scholarly journals Polymer–Colloid Complexes Based on Cationic Imidazolium Amphiphile, Polyacrylic Acid and DNA Decamer

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2363
Author(s):  
Darya A. Kuznetsova ◽  
Dinar R. Gabdrakhmanov ◽  
Denis M. Kuznetsov ◽  
Svetlana S. Lukashenko ◽  
Valery M. Zakharov ◽  
...  
Keyword(s):  
Hela Cells ◽  
Polyacrylic Acid ◽  
Hydrophobic Interactions ◽  
Physicochemical Characteristics ◽  
Hydrodynamic Diameter ◽  
Electrostatic Forces ◽  
Flow Cytometry Data ◽  
Low Degree ◽  
Polymer Colloid ◽  
A Minor

The solution behavior and physicochemical characteristics of polymer–colloid complexes based on cationic imidazolium amphiphile with a dodecyl tail (IA-12) and polyacrylic acid (PAA) or DNA decamer (oligonucleotide) were evaluated using tensiometry, conductometry, dynamic and electrophoretic light scattering and fluorescent spectroscopy and microscopy. It has been established that PAA addition to the surfactant system resulted in a ca. 200-fold decrease in the aggregation threshold of IA-12, with the hydrodynamic diameter of complexes ranging within 100–150 nm. Electrostatic forces are assumed to be the main driving force in the formation of IA-12/PAA complexes. Factors influencing the efficacy of the complexation of IA-12 with oligonucleotide were determined. The nonconventional mode of binding with the involvement of hydrophobic interactions and the intercalation mechanism is probably responsible for the IA-12/oligonucleotide complexation, and a minor contribution of electrostatic forces occurred. The latter was supported by zeta potential measurements and the gel electrophoresis technique, which demonstrated the low degree of charge neutralization of the complexes. Importantly, cellular uptake of the IA-12/oligonucleotide complex was confirmed by fluorescence microscopy and flow cytometry data on the example of M-HeLa cells. While single IA-12 samples exhibit roughly similar cytotoxicity, IA-12–oligonucleotide complexes show a selective effect toward M-HeLa cells (IC50 1.1 µM) compared to Chang liver cells (IC50 23.1 µM).

Controlled-Atmosphere Storage of Pork Under Carbon Dioxide

1994 ◽  
Vol 57 (12) ◽  
pp. 1088-1093 ◽  
Author(s):  
R. A. HOLLEY ◽  
P. DELAQUIS ◽  
N. RODRIGUE ◽  
G. DOYON ◽  
J. GAGNON ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Shelf Life ◽  
Weight Ratio ◽  
Storage Period ◽  
Physicochemical Characteristics ◽  
Minor Effect ◽  
Psychrotrophic Bacteria ◽  
Physical Measurements ◽  
A Minor ◽  
Atmosphere Storage

Fresh pork loin slices were packaged under three different anoxic atmospheres (100% N2, 100% CO2 and 50% N2 + 50% CO2) and kept at two storage temperatures (−1°C and 4°C) and two pressures (1.0 and 1.2 atm.) in reusable, gas impermeable metal boxes. A gas headspace to meat weight ratio of >31 per kg was maintained. Carbon dioxide concentrations were unchanged (controlled) during storage. Microbiological, biochemical and physical measurements were made during the 3-week storage period. While atmospheric pressure did not have a significant impact on shelf-life, samples stored at −1°C were satisfactory at 21 days in both CO2 treatments. Samples under N2 did not fare so well, showing higher levels of psychrotrophic bacteria after 18 days at −1°C and 14 days at 4°C. Samples kept in N2 at 4°C were spoiled within 2 weeks. Bacterial growth was slowest under 100% CO2, but samples stored under 50%–50% N2–CO2 at 4°C were also observed to be in good microbiological condition at 21 days of storage. Use of CO2-containing atmospheres provided more than 7 extra days of shelf-life at 4°C over that attainable under 100% N2. Shelf-life at −1°C was improved by 3 to 4 days over that at 4°C. Except for the length of time in storage, treatments had only a minor effect on pH, color, water holding capacity and shear force. These physicochemical characteristics were not factors which limited shelf-life.

