Low Zeta Potential Research Articles

Novel microemulsions formulated from sodium N-Lauroyl sarcosinate as nanocarrier for encapsulation of α-Tocopherol

Oil-in-water (o/w) microemulsions (MEs) are gaining increasing attention as nanocarriers for the encapsulation and delivery of hydrophobic bioactive molecules which has huge applications in cosmetic, pharmacological, food and beverage industries. However, the major challenge is to formulate these MEs from biodegradable and biocompatible components in low concentration to form stable formulations. In the current work, physiochemical characterization of blank and α-tocopherol loaded o/w MEs formulated using the biodegradable amino-acid based sodium N-lauroyl sarcosinate (SNLS) as surfactant was performed. These MEs were utilized as potential nanocarriers to solubilize and encapsulate an antioxidant α-tocopherol. The utilization of o/w MEs increased the solubility of α-tocopherol from 0.1% in 10% SNLS solution to 0.2% and 0.8% in MEs without and with cosurfactant respectively. The effect of cosurfactant, concentration of Smix (SNLS:butanol = 1:1) and oil was evaluated using conductivity, viscosity studies and encapsulation efficiency to select the optimum composition for encapsulation. The Z-average size of blank MEs without and with cosurfactant was 304 nm and 199 nm respectively with low PDI and negative zeta potential values determine the enhanced stability of these MEs. The HRTEM images revealed the spherical shape of o/w MEs with darker oily core and were utilized to study the effect of cosurfactant and encapsulation of α-tocopherol on the size and morphology of o/w ME droplets. Further, FTIR studies showed the molecular interactions in α-tocopherol and in the optimized ME. In addition to this, the in-vitro antioxidant study of α-tocopherol loaded MEs was determined by the DPPH free radical scavenging activity and the IC50 value was 9 mg/mL for the optimized ME containing 0.5% α-tocopherol. The contact angle studies revealed excellent wetting and spreading ability of MEs on the hydrophobic surface. Thus, SNLS based o/w MEs could be utilized as potential nanocarriers for the encapsulation and delivery of α-tocopherol.

Dynamic light scattering analysis of immune complexes in sera of rheumatoid arthritis patients

The size of circulating immune complexes (CICs) in rheumatoid arthritis (RA) could be an emerging criterion in disease diagnosis. This study analyzed size and electrokinetic potential of CICs from RA patients, healthy young adults, and RA patients age-matched controls aiming to establish their unique CIC features. Pooled CIC of 30 RA patients, 30 young adults, and 30 RA group's age-matched controls (middle-aged and oldеr healthy adults), and in vitro IgG aggregates from pooled sera of 300 healthy volunteers were tested using dynamic light scattering (DLS). Size distribution of CIC in healthy young adults exhibited high polydispersity. RA CIC patients and their age-matched control showed distinctly narrower size distributions compared with young adults. In these groups, particles clustered around two well-defined peaks. Particles of peak 1 were 36.1 ± 6.8 nm in RA age-matched control, and 30.8 ± 4.2 nm in RA patients. Particles of peak 2 of the RA age-matched control's CIC was 251.7 ± 41.2 nm, while RA CIC contained larger particles (359.9 ± 50.5 nm). The lower zeta potential of RA CIC, compared to control, indicated a disease-related decrease in colloidal stability. DLS identified RA-specific, but also age-specific distribution of CIC size and opened possibility of becoming a method for CIC size analysis in IC-mediated diseases.

Low extracellular vesicle concentrations predict survival in patients with heart failure.

