•Interactions of polyphenols with yeast protein extract, mannoproteins and β-glucans.•Binding experiments, titration calorimetry and dynamic light scattering studies were done.•Higher interactions ...for yeast protein extract than mannoproteins.•No interaction leading to the formation of aggregates with β-glucan.•Strong impact of the polyphenol structures and protein content on the interactions.
At present, there is a great interest in enology for yeast derived products to replace aging on lees in winemaking or as an alternative for wine fining. These are yeast protein extracts (YPE), cell walls and mannoproteins. Our aim was to further understand the mechanisms that drive interactions between these components and red wine polyphenols. To this end, interactions between grape skin tannins or wine polyphenols or tannins and a YPE, a mannoprotein fraction and a β-glucan were monitored by binding experiments, ITC and DLS. Depending on the tannin structure, a different affinity between the polyphenols and the YPE was observed, as well as differences in the stability of the aggregates. This was attributed to the mean degree of polymerization of tannins in the polyphenol fractions and to chemical changes that occur during winemaking. Much lower affinities were found between polyphenols and polysaccharides, with different behaviors between mannoproteins and β-glucans.
The inherent thermodynamic instability of liposomes during production and storage has limited their widespread applications. Therefore, a novel structure of food-grade nanoliposomes stabilized by a ...3D organogel network within the bilayer shell was developed through the extrusion process and successfully applied to encapsulate vitamin D3. A huge flocculation and a significant reduction of zeta potential (−17 mV) were observed in control nanoliposomes (without the organogel shell) after 2 months of storage at 4 °C, while the sample with a gelled bilayer showed excellent stability with a particle diameter of 105 nm and a high negative zeta potential (−63.4 mV), even after 3 months. The development of spherical vesicles was confirmed by TEM. Interestingly, the gelled bilayer shell led to improved stability against osmotically active divalent salt ions. Electron paramagnetic resonance confirmed the higher rigidity of the shell bilayer upon gelation. The novel liposome offered a dramatic increase in encapsulation efficiency and loading of vitamin D3 compared to those of control.
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•Effect of bile salts on T1304 micelles was checked using various scattering and spectroscopical techniques.•Solubilization of anticancer drug Quercetin was checked using HPLC.•The ...presence of bile salts induces micellar breakdown resulting in smaller micelles.•In the presence of bile salts, solubilizing environment become less favourable for the solubilization of the drug.
Here we report, the interaction of a star block copolymer T1304 and biologically important additive, bile salts (BS) in aqueous condition. Bile salts used for the system are sodium cholate (NaC), sodium taurocholate (NaTC) and sodium deoxycholate (NaDC). Mixed micelles of T1304-BS have been assessed by employing cloud point (CP), scattering dynamic light scattering (DLS), small-angle neutron scattering (SANS) and spectral techniques UV–visible, 1H NMR, and fluorescence spectroscopy. As the system is comprising of two important bio amphiphiles, so the solubilization of drug Quercetin (QCT) in this mixed micellar environment is also studied to give it a broader spectrum. An increased trend in CP along with a decrease of micellar size is observed with the addition of BSs. With increasing concentration of bile salts, the mixed micellar aggregates are becoming surfactant rich and maximum replacement of T1304 molecule is done by NaDC due to its lower CMC and more hydrophobicity.
Cholesterol-rich nanoemulsion (LDE) can carry chemotherapeutic agents in the circulation and can concentrate those agents in the neoplastic and inflammatory tissues. This method improves the ...biodistribution of the drug and reduces toxicity. However, the structural stability of LDE particles, without or with associated drugs, has not been extensively investigated. The aim of the present study is to investigate the structural stability of LDE and LDE associated to paclitaxel, etoposide or methotrexate in aqueous solution over time by small-angle X-ray scattering (SAXS and Ultra SAXS) and dynamic light scattering (DLS). The results show that LDE and LDE associated with those chemotherapeutic agents had reproducible and stable particle diameter, physical structure, and aggregation behavior over 3-month observation period. As estimated from both DLS and Ultra-SAXS methods, performed at pre-established intervals, the average particle diameter of LDE alone was approx. 32 nm, of LDE-paclitaxel was 31 nm, of LDE-methotrexate was 35 nm and of LDE-etoposide was 36 nm. Ultra-SAXS analysis showed that LDE nanoparticles were quasi-spherical, and SAXS showed that drug molecules inside the particles showed a layered-like organization. Formulations of LDE with associated PTX, ETO or MTX were successfully tested in animal experiments and in patients with cancer or with cardiovascular disease, showing markedly low toxicity, good tolerability and possible superior pharmacological action. Our results may be useful for ensuing clinical trials of this novel Nanomedicine tool, by strengthening the knowledge of the structural aspects of those LDE formulations.