Observations on the mechanical precipitation of oxy Hb S and other mutants

Blood ◽  
1975 ◽  
Vol 45 (3) ◽  
pp. 377-386
Author(s):  
EF Jr Roth ◽  
D Elbaum ◽  
RL Nagel
Keyword(s):  
Hydrophobic Interactions ◽  
Carbon Chain ◽  
Precipitation Rate ◽  
Carbon Chain Length ◽  
Mechanical Instability ◽  
Protective Capacity ◽  
Cold Temperatures ◽  
Sh Group ◽  
Hb S ◽  
A Minor

Oxyhemoglobin S exhibits greater mechanical instability than oxyhemoglobin A. The rate of precipitation of Hb S when agitated by vortexing depends upon the geometry of the tube, the volume of the hemoglobin solution, and the concentration of hemoglobin. The rate of precipitation is inversely related to concentration. Precipitation is inhibited by temperatures near 4 degrees C and alkylureas whose protective capacity is approximately proportional to the carbon chain length of the alkyl group. Blocking the beta93 -SH group with parahydroxymercuribenzoate has only a small enhancing effect on the precipitation rate. Other mutants such as Hb Gun Hill, Leiden, (both heat unstable), and C-HARLEM are also unstable. In the case of C- HARLEM, the precipitation rate is greater than that for Hb S. The heat- unstable mutants are not as well protected by cold temperatures or alkyl ureas. D2O has only a minor stabilizing effect on hemoglobin S, but NaCl and related salts markedly enhance precipitation at concentrations of 0.5 M. It is concluded that mechanical instability of oxyhemoglobins is a multifactorial process involving surface denaturation, pH, ionic strength, hydrophobic interactions, protein conformation, and primary protein structure. This phenomenon will require more extensive investigation.

Poly(ethylene glycol)-graft-poly(vinyl acetate) single-chain nanoparticles for the encapsulation of small molecules

2017 ◽  
Vol 19 (6) ◽  
pp. 4553-4559 ◽  
Author(s):  
Arianna Bartolini ◽  
Paolo Tempesti ◽  
Claudio Resta ◽  
Debora Berti ◽  
Johan Smets ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Small Molecules ◽  
Vinyl Acetate ◽  
Hydrodynamic Radius ◽  
Hydrophobic Interactions ◽  
Single Chain ◽  
Poly Ethylene Glycol ◽  
Low Degree ◽  
Poly Ethylene

Amphiphilic poly(ethylene glycol)-graft-poly(vinyl acetate) copolymers with a low degree of grafting undergo self-folding in water driven by hydrophobic interactions, resulting in single-chain nanoparticles (SCNPs) possessing a hydrodynamic radius of about 10 nm.

Particulate glycogen of mammalian liver: specificity in binding phosphorylase and glycogen synthase

1992 ◽  
Vol 70 (7) ◽  
pp. 523-527 ◽  
Author(s):  
Alexander Vardanis
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Glycogen Phosphorylase ◽  
Hydrophobic Interactions ◽  
Glycogen Synthase ◽  
Early Period ◽  
Glycogen Particle ◽  
Molecular Weights ◽  
Glycogen Deposition ◽  
A Minor