Heart disease is of worldwide importance due to high morbidity and mortality. Extracellular vesicle (EV) concentration and size represent novel diagnostic and prognostic biomarkers, e.g. in patients with liver cancer, but data on their prognostic relevance in heart disease are lacking. Here, we investigated the role of EV concentration, size and zeta potential in patients with heart disease. Vesicle size distribution, concentration and zeta potential were measured by nanoparticle tracking analysis (NTA) in 28 intensive care unit (ICU) and 20 standard care (SC) patients and 20 healthy controls. Patients with any disease had a lower zeta potential compared to the healthy controls. Vesicle size (X50) was significantly higher in ICU patients (245 nm) with heart disease as compared to those patients with heart disease receiving standard care (195 nm), or healthy controls (215 nm) (p = 0.001). Notably, EV concentration was lower in ICU patients with heart disease (4.68 × 1010 particles/ml) compared to SC patients with heart disease (7,62 × 1010 particles/ml) and healthy controls (1.50 × 1011 particles/ml) (p = 0.002). Extracellular vesicle concentration is prognostic for overall survival in patients with heart disease. Overall survival is significantly reduced when the vesicle concentration is below 5.55 × 1010 particles/ml. Median overall survival was only 140 days in patients with vesicle concentrations below 5.55 × 1010 particles/ml compared to 211 days in patients with vesicle concentrations above 5.55 × 1010 particles/ml (p = 0.032). Concentration of EVs is a novel prognostic marker in ICU and SC patients with heart disease.

Evaluation of aquaporin based biomimetic forward osmosis membrane in terms of rejection performance for contaminants in greywater and its membrane fouling properties

Forward osmosis (FO) technology is regarded as an alternative to wastewater treatment due to its high permeate flux, excellent solute selectivity and low fouling tendency. In this study, two novel aquaporin based biomimetic membranes (ABMs) were used for comparison in short-term experiments to investigate the impact of membrane surface properties on greywater treatment. The impact of feed solution (FS) temperature on the filtration performance and membrane fouling behavior of ABM was further analyzed in the sequential batch experiments. Results indicated that the membranes with rough surface morphology and low zeta potential (absolute value) facilitated the adsorption of linear alklybezene sulfonates (LAS), thus improving the water flux and the rejection of Ca2+ and Mg2+. The increase in FS temperature enhanced the diffusion of organic matter and the water flux. In addition, sequential batch experiments showed that the membrane fouling layer was mainly in the form of organic and inorganic composite fouling, which was mitigated at FS temperature of 40 °C. Microbial community analysis revealed that the increase in FS temperature affected the diversity of microbial communities. More heterotrophic nitrifying bacteria were enriched in the fouling layer at FS 40 °C than at FS 20 °C. This study provides a novel strategy for employing ABM FO in greywater treatment and reuse.

Chitooligosaccharide-catechin conjugate loaded liposome using different stabilising agents: characteristics, stability, and bioactivities

Aim To determine the optimum condition for preparing chitooligosaccharide-catechin conjugate (COS-CAT) liposomes using different stabilising agents. Methods COS-CAT liposomes (0.1–1%, w/v) were prepared using soy phosphatidylcholine (SPC) (50–200 mM) and glycerol or cholesterol (25–100 mg). Encapsulation efficiency (EE), loading capacity (LC), physicochemical characteristics, FTIR spectra, thermal stability, and structure of COS-CAT liposomes were assessed. Results COS-CAT loaded liposome stabilised by cholesterol (COS-CAT-CHO) showed higher stability as shown by the highest EE (76.81%) and LC (4.57%) and the lowest zeta potential (ZP) (−76.51 mV), polydispersity index (PDI) (0.2674) and releasing efficiency (RE) (53.54%) (p < 0.05). COS-CAT-CHO showed the highest retention and relative remaining bioactivities of COS-CAT under various conditions (p < 0.05). FTIR spectra revealed the interaction between the choline group of SPC and -OH groups of COS-CAT. Phase transition temperature of COS-CAT-CHO was shifted to 184 °C, which was higher than others (p < 0.05). Conclusion SPC and cholesterol-based liposome could be used as a promising vesicle for maintaining bioactivities of COS-CAT.