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•We investigate the structural stability of cholesterol-rich nanoemulsion (LDE) and LDE associated to paclitaxel, etoposide or methotrexate in aqueous solution over time by small-angle X-ray scattering (SAXS and Ultra SAXS) and dynamic light scattering (DLS). LDE carry chemotherapeutic agents in the circulation and can concentrate those agents in the neoplastic and inflammatory tissues.•The results show that LDE and LDE associated agents had reproducible and stable particle diameter, physical structure, and aggregation behavior over 3-month observation period.•Ultra-SAXS experiments showed that the average particle diameter of LDE alone was approx. 32 nm, of LDE-paclitaxel was 31 nm, of LDE-methotrexate was 35 nm and of LDE-etoposide was 36 nm.•SAXS experiments showed, in some preparations, that drug molecules inside the particles showed a layered-like organization.
Nanoscale gas bubbles are paid more and more attention due to their significant applications in different fields including the environmental remediation, plant and animal growth as well as medical ...diagnosis, etc. As reported, the local gas saturation plays an important role for the formation of surface nanobubbles (NBs) but is less importance for their stability. As for bulk NBs, few researches focused on the influence of dissolved gas on their generation and stability because it is thought generally that a limited amount of gas could dissolve into water. Herein, we reported for the first time the relationship of dissolved gases (Kr, O2 and N2) and the formation and stability of bulk NBs. Firstly, we developed a compression-decompression method to produce the water with super-high concentration of dissolved gas. About 60 mg/L oxygen dissolved gas was created to promote the formation of bulk NBs. It was showed that high bulk NB concentrations were produced using the compression-decompression method by controlling the loading pressure and time at the same time. The evolution process showed that the concentration of dissolved gas would decrease quickly with the deposited time. However, the concentration of formed bulk NBs did not follow the same way as dissolved gas concentration. It exhibited a complicated change over the time. Typically, first sharp increase to one order higher concentration than at the beginning and then decreased with a fluctuation within 72 h. More interestingly, the time of this sharp increase in nanobubble concentration depended on the type of gas, the krypton (Kr) gas system took longer time to reach the highest concentration and the oxygen (O2) as well as nitrogen (N2) gas system reached the highest concentration at about 4 h generally. The change of zeta potential of those NBs followed the same fluctuation as their concentration. Finally, we presumed a theoretical model to explain the evolution mechanism of bulk NBs. It indicated that there is a competition of different bubble behaviors (nucleation, clustering and coalescence) in different time periods. This study provides a new technique to produce high concentration of bulk NBs and dissolved gas in solution. Those results are very significance for further understanding the mechanism of formation and stability of bulk NBs under a super-high concentration of dissolved gas and may be used in some chemical reactions related with gas to promote the reaction efficiency.
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Cosmetics are part of the daily life of most of the people. Thus, a complete characterization of the products we applied in our skin is necessary. In this work, an analytical investigation of a wide ...variety of cosmetics from the point of view of total element content and metallic nanoparticles (NPs) has been performed. Firstly, we analyzed the total element content by ICP-MS and ICP-OES after acid digestion as an assessment of the presence of metal impurities. Prohibited elements in cosmetics, according to the European Commission regulation No 1223/2009, were not detected, and only elements mentioned in the label were found (e.g. Al, Fe, Ti and Si). Secondly, a screening of the presence of NPs has been performed by Dynamic Light Scattering (DLS) and Single Particle Inductively-Coupled Plasma Mass Spectrometry (SP-ICP-MS). Two sample preparation procedures were applied. The first protocol consisted in the preparation of suspensions in 0.1% w/v SDS and the second based on defatting with hexane followed by resuspension in water. DLS was employed as a routine method for a fast analysis of NPs, but this technique showed limitations due to the lack of specificity. SP-ICP-MS analyses were then performed, first as a screening technique to evaluate the presence of TiO2 and Au NPs in cosmetics suspensions prepared in SDS; and second, when a positive answer was obtained about the presence of NPs from the screening, SP-ICP-MS was used for particle size determination. Results showed that only TiO2 NPs were present in two sunscreens, one anti-wrinkle day cream, one lip balm protector labeled as ‘nano’ and in one brand of toothpaste not labeled as ‘nano’. Sizes obtained for both sample preparations were compared and ranged from 30 to 120nm in most of the samples.
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•Sunscreens, toothpastes, shampoos, face creams and lip balm have been analyzed.•Screening of TiO2 nanoparticles has been performed in cosmetics.•DLS and SP-ICP-MS techniques have been applied and compared.•Elemental impurities were determined by ICP-OES and ICP-MS after sample digestion.•TiO2 nanoparticles were found in ‘nano’- labeled products and in one non-labeled.
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Nanoparticle Tracking Analysis (NTA) is an emerging technique for detecting simultaneously sub-micron particle size distributions and particle concentrations of a sample. This study ...deals with the performance evaluation for the detection and characterisation of various particles by NTA. Our investigation focusses on the NTA measurement parameter set-ups, as will be shown in this study, are very crucial parameters to correctly analyse and interpret the data. In order to achieve this, we used (i) polystyrene standard particles as well as (ii) protein particles.