The glycogen particle – glycogen metabolizing enzyme complex was investigated to gain some understanding of its physiological significance. Fractionations of populations of particles from mouse liver were carried out utilising open column and high performance liquid chromatography, and based either on the molecular weight of the particles or the hydrophobic interactions of the glycogen-associated proteins. The activities of glycogen phosphorylase and glycogen synthase were measured in these fractions. Fractionations were of tissue in different stages of glycogen deposition or mobilization. In animals fed ad libitum, glycogen synthase was associated with the whole spectrum of molecular weights, while the glycogen phosphorylase distribution was skewed in favour of the lower molecular weight species. Under conditions of glycogen mobilization, the phosphorylase distribution changed to include all molecular weights. The hydrophobic interaction separations demonstrated that glycogen synthase binds to a specific subpopulation of particles that is a minor proportion of the total. In general, there was a direct relationship of the total amount of phosphorylase and synthase bound during periods of mobilization and deposition, respectively. Two notable exceptions were the large amounts of glucose-6-P dependent synthase present during the early period of glycogen mobilization and the high amounts of active phosphorylase appearing shortly after food withdrawal, in spite of interim glycogen deposition from presumably already ingested food.Key words: glycogen particle, glycogenolysis, glycogenesis, glycogen phosphorylase, glycogen synthase.

Crosslink Distribution and Interfacial Adhesion in Vulcanized Blends of NR and NBR

1990 ◽  
Vol 63 (4) ◽  
pp. 503-515 ◽  
Author(s):  
Andrew J. Tinker
Keyword(s):  
Interfacial Adhesion ◽  
Cohesive Failure ◽  
Preferential Distribution ◽  
Low Degree ◽  
A Minor

Abstract In contrast to expectations from rheometer studies of vulcanization behavior, the NMR technique has demonstrated that blends of NR and NBR vulcanized with sulfur/TMTM show a marked distribution of crosslinks in favor of the NR phase. The presence of even a minor proportion of NBR is sufficient to reduce the degree of vulcanization of the NR phase below levels deemed to be technologically necessary. Replacing the sulfur with a bis-alkylphenol disulfide reduces the degree of preferential distribution of crosslinks substantially. Interpretation of differential-swelling data for the blends on the basis of the swelling expected from a single polymer vulcanized with the same level of curatives as added to the blend gives the impression that the blends are lacking in interfacial adhesion. The interpretation enabled by the NMR estimates of degrees of crosslinking for the phases within the blends demonstrates that there is no lack of interfacial adhesion in blends of NR and NBR having a low acrylonitrile content, although blends containing a minor proportion of NR and vulcanized with sulfur/TMTM may show cohesive failure of the NR phase when the NBR phase is highly swollen due to the low degree of crosslinking of the NR.

scholarly journals Encapsulation of Berberis vulgaris Anthocyanins into Nanoliposome Composed of Rapeseed Lecithin: A Comprehensive Study on Physicochemical Characteristics and Biocompatibility

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 492
Author(s):  
Mina Homayoonfal ◽  
Seyed Mohammad Mousavi ◽  
Hossein Kiani ◽  
Gholamreza Askari ◽  
Stephane Desobry ◽  
...  
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Hydrophobic Interactions ◽  
Hydrocarbon Chain ◽  
Physicochemical Characteristics ◽  
Narrow Particle Size Distribution ◽  
In Vitro Biocompatibility ◽  
Comprehensive Study ◽  
Rapeseed Lecithin

In the present study, nanoliposomes composed of rapeseed lecithin were used for the encapsulation of anthocyanin compounds (AC). The nanoliposomes were prepared using hydration and ultrasound combined method, and the effect of AC concentration (4.5, 6.75, 9% w/w) on the characteristics of nanoliposomes including particle size, polydispersity index (PDI), zeta potential, and the encapsulation efficiency (EE) of nanoliposomes with and without AC were studied. The results suggested the fabricated nanoliposomes had a size range of 141–196 nm, negative zeta potential and narrow particle size distribution. Further, the samples containing 9% extract had the maximum EE (43%). The results showed elevation of AC concentration resulted in increased particle size, PDI, EE, and surface charge of nanoparticles. The presence of AC extract led to diminished membrane fluidity through the hydrophobic interactions with the hydrocarbon chain of fatty acids. TEM images suggested that the nanoliposomes were nearly spherical and the AC caused their improved sphericity. Further, in vitro biocompatibility tests for human mesenchymal (MSC) and fibroblast (FBL) cells indicated nanoparticles were not toxic. Specifically, the best formulations with the maximum compatibility and bioavailability for MSC and FBL cells were AC-loaded nanoliposomes with concentrations of 0.5 mL/mg and 10.3 mL/µg and, respectively.