The effects of Ti and Ta particle surface chemistry on inflammation, osteogenesis and osteoclastogenesis in vitro and in vivo

Tantalum (Ta) and its alloys have attracted extensive attention in orthopedic field, while the underlying mechanism of abrasive debris effects on bone remains unveiled. Therefore, it is essential to explore the effects of Ta wear particle characteristics on macrophage, osteoblast and osteoclast response. In this study, spherical Ti and Ta particles with similar sizes were employed as material models to mimic wear debris. It was found that Ti or Ta particle surfaces were covered by a naturally formed oxide layer, with Ta particle surfaces possessing more hydroxyls and lower zeta potential. The in vitro results showed that Ta particles exhibited much milder modulatory effects on osteoblast, macrophage and osteoclast response than Ti particles. Moreover, the in vivo osteolytic effect of Ta particles was much weaker than that of Ti particles after the injection of these particles into the cranial sites of mice for 2 weeks.

Enhancement of sodium salty taste modulate by protease-hydrolyzed Gum Arabic

Salt reduction strategies in liquid foods remains a significant challenge. The oral perception of Na+ is strongly dependent on its salivary penetration and mucosal adsorption. To understand the mechanism of Na+ saltiness enhancement modulated by polysaccharide, protease hydrolysis (trypsin and acid protease) was used to modify the molecular conformation of Gum Arabic (GA), a highly branched polyanionic polysaccharide. The salivary permeation, mucosal retention in mucin layer, and salty taste of Na+ were investigated. Saltiness-enhanced effect of GA is strongly influenced by its molecular conformation. Compared to native GA, protease-hydrolyzed GA exhibited a higher saltiness-enhanced effect due to more rapid Na+ diffusion in saliva and stronger mucosal retention. Protease-hydrolyzed GA, especially acid protease-hydrolyzed GA (GA-AcPr), exhibited lower zeta potential (from original −22.5 to −27.96) and stronger Na+ loading capacity. The obvious decreases in molecular weight (Mw) and the radius of gyration (Rg) were observed for trypsin-hydrolyzed GA (GA-Trypsin), which may be responsible for the higher Na+ diffusion effect of GA-saliva solution due to decreased molecule twine around each other. GA-AcPr exhibited looser and highly branched conformation, as evidenced by a more pronounced "U-shaped" curve and higher Rg/Rh. Moreover, Quartz crystal microbalance with dissipation (QCM-D) results verified stronger affinity between GA-AcPr and mucin, indicating that the saltiness-enhanced effect of GA-AcPr may be mainly achieved by increasing adhesive retention of Na+. These results would be useful to better understand the structure-function relationship of polysaccharides and the taste perception of Na+.

Formation and Characterization of Self-Assembled Rice Protein Hydrolysate Nanoparticles as Soy Isoflavone Delivery Systems

In this study, soy isoflavones-loaded nanoparticles were prepared using rice proteins (RPs) hydrolyzed by four types of enzyme (alcalase, neutrase, trypsin, and flavorzyme). After optimizing the preparation conditions, the encapsulation efficiency (EE) of the nanoparticles ranged from 61.16% ± 0.92% to 90.65% ± 0.19%. The RPs that were hydrolyzed by flavorzyme with a molecular weight of <5 KDa showed better characters on the formation of nanoparticles, and the formed nanoparticles had the highest EE and loading capacity (9.06%), the smallest particle size (64.77 nm), the lowest polymer dispersity index (0.19), and the lowest zeta potential (-25.64 mV).The results of Fourier transform ion cyclotron resonance, X-ray diffraction, and fluorescence spectroscopy showed that the nanoparticles were successfully encapsulated. The study of interaction showed that the formation of nanoparticles may depend mainly on hydrogen bonds, but other interactions, such as hydrophobic interactions and electrostatic interactions, cannot be ignored. After encapsulation, the pH stability, temperature stability, ionic stability, and oxidation resistance of the nanoparticles were enhanced. Moreover, the in vitro release experiment showed that the encapsulated nanoparticles had a certain protective effect on soybean isoflavones. In summary, rice protein hydrolysates are promising carriers for soybean isoflavones.