We show the highly precise and reproducible detection of particle size and concentration in monodisperse polystyrene particle systems, under specified and constant parameter settings. On the other hand, our results exemplify potential risks and errors while setting inadequate parameters with regards to the results and thus interpretation thereof. In particular changes of the parameters, camera level (CL) and detection threshold (DT), led to significant changes in the determined particle concentration. We propose defined and specified “optimal” camera levels for monodisperse particle suspension characterisations in the size range of 20–1000nm. We illustrate that the results of polydisperse polystyrene standard particle solution measurements, highly depend on the used parameter settings, which are rarely published with the data. Changes in these settings led to the “appearance” or “disappearance” of particle populations (”peaks”) for polydisperse systems. Thus, a correct evaluation of the particle size populations in the sample becomes very challenging.
For the use of NTA in biopharmaceutical analysis, proteinaceous samples were investigated. We analysed protein particle suspensions and compared unstressed and stressed (formation of aggregates) protein samples similar to polystyrene particle analysis. We also studied these samples in two different measuring modes (general capture mode and live monitoring mode) that the commercially available analysis software is offering. Our results stated the live monitoring mode as more suitable for protein samples, as the results were more reproducible and less operator-depending.
In conclusion, NTA is a potential technique and unique in quantitative evaluation of particle suspensions in the subvisible size range, especially for monodisperse suspensions. We strongly urge on not underestimating the influence of the measuring parameters on the obtained results, which should be presented with the data in order to better judge and interpret the NTA results.
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The performance of bicontinuous microemulsions is usually assessed on the characteristics of the middle phase at equilibrium. However, applied to Enhanced Oil Recovery, such an ...evaluation would not be representative of the structure and composition of fluids in reservoir rocks. Studies on the properties of non-equilibrated microemulsions are still needed to better understand the formation of such complex systems, in particular to optimize input parameters of process simulation tools.
For this purpose, we monitored the formation of a microemulsion from contact with the oil to equilibrium when no mixing or convection is provided. Non-destructive methods such as Nuclear Magnetic Resonance, Micro-Computed Tomography, Dynamic Light Scattering and Small Angle X-ray scattering were used to extract the compositions, phase thicknesses, dynamics and structures of the system over time.
We found that the system gets structured into several layers over time that include the transient presence of an oriented semi-crystalline phase. The growth of the bicontinuous middle phase results from a progressive reorganization of the liquid crystal. The compositional and structural gradients, observed along the sample height, are correlated and linked to the corresponding structures of the phase diagram of the quaternary system. Equilibrium is reached after the total transfer of the liquid crystal into the bicontinuous phase.
The green synthesis of metallic nanoparticles has paved the way for improving and protecting the environment by decreasing the use of toxic chemicals and eliminating biological risks in biomedical ...applications. Biological synthesis of metal nanoparticles is gaining more importance due to simplicity, rapid rate of synthesis and eco-friendliness. In the present investigation cyanobacterial (Microchaete NCCU-342) cell free aqueous extract has been used for optimizing biosynthesis of silver nanoparticles (AgNP). The optimized reaction parameters for efficient synthesis of AgNP were: biomass quantity of 80 μg/ml, pH 5.5, 60 °C temperature, duration of 60 min UV light exposure and 1 mM AgNO3 concentration. AgNP was characterized by UV–Visible Spectrophotometery, Transmission Electron Microscopy and Dynamic light scattering. The smallest nanoparticles (obtained from biomass parameter were spherical, polydisperessed and in the range of 60-80 nm) were characterized further in a degradation study of azo dye methyl red. Degradation of methyl red within 2 h was more with AgNP (84.60%) as compared to cyanobacterial extract (49.80%).
•Microchaete NCCU-342 aqueous extract has been used for optimizing silver nanoparticles synthesis.•Best optimized conditions were: biomass quantity 80 μg/ml, pH 5.5, 60 °C temperature, duration 60 min UV light exposure and 1 mM AgNO3 concentration.•AgNP were characterized by UV–Visible Spectrophotometery, Transmission Electron Microscopy and Dynamic light scattering.•Spherical, polydispersed and smallest nanoparticles (60-80 nm) were obtained •Synthesized AgNP were further used in degradation study of azo dye methyl red. AgNP were more efficient than cyanobacterial extract.
The present study reports a comparison on aggregation behaviour of PEO-PPO star block copolymers Tetronics® 1304 and 1307 in the presence of toluene, phenol and methyl phenols viz. o-cresol, ...m-cresol, p-cresol. These organic compounds are frequently used in plastics, dyes, pesticides and pharmaceutical industries. Star block copolymers, Tetronics®, are used to solubilise different poorly aqueous soluble substances for a long time in different industrial applications. So, to understand the influence of these solvents on the micellar dimensions of star block copolymers T1304 and T1307 with varied hydrophobicity, dynamic light scattering (DLS) and small angle neutron scattering (SANS) techniques are used. The result reveals the presence of spherical micelles for both the copolymers. However, a significant growth in micellar size is observed with continuous addition of these organic solvents as additives. Maximum micellar growth is observed in the presence of o-cresol and minimum in the presence of toluene.
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