scholarly journals Surfactant Effect on the Physicochemical Characteristics of Solid Lipid Nanoparticles Based on Pillar[5]arenes

2022 ◽  
Vol 23 (2) ◽  
pp. 779
Author(s):  
Anastasia Nazarova ◽  
Luidmila Yakimova ◽  
Darya Filimonova ◽  
Ivan Stoikov
Keyword(s):  
Solid Lipid Nanoparticles ◽  
Physicochemical Characteristics ◽  
Lipid Nanoparticles ◽  
Spherical Particles ◽  
Hydrodynamic Diameter ◽  
Solid Lipid ◽  
Molecular Scale ◽  
Dodecyltrimethylammonium Chloride ◽  
First Time ◽  
Average Hydrodynamic Diameter

Novel monosubstituted pillar[5]arenes containing both amide and carboxyl functional groups were synthesized. Solid lipid nanoparticles based on the synthesized macrocycles were obtained. Formation of spherical particles with an average hydrodynamic diameter of 250 nm was shown for pillar[5]arenes containing N-(amidoalkyl)amide fragments regardless of their concentration. It was established that pillar[5]arene containing N-alkylamide fragments can form spherical particles with two different sizes (88 and 223 nm) depending on its concentration. Mixed solid lipid nanoparticles based on monosubstituted pillar[5]arenes and surfactant (dodecyltrimethylammonium chloride) were obtained for the first time. The surfactant made it possible to level the effect of the macrocycle concentration. It was found that various types of aggregates are formed depending on the macrocycle/surfactant ratio. Changing the macrocycle/surfactant ratio allows to control the charge of the particles surface. This controlled property will lead to the creation of molecular-scale porous materials that selectively interact with various types of substrates, including biopolymers.

scholarly journals Liposomes Loaded with Cisplatin and Magnetic Nanoparticles: Physicochemical Characterization, Pharmacokinetics, and In-Vitro Efficacy

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2272 ◽  
Author(s):  
Alfonso Toro-Cordova ◽  
Mario Flores-Cruz ◽  
Jaime Santoyo-Salazar ◽  
Ernesto Carrillo-Nava ◽  
Rafael Jurado ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Hela Cells ◽  
Physicochemical Characterization ◽  
Pharmacokinetic Profile ◽  
Physicochemical Characteristics ◽  
Cholesterol Concentration ◽  
Pharmacokinetic Studies ◽  
Reverse Phase ◽  
Ζ Potential

With the aim improving drug delivery, liposomes have been employed as carriers for chemotherapeutics achieving promising results; their co-encapsulation with magnetic nanoparticles is evaluated in this work. The objective of this study was to examine the physicochemical characteristics, the pharmacokinetic behaviour, and the efficacy of pegylated liposomes loaded with cisplatin and magnetic nanoparticles (magnetite) (Cis-MLs). Cis-MLs were prepared by a modified reverse-phase evaporation method. To characterize their physicochemical properties, an evaluation was made of particle size, ζ-potential, phospholipid and cholesterol concentration, phase transition temperature (Tm), the encapsulation efficiency of cisplatin and magnetite, and drug release profiles. Additionally, pharmacokinetic studies were conducted on normal Wistar rats, while apoptosis and the cytotoxic effect were assessed with HeLa cells. We present a method for simultaneously encapsulating cisplatin at the core and also embedding magnetite nanoparticles on the membrane of liposomes with a mean vesicular size of 104.4 ± 11.5 nm and a ζ-potential of −40.5 ± 0.8 mV, affording a stable formulation with a safe pharmacokinetic profile. These liposomes elicited a significant effect on cell viability and triggered apoptosis in HeLa cells.