Cinacalcet HCl-Loaded PLGA Nanoparticles Using the Porous Carrier

Background: Cinacalcet HCl is a calcimimetic, BCS class IV drug with low oral bioavailability. Polymeric nanoparticles are widely used as biomaterials owing to their biocompatibility, biodegradability, varied structures, low toxicity, and simple and easy formulation process. Objective: The aim of the study was to enhance the oral bioavailability of poorly water-soluble drug, i.e., cinacalcet HCl, by using a suitable particulate nanocarrier system, i.e., polymeric nanoparticles. Methods: Biodegradable Cinacalcet HCl (CH)-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles were prepared by nanoprecipitation method using Poloxamer-188 as a stabilizer. The experimental parameters, like polymer concentration, stabilizer concentration, temperature, and RPM speed, were optimized. An optimized polymeric nanoparticle formulation PNP (F8) was solidified by adsorption on the porous carrier sylysia 350. Results: PNP (F8) exhibited a particle size of 155 nm with low PDI (0.231) and high zeta potential (- 21.3 mV). In vitro diffusion study revealed sustained release of CH for 24 h for both PNP (F8) and solidified PNP (F8). Pharmacokinetics after oral administration of PNP (F8) and solidified PNP (F8) exhibited a 5-fold increase in bioavailability. Thus, both PNP (F8) and solidified PNP (F8) showed significant improvement in oral bioavailability. Conclusion: Adsorption of polymeric nanoparticles onto porous carriers like sylysia 350 can be considered as a promising approach for long-term stability.

Effect of microbial transglutaminase on thermal stability of milk protein

At present, Transglutaminase (abbreviated as TG, EC2.3.2.13) has been used in meat products, dairy products and baked goods in Japan and other countries. The stability of MP (Milk protein) colloid system is very important to the quality of dairy products. The effect of MTG (Microbial TG) on the thermal stability of MP was studied in this experiment. The change of HCT (Heat Coagulation Time) of MP emulsion before and after adding MTG was measured. The results show that the effect of MTG on MP leads to the decrease of its solubility in the region of pH &lt; 4.0 or pH &gt; 7.0, but it increases in the range near the isoelectric point of MP (pH 4.0 ~ 6.0). In the range of acidic pH value with low stability, the high calcium ion activity, low Zeta potential and micelle hydration make the milk have poor thermal stability and will solidify rapidly at 150℃. The hydrophobic interaction between MTG and MP changes the conformation of MP, which leads to the change of thermal stability.

Efficient Removal of Congo Red, Methylene Blue and Pb(II) by Hydrochar–MgAlLDH Nanocomposite: Synthesis, Performance and Mechanism

Organic dyes and heavy metals often coexist in industrial effluents, and their simultaneous removal is a grand challenge. Herein, a hydrochar and MgAl layered double hydroxide (HC-MgAlLDH) nanocomposite was prepared via a facile one-step hydrothermal route, and applied to remove anionic Congo red (CR), cationic Methylene blue (MB) and Pb(II) from aqueous solutions. The nanocomposite was formed by interweaving amorphous HC and crystalline MgAlLDH nanoplates and possessed more functional groups, lower zeta potential and larger specific surface area than uncomposited MgAlLDH. Batch removal experiments showed that the components HC and LDH dominated the CR and MB removals, respectively, whereas Pb(II) removal was conjointly controlled by the two components. The maximum Langmuir removal capacities of the nanocomposite to sole CR, MB, or Pb(II) were 348.78, 256.54 or 33.55 mg/g. In binary and ternary systems, the removal capacities of CR and MB only slightly decreased, while the capacity of Pb(II) increased by 41.13-88.61%. The increase was related to the coordination of Pb(II) with the sulfur-containing groups in dyes and the precipitation of PbSO4. Therefore, the simultaneous removal of CR, MB and Pb(II) was involved in a synergistic effect, including electrostatic adsorption, π-π interaction, coordination and precipitation. The present work shows that the HC-MgAlLDH nanocomposite has great potential for wastewater integrative treatment.

