible fouling had strong relationship with Al³⁺ addition, while reversible fouling seemed to be primarily influenced by foulant size. Meanwhile, membrane rejection in the presence of various salts remarkably decreased, which was negatively correlated with zeta potential. Consequently, this study should shed light on the membrane fouling formation for treating high-salinity organic wastewater using membrane techniques.

Preparation of core–shell nanoparticles via emulsion polymerization induced self-assembly using a maleamic acid-α-methyl styrene copolymer as a macro-initisurf

An amphiphilic maleamic acid-α-methyl styrene copolymer (macro-initisurf) acting as a macroinitiator and emulsifier for the emulsion polymerization induced self-assembly of acrylate monomers to prepare core–shell nanoparticles.

Populus alba L., an Autochthonous Species of Spain: A Source for Cellulose Nanofibers by Chemical Pretreatment

In order to identify new sustainable sources for producing cellulose nanofibers (CNFs), fast-growing poplar (Populus alba L.) wood was evaluated herein. For that purpose, bleached poplar kraft pulp was produced and submitted to TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) mediated oxidation (TEMPO-ox) chemical pretreatment followed by microfluidization. The resulting CNFs were thoroughly characterized, including a rheological study at different pH values. Poplar CNFs showed properties comparable to eucalypt CNFs (reference material for CNFs production), showing high carboxylate content (1048 ± 128 µmol g⁻¹), fibrillation yield (87.3% ± 8.1%), optical transmittance (83% at 700 nm) and thermal stability (up to more than 200 °C). Regarding the rheological study, whereas pH from 4 to 10 did not produce significant changes in rheological behavior, a reduction of pH down to 1 led to an order-of-magnitude increase on the viscoelastic functions. Therefore, poplar CNF shows potential in the pH-sensitive hydrogels application field. Finally, the possible ecotoxicity of poplar CNF was assessed. The decrease in cell viability was very low so that only concentrations causing a 10% cytotoxicity could be calculated for the assay detecting alterations in cell metabolism (10 µg mL⁻¹) and plasma membrane integrity (60 µg mL⁻¹).

Dynamic Constitutional Frameworks as Antibacterial and Antibiofilm Agents

Dynamic constitutional frameworks (DCFs) were synthesized and screened for biofilm inhibition or disruption. They are composed of a trialdehyde core reversibly linked to a diamine PEG connector and to a variety of neutral, anionic, or cationic heads, to generate a library of DCFs to generate multivalent dendritic architectures in the presence of Pseudomonas aeruginosa and Staphylococcus aureus. The best DCFs were always polycationic and the nature of the cationic heads significantly impact the antibiofilm activity. The best antibiofilm activity was observed for DCF3B, displaying a polyethyleneimine head. A simple inactive guanidinium functional head strongly inhibited biofilm growth when assayed as a multivalent DCF3C. Using a more advanced in vitro biofilm model of chronic wound infection, DCF3C was found significantly superior than all other DCFs. These results demonstrate the versatility and effectiveness of DCFs as low cost and efficient systems for antibiofilm disruption.