Complex Formation of Polyacrylic Acid with Surfactants of Different Hydrophobicity

2015 ◽  
Vol 752-753 ◽  
pp. 212-216
Author(s):  
Sagdat Tazhibayeva ◽  
Kuanyshbek Musabekov ◽  
Zhenis Kusainova ◽  
Ardak Sapieva ◽  
Nurlan Musabekov
Keyword(s):  
Complex Formation ◽  
Polyacrylic Acid ◽  
Hydrophobic Interactions ◽  
Reduced Viscosity ◽  
Hydrophilic Lipophilic Balance ◽  
Alkylammonium Salts ◽  
Living Organisms ◽  
Polymer Surfactant ◽  
Degree Of Purification ◽  
Polar Parts

Complex formation processes of polyelectrolytes with surfactant ions are close model to protein - lipid interactions in living organisms. Furthermore, polymer – surfactant complexes are widely used as stabilizers of industrial dispersions and structurants of soil. When using the polymer-surfactant complexes the hydrophilic-lipophilic balance has the great importance. The interaction of polyacrylic acid with alkylammonium salts of different hydrophobicity: cetyltrimethylammonium bromide, dilaurildimethylammonium bromide and dioctadecyldimethylammonium chloride was studied by potentiometry, spectrophotometry, viscometry and electrophoresis methods. It was established that the complex formation of polyacrylic acid with cationic surfactants is carried out due to the electrostatic interaction between carboxyl groups of the polymer and cations of surfactants, which stabilized by hydrophobic interactions between their non-polar parts. The phenomenon of hysteresis in the change of the reduced viscosity of system surfactant /polyacrylic acid with temperature variation in the range of 20-60 °C was found. The possibility of using the complex formation process for water purification from CTAB has been shown. The degree of purification is 99.6-99.8%.

scholarly journals Novel 4-Arm Poly(Ethylene Glycol)-Block-Poly(Anhydride-Esters) Amphiphilic Copolymer Micelles Loading Curcumin: Preparation, Characterization, and In Vitro Evaluation

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Li Lv ◽  
Yuanyuan Shen ◽  
Min Li ◽  
Xiaofen Xu ◽  
Mingna Li ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Hela Cells ◽  
Drug Loading ◽  
Amphiphilic Copolymer ◽  
Phase Cell ◽  
Hydrodynamic Diameter ◽  
Dependent Manner ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene

A novel 4-arm poly(ethylene glycol)-block-poly(anhydride-esters) amphiphilic copolymer (4-arm PEG-b-PAE) was synthesized by esterization of 4-arm poly(ethylene glycol) and poly(anhydride-esters) which was obtained by melt polycondensation ofα-,ω-acetic anhydride terminated poly(L-lactic acid). The obtained 4-arm PEG-b-PAE was characterized by1H-NMR and gel permeation chromatography. The critical micelle concentration of 4-arm PEG-b-PAE was 2.38 μg/mL. The curcumin-loaded 4-arm PEG-b-PAE micelles were prepared by a solid dispersion method and the drug loading content and encapsulation efficiency of the micelles were 7.0% and 85.2%, respectively. The curcumin-loaded micelles were spherical with a hydrodynamic diameter of 151.9 nm. Curcumin was encapsulated within 4-arm PEG-b-PAE micelles amorphously and released from the micelles, faster in pH 5.0 than pH 7.4, presenting one biphasic drug release pattern with rapid release at the initial stage and slow release later. The hemolysis rate of the curcumin-loaded 4-arm PEG-b-PAE micelles was 3.18%, which was below 5%. The IC50value of the curcumin-loaded micelles against Hela cells was 10.21 μg/mL, lower than the one of free curcumin (25.90 μg/mL). The cellular uptake of the curcumin-loaded micelles in Hela cell increased in a time-dependent manner. The curcumin-loaded micelles could induce G2/M phase cell cycle arrest and apoptosis of Hela cells.

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