A Comparative Study of Cancer Cells Susceptibility to Silver Nanoparticles Produced by Electron Beam.

Silver nanoparticles (AgNPs) have a wide range of bioactivity, which is highly dependent on particle size, shape, stabilizer, and production method. Here, we present the results of studies of AgNPs cytotoxic properties obtained by irradiation treatment of silver nitrate solution and various stabilizers by accelerating electron beam in a liquid medium. The results of studies of morphological characteristics of silver nanoparticles were obtained by transmission electron microscopy, UV-vis spectroscopy, and dynamic light scattering measurements. MTT test, alamar blue test, flow cytometry, and fluorescence microscopy were used to study the anti-cancer properties. As biological objects for standard tests, adhesive and suspension cell cultures of normal and tumor origin, including prostate cancer, ovarian cancer, breast cancer, colon cancer, neuroblastoma, and leukemia, were studied. The results showed that the silver nanoparticles obtained by irradiation with polyvinylpyrrolidone and collagen hydrolysate are stable in solutions. Samples with different stabilizers were characterized by a wide average size distribution from 2 to 50 nm and low zeta potential from -7.3 to +12.4 mV. All AgNPs formulations showed a dose-dependent cytotoxic effect on tumor cells. It has been established that the particles obtained with the combination of polyvinylpyrrolidone/collagen hydrolysate have a relatively more pronounced cytotoxic effect in comparison to samples stabilized with only collagen or only polyvinylpyrrolidone. The minimum inhibitory concentrations for nanoparticles were less than 1 μg/mL for various types of tumor cells. It was found that neuroblastoma (SH-SY5Y) is the most susceptible, and ovarian cancer (SKOV-3) is the most resistant to the action of silver nanoparticles. The activity of the AgNPs formulation prepared with a mixture of PVP and PH studied in this work was higher that activity of other AgNPs formulations reported in the literature by about 50 times. The results indicate that the AgNPs formulations synthesized with an electron beam and stabilized with polyvinylpyrrolidone and protein hydrolysate deserve deep study for their further use in selective cancer treatment without harming healthy cells in the patient organism.

Mathematical model for numerical simulations of thermal energy of nano-fluid in a complex peristaltic transport within a curved passage:Pharmacological and engineering biomedical application

The proposed scientific model is based on peristaltic movement of nanofluid within a curved channel of an electrically conducting material. To obtain a numerical solution for the electric potential function, the Debye-Hückel and Lubrication theory approximations are used. Stream function, electroosmotic, axial velocity, and curvature are all estimated using low zeta potentials. The behaviour of electroosmotic flow governs two dimensionless parameters: the Debye-Hückel parameter and the Helmholtz-Smoluchowski velocity. It is also investigated how curvature influences blood flow caused by electroosmosis. It was also investigated how the curvature parameter affects the nano-fluid flow induced by electroosmosis. Nano-biofluid evaluation with varied particle shapes such as cylinder, platelet, brick, and blade flowing in complex travelling wave. It can be stated that the velocity component of nanofluid is decreasing due to magnetic force, particle size, and wall compliance. It is also stated that nanoparticles considerably improve the thermal conductivity of the fluid.

Turning Recycled Cardboard Container-Derived Lignin-Containing Cellulose Nanofibrils into a Robust Gas Barrier UV-Shielding Film

