scholarly journals Structural Changes of the Lipid Model Systems in the Presence of Enzymes or Silver Nanoparticles

2021 ◽  
Vol 11 (6) ◽  
pp. 15068-15074
Keyword(s):  
Surface Tension ◽  
Silver Nanoparticles ◽  
Structural Changes ◽  
Particle Diameter ◽  
Biological Membranes ◽  
Egg Yolk ◽  
Model Systems ◽  
Scattering Method ◽  
Dynamic Light Scattering Method ◽  
Equilibrium Surface Tension

This work aimed to study the interaction of silver nanoparticles (AgNP) and lipases with models of biological membranes based on natural phospholipid and cholesterol. The crude phosphatidylcholine from egg yolk (PCe1) and synthetic cholesterol (Chol) were obtained from Sigma-Aldrich. Porcine pancreatic lipase (PPL) was obtained by purification from the hog pancreas. AgNP dispersion was prepared by the well-known citrate method. Measurement of surface tension (ST) was carried out using a BPA-1P device. The equilibrium surface tension (eST) was obtained by calculating the ST-time isotherms using the ADSA program. The particle sizes were determined by the dynamic light scattering method. An addition of AgNPs led to a pronounced decrease in both ST and eST (whereas almost no changes occurred by lipase addition), and AgNPs destructed the large lipid particles. The average lipid particle diameter values changed drastically, whereas the effective particle diameter values were almost the same by lipase addition. Thus, the interactions of AgNPs or lipase with the mixture of natural phospholipid and cholesterol have had entirely different features. These effects are interesting for modeling the interactions of inorganic and organic compounds with biological membranes.

scholarly journals PECULARITIES OF MICELLE FORMATION OF PENTACYCLIC GLYCOSIDES IN AQUEOUS SOLUTIONS

2021 ◽  
Vol 64 (4) ◽  
pp. 26-33
Author(s):  
Natalia V. Mironenko ◽  
Irina V. Shkutina ◽  
Vladimir F. Selemenev
Keyword(s):  
Surface Tension ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Aqueous Solutions ◽  
Hydrodynamic Radius ◽  
Critical Concentration ◽  
Micelle Formation ◽  
Cylindrical Shape ◽  
Scattering Method ◽  
Dynamic Light Scattering Method

The regularities of changes in structural characteristics during the formation of associates in micellar aqueous solutions of triterpene saponins Quillaja Saponin and Sapindus Mukorossi are considered. The dependence of surface tension and adsorption on the concentration of an aqueous saponin solution is analyzed, and the values of surface activity and parameters of the adsorption layer are calculated. The average values of diffusion coefficients for spherical and cylindrical micelles are determined based on the measurement of the solution viscosity. The effect of the electrolyte solution on the surface tension and viscosity of glycoside solutions is studied: when the electrolyte is introduced into the saponin solution, the surface tension decreases, which leads to a shift in the critical concentration of micelle formation towards lower concentrations. The introduction of potassium chloride electrolyte reduces the degree of ionization and, as a result of suppressing the electroviscosity effect, leads to a decrease in the viscosity of the solution. The dynamic light scattering method is used to determine the size of glycoside aggregates. It is established that there are aggregates of several sizes in an aqueous solution of saponin. The size and shape of aggregates were calculated using the concepts of micelle packing parameters. In the region of very low concentrations of glycoside solutions, when approaching the critical concentration of micelle formation in the solution, there are spherical micelles. A further increase in the saponin concentration in the solution leads to a decrease in the content of structures with a hydrodynamic radius of 50-80 nm and the appearance of larger agglomerates with sizes greater than 100 nm. It was found that micelles acquire a less hydrated and more densely packed cylindrical shape in the concentration range of 1.7-2.6 mmol/dm3. Compaction of associates leads to an increase in the content of particles with a hydrodynamic radius of 150-250 nm and larger ones, and their presence predicts the appearance of larger agglomerates. Analyzing the data obtained using the dynamic light scattering method, it can be concluded that aggregates of several sizes co-exist in the volume of aqueous saponin solutions at certain concentrations.