Self-standing cellulose nanofibril (CNF) films are regarded as one of the promising alternatives to current petroleum-based packaging materials mostly due to their ability to form dense self-assembled structures exhibiting high gas barrier properties. Nonetheless, one of the major obstacles to the commercialization of these materials in packaging applications is the high cost of raw materials and production energy. In this study, we created self-standing films of lignin-containing cellulose nanofibrils (LCNFs) derived from a recycled old corrugated cardboard (OCC) pulp that costs less than bleached softwood Kraft (BSK) pulp and requires half as much energy for refining to obtain the same quality of material. The low zeta potential (−3.83 mV) of OCC-derived LCNFs (OCC-LCNFs) resulted in aggregation of the fibrils in aqueous suspension, leading to considerable unpredictability in oxygen permeability (OP) values (coefficient of variation 36%). The addition of 3 wt % (based on the dry weight of LCNFs) carboxymethyl cellulose lowered the coefficient of variation to 16% with an average OP of 1478 (cc.μm/m2.atm.day) at 80% relative humidity. Because the OP was higher than that of the CNF film made from BSK-derived CNF (BSK-CNFs), we demonstrated that ionic crosslinking with trivalent aluminum ion or covalent crosslinking with polyamide epichlorohydrin decreased the OP by 30% at 23 °C and 80% relative humidity while also significantly enhancing the tensile strength and modulus. In addition, the presence of lignin in OCC resulted in a relatively lower water vapor permeability value in OCC-LCNF films compared to BSK-CNF films. Moreover, OCC-LCNF films showed complete UV-shielding (200–400 nm) property. Overall, this work provides a new opportunity to exploit a recycled and inexpensive source of CNFs to produce robust gas barrier materials for packaging applications.

Study on the synchronous removal mechanisms of typical refractory hydrophilic and hydrophobic organics in the biochemical effluent of coal gasification by semicoke-PSAFS

To study the synchronous removal mechanisms of hydrophilic organics 2,4-di-tert-butylphenol and 2-palmitoyl-rac-glycerol and the hydrophobic organics n-octadecane and 2-stearoyl-rac-glycerol coexisting in the biochemical effluent of coal gasification processes treated by a semicoke-polysilicate aluminum ferric sulfate (PSAFS) process, the fitting results of the D-R adsorption isotherm model show that the maximum equilibrium adsorption qe for hydrophobic organics was 3.2–7.8 times that of hydrophilic organics. Based on the contrast with 8 kJ/mol of the average adsorption free energy, physical adsorption occurred in the hydrophobic organics, and chemical adsorption occurred in the hydrophilic organics. Adsorption kinetics analysis showed that the adsorption rates of three typical organics except for 2-palmitoyl-rac-glycerol increased by more than 40.0% in semicoke-PSAFS compared with the semicoke adsorption. To analyze the adsorption driving forces, a linear solvation energy relationship (LSER) model was selected and showed that the hydrogen-bond acid effect contributed by PSAFS had the largest regression coefficients among the five adsorption forces. The typical hydrophilic organics had lower zeta potentials than hydrophobic organics, which suggests that hydrophilic organics that were easily ionized at neutral pH were electrostatically neutralized with the Fe and Al cations in PSAFS. The floc in hydrophilic organic solutions had larger D50 and Df than those in hydrophobic organic solutions, which indicates that the hydrophilic organics had polar functional groups that combined with the silicon, iron and aluminum polymers in PSAFS through a hydrogen-bonded acid effect to form larger and denser floc structures. Hydrophobic organics were adsorbed in the pores of semicoke; then, in combination with semicoke, they were captured by the iron and aluminum polymers in PSAFS.

Multiscale Wettability Characterization of Anhydrite-Rich Carbonate Rocks: Insights into Zeta Potential, Flotation, and Contact Angle Measurements