Effects of UV Radiation and pH of Tannic Acid Solution in the Synthesis of Silver Nanoparticles

2014 ◽  
Vol 911 ◽  
pp. 110-114
Author(s):  
Kanitta Watcharaporn ◽  
Mantana Opaprakasit ◽  
Vimolvan Pimpan
Keyword(s):  
Silver Nanoparticles ◽  
Acid Solution ◽  
Uv Radiation ◽  
Tannic Acid ◽  
Suitable Condition ◽  
Scattering Method ◽  
Dynamic Light Scattering Method ◽  
Transmission Electron ◽  
Uv Visible ◽  
Tannic Acid Solution

The reductions of silver nitrate by tannic acid at various pH with and without UV radiation at room temperature were done in order to study the effects of UV radiation and pH of tannic acid solution in the synthesis of silver nanoparticles. The results from UV-Visible spectroscopy, dynamic light scattering method and transmission electron microscopy indicated that using UV radiation resulted in silver nanoparticles with smaller particles and narrower size distribution at every pH. The results also revealed that smallest particles without agglomeration were obtained when alkali condition was applied. Therefore, the suitable condition for synthesizing silver nanoparticles in this research was to use UV radiation and tannic acid solution having pH of 8.0.

scholarly journals Acute and Sub-acute Toxicity of Ganoderma applanatum (Pres.) Pat. Extract Mediated Silver Nanoparticles on Rat

2019 ◽  
Vol 11 (3) ◽  
pp. 351-363 ◽  
Author(s):  
Sukumar DANDAPAT ◽  
Manoj KUMAR ◽  
Rakesh RANJAN ◽  
Manoranjan P. SINHA
Keyword(s):  
Silver Nanoparticles ◽  
Body Weight ◽  
Secondary Amines ◽  
Scattering Method ◽  
Spectroscopy Analysis ◽  
Medicinal Uses ◽  
Dynamic Light Scattering Method ◽  
Primary And Secondary Amines ◽  
Rbc Indices ◽  
Wbc Count

Ganoderm applanatum is a polypore macrofungi and traditionally used as medicine rather than fodder. Silver nanoparticles mediated by G. applanatum extract were synthesized, characterized and toxicity impacts were investigated for their pharmacological and medicinal uses. The synthesized silver nanoparticles were of average 58.78 nm in diameter with -13.8 mV zetpotential, analysed by dynamic light scattering method. Fourier transform infrared spectroscopy analysis of synthesized nanoparticles confirmed the capping and stabilizing with mycochemicals, that showed transmittance at   3606 cm-1 corresponds to O-H stretch for phenol, 2430 cm-1 corresponds to N-H stretch for primary and secondary amines. 2000 mg kg-1, 200 mg kg-1 and 400 mg kg-1 doses of silver nanoparticles showed non-significant (p<0.05) increase in body weight and organ weight. Non-significant increase in RBC indices were observed and significant (p<0.05) increase in WBC count (7.28±0.41 × 103 µL-1 and 8.41±0.35 × 103 µL-1) at 200 mg kg-1 and 400 mg kg-1 doses of silver nanoparticles  were observed. Thus, G. applanatum extract mediated silver nanoparticles can be used pharmacologically and medicinally due to their nontoxic effect.

Surface tension and size effects in multicomponent systems based on lipids and lipase with the introduction of silver nanoparticles

2021 ◽  
Vol 1 (8) ◽  
pp. 90-94
Author(s):  
S. Yu. Zaytsev ◽  
◽  
I. V. Milaeva ◽  
Keyword(s):  
Surface Tension ◽  
Silver Nanoparticles ◽  
Cell Membranes ◽  
Particle Diameter ◽  
Small Diameter ◽  
Sharp Decrease ◽  
Average Diameter ◽  
Biological Action ◽  
Average Particle ◽  
Multicomponent Systems

In recent years, the study of the biological action of silver nanoparticles, especially their interaction with cell membranes, has been of particular interest. The study of complex systems that simulate cell membranes, the nature of their interaction with silver nanoparticles in different concentrations, as well as the effect of lipolytic enzymes on the resulting complexes is of fundamental and applied importance. We investigated multicomponent systems based on egg phosphatidylcholine and cholesterol in a ratio of 14:1 in the presence of lipase (at a concentration of 1,0 rel.u.) after adding silver nanoparticles (AgNPs) at concentrations from 0,01 to 1,0 rel.u. The appearance in the mixture of a large number of small-diameter AgNPs leads to a sharp decrease in the average particle diameter and a slight decrease in the surface tension (ST) of the system. In our opinion, the decisive importance for reducing the ST is not so much the presence of small particles as their number, which is reflected in the ratio of the values of the average and effective diameters. The most pronounced decrease in the average diameter and an increase in the values of this ratio begin due to the AgNPs addition at a concentration of 0.1 rel.u. A decrease in ST by 0,5 mN/m occurs in the system due to the AgNPs addition at a concentration of 1,0 rel.u.