Summary Anhydrite (CaSO4) is a chemically reactive rock/mineral found predominantly as a constituent of carbonates. The main constituents of anhydrite are calcium and sulfate ions. The presence of anhydrite, its distribution, and the associated anhydrite-fluid interactions are important to precisely evaluate the effectiveness of oil recovery techniques. While anhydrite dissolution is the key interaction mechanism in anhydrite-rich rocks, its presence may also lead to complex rock wetting behavior. The underpinning logic is that pure anhydrite is strongly water-wet, while pure calcite and dolomite are somewhat intermediate to weakly oil-wet, thus the question remains unclear as to what the wettability would be of anhydrite and calcite, and anhydrite and dolomite combinations. Moreover, because anhydrite is negatively charged while dolomite and calcite in formation water (FW) are positively charged, depending on the mixture composition, pH, and brine type, it is not clear what the charge would be of a combination of anhydrite-calcite or anhydrite-dolomite, and, consequently, what the wetting behavior of calcite and dolomite would be due to anhydrite presence. Therefore, this research explores the effect of anhydrite mineral on carbonate wetting characteristics. The effect of mineralogical heterogeneity, specifically the presence of anhydrite minerals in calcite and dolomite wettability, is investigated across a range of scales. The results show that anhydrite dissolution occurs in deionized (DI) water, seawater (SW), and FW as evident from the general increase in sulfate ions concentration with increased anhydrite content in the anhydrite-carbonate system. We also found that zeta potential demonstrates an unstable colloidal system, which is indicated by near-zero and low zeta potential values (less than ±10) of the anhydrite-carbonate-brine systems. It also shows a nonmonotonic wetting behavior with brine salinity and pH variations. Accordingly, the zeta potential is not a general and valid candidate to justify the wettability behavior of heterogeneous carbonates. However, based on flotation and contact angle techniques of wettability estimation, anhydrite presence has the tendency to alter the wetting state of anhydrite-carbonate-brine-oil systems to more water-wet. Thus, findings from this research will provide answers to the question of how the mineralogy affects the wetting characteristics of carbonates. What will be the changes in carbonate wetting behavior with mineralogical heterogeneity? Specifically, what would be the wettability of calcite-anhydrite and dolomite-anhydrite combinations? This research therefore provides a systematic investigation of rock/fluid interactions and their implications on wettability and ultimate recovery of oil at different range scales. The findings from this study will significantly enhance our knowledge of fluid-rock interactions, in particular, anhydrite-rich carbonate wetting behavior, thereby reducing the uncertainties associated with laboratory-scale predictions and oil recovery planning.

Transport of a reactive solute in electroosmotic pulsatile flow of non-Newtonian fluid through a circular conduit

• Unsteady nature of dispersion of a solute in electro - hydrodynamic pulsatile flow of Carreau fluid in a uniform channel filled is studied. • The new observation is that the convection coefficient and dispersion coefficient (dispersion of a solute) is enhanced due to increase in the Debye–Hückel parameter. • Dispersion process of a solute is remarkably improved by an increment in the pulsatile Reynolds number ( α ) and unsteady part pressure gradient ( A ) . • It is, for the first time, revealed that solute dispersion in Carreau fluid flow is maximum for the case of diabetic diseased blood and minimum in the anemic disorder case. The present mathematical model discusses the solute dispersion mechanism in a circular conduit by considering pulsatile flow of Carreau fluid. The axial solute distribution process in a circular tube has been analyzed using the generalized dispersion technique and finite Hankel transforms. The momentum equations and constitutive equation to describe the rheology of Carreau fluid are solved by perturbation method with suitable boundary condition and obtained fluid velocity profile. The coefficients of solute dispersal and convection of the concentration profile have been analytically obtained with the help of the assumptions of low zeta potential and a low Reynolds number. The effects of the Debye–Hückel parameter, Weissenberg number, Pulsatile Reynolds number, chemical reaction parameter, and time-dependent pressure gradient on the dispersion environment have been premeditated. The development in fluid velocity and solute concentration profiles are studied realistically for accurate ranges of the distinct physical parameters. The most important outcome of the present investigation is an increment in the Debye–Hückel parameter enhancing the dispersion mechanism in the circular tube. Furthermore, this study highlights the clinical aspect of the electrohydrodynamic solute dispersion's nature in normal as well as disease-affected blood. The present study might contribute to the design and fabrication of surgical tools and development of laboratory equipment in the fields of medical and bioengineering. Furthermore, the results obtained could play a key role in understanding the transportation of nutrients and dispersion process of drugs in the blood circulation.