scholarly journals A pH-Responsive Foam Formulated with PAA/Gemini 12-2-12 Complexes

2021 ◽  
Vol 5 (3) ◽  
pp. 37
Author(s):  
Hernán Martinelli ◽  
Claudia Domínguez ◽  
Marcos Fernández Leyes ◽  
Sergio Moya ◽  
Hernán Ritacco
Keyword(s):  
Surface Tension ◽  
Dynamic Surface Tension ◽  
Foam Formation ◽  
Ph Responsive ◽  
Dynamic Surface ◽  
X Ray ◽  
Equilibrium Surface Tension ◽  
Potential Applications ◽  
The Stability ◽  
Air Interfaces

In the search for responsive complexes with potential applications in the formulation of smart dispersed systems such as foams, we hypothesized that a pH-responsive system could be formulated with polyacrylic acid (PAA) mixed with a cationic surfactant, Gemini 12-2-12 (G12). We studied PAA-G12 complexes at liquid–air interfaces by equilibrium and dynamic surface tension, surface rheology, and X-ray reflectometry (XRR). We found that complexes adsorb at the interfaces synergistically, lowering the equilibrium surface tension at surfactant concentrations well below the critical micelle concentration (cmc) of the surfactant. We studied the stability of foams formulated with the complexes as a function of pH. The foams respond reversibly to pH changes: at pH 3.5, they are very stable; at pH > 6, the complexes do not form foams at all. The data presented here demonstrate that foam formation and its pH responsiveness are due to interfacial dynamics.

scholarly journals Nanoemulsion Gel Formulation Optimization for Burn Wounds: Analysis of Rheological and Sensory Properties

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1416
Author(s):  
Małgorzata Miastkowska ◽  
Agnieszka Kulawik-Pióro ◽  
Mariola Szczurek
Keyword(s):  
Aloe Vera ◽  
Protective Layer ◽  
Skin Condition ◽  
Sensory Properties ◽  
Skin Regeneration ◽  
Scattering Method ◽  
Promising Alternative ◽  
Burn Wounds ◽  
Dynamic Light Scattering Method ◽  
Nanoemulsion Gel

Background: Despite the variety of treatment methods for wounds and scars after burns, there are still few effective preparations that can be used in a non-invasive therapy. Recent years have seen significant development of nanomedicine and nanotechnology in the treatment of infection in burn wounds. Proposal: The aim of this work was to develop a formula of a nanoemulsion gel for skin regeneration after burns, and to compare its rheological and sensory properties, as well as the effectiveness of post-burn skin regeneration with preparations available on the market. Methods: At the first stage of studies the composition and parameters of the preparation of sea buckthorn oil-based O/W (oil-in-water) nanoemulsion containing hyaluronic acid and aloe vera gel, as the active ingredients were optimized. Then, the nanoemulsion was added to the gel matrix composed of carbomer (1%) and water which resulted in receiving nanoemulgel. The physicochemical parameters of the obtained samples were characterized by means of dynamic light scattering method and scanning electron microscope. Rheological, sensory and influence on skin condition analysis was conducted for selected market products and developed nanoemulgel. Results: Nanoemulsion gel (d = 211 ± 1.4 nm, polydispersity index (PDI) = 0.205 ± 0.01) was characterized by semi-solid, non-sticky consistency, porous structure, law viscosity, good “primary” and “secondary” skin feelings and pleasant sensorical properties. It improves the condition of burned skin by creating a protective layer on the skin and increasing the hydration level. Conclusion: Due to the fact that the obtained nanoemulsion gel combines the advantages of an emulsion and a gel formulation, it can be a promising alternative to medical cosmetics available on the market, as a form of formulation used in skin care after burns.

scholarly journals Non-equilibrium surface tension of the vapour-liquid interface of active Lennard-Jones particles

2017 ◽  
Vol 147 (8) ◽  
pp. 084902 ◽  
Author(s):  
Siddharth Paliwal ◽  
Vasileios Prymidis ◽  
Laura Filion ◽  
Marjolein Dijkstra
Keyword(s):  
Surface Tension ◽  
Liquid Interface ◽  
Equilibrium Surface ◽  
Lennard Jones ◽  
Equilibrium Surface Tension ◽  
Non Equilibrium
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