Aqueous Dispersions of Polypropylene: Toward Reference Materials for Characterizing Nanoplastics.

Microplastics and nanoplastics pollute the natural environment all over the world, but the full extent of the hazards posed by this waste is unclear. While research on microplastics is well advanced, little work has been done on nanoplastics. This discrepancy is mainly due to the lacking ability to detect nanoplastics in biologically and environmentally relevant matrices. Nanoplastics reference materials can help the development of suitable methods for identifying and quantifying nanoplastics in nature. The aim is to synthesize nanoplastics made from one of the most commonly used plastics, namely polypropylene. An easy way to produce long-term stable aqueous dispersions of polypropylene nanoparticles (nano polypropylene) is reported. The nanoplastic particles, prepared by mechanical breakdown, show a mean hydrodynamic diameter of Dh = 180.5 ± 5.8 nm and a polydispersity index of PDI = 0.084 ± 0.02. No surfactant is needed to obtain dispersion which is stable for more than 6 months. The colloidal stability of the surfactant-free nano polypropylene dispersions is explained by their low zeta potential of ζ = -43 ± 2mV.

Novel approaches to the formation of coatings based on gold nanoparticles and albumin for chiral separation in capillary electrophoresis

Combination of properties of gold nanoparticles and bovine serum albumin is promising for the formation of chiral stationary phases enabling high enantioselectivity due to developed surface of coatings and increased chiral selector concentration on the capillary walls. In this work we proposed and compared two approaches to the formation of physically adsorbed multilayer coatings based on citrate-stabilized gold nanoparticles (cGNP) and bovine serum albumin (BSA) for the chiral separation in capillary electrophoresis. In the first approach pre-synthesized cGNP modified with BSA were immobilized on the capillary coated by poly(diallyldimethylammonium chloride) (PDADMAC). PDADMAC polymer was used as a binding layer promoting sorption of the nanoparticles on the capillary surface. It was shown that cGNP-BSA was poorly adsorbed on the capillary surface due to low zeta potential and could not be used for the formation of dense coatings. The second approach included sequential layer-by-layer deposition of PDAMAC and cGNP, resulting in the formation of a dense layer of nanoparticles. The main stage included in-capillary functionalization of cGNP with BSA. Scanning electron microscopy confirmed that the layer-by-layer deposition of modifiers ensured the formation of dense layer of nanoparticles on the capillary surface. The coating was stable in the entire range of pH studied (2–10). The application of such coating allowed reduction of BSA concentration (to 5 μM) in the background electrolyte required for the tryptophan enantiomers separation. It confirms the prospectiveness of combining nanoparticles and chiral selectors for the increase of specific surface area of the capillary inner walls.

Effect of nixtamalization on gluten-free whole corn, dough viscoelasticity, and the bread-making quality of leavened corn bread

Recently, the increment in grain costs and the demand for gluten-free bread has made corn attractive for the production of leavened bread. The nixtamalization process enhances bread functionality. The objective of this study is to determine the effect of traditional nixtamalization, using Ca(OH)2, and ecological nixtamalization, using Ca salts (CaCl2, ashes, tequesquite), on corn-structured, gluten-free bread's loaf volume and quality.To our knowledge, gluten-free corn bread formation was achieved for the first time using nixtamalization. Whole corn dough with CaCl2 showed the best rheological performance. Loaf volume increased with nixtamalization in all cases compared with the non-nixtamalized control. Lower zeta potential (ζ) values, a pH of 6.04 in the dough with CaCl2 and a basic pH of 7.20 in the dough with Ca(OH)2, significantly increased α-helix and antiparallel β-sheet (1685 cm−1) bands and enhanced molecular aggregation. Loaf volume also increased compared with the doughs of the control and quasi-neutral pH treatments. The nixtamalized reduced corn confirmed typical zein bands. Whole corn bread with tequesquite showed a high overall sensory score with potential commercial applications.