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1.
Molecules ; 29(13)2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38999144

ABSTRACT

This study assessed the nutritional profile of camellia oil through its fatty acid composition, highlighting its high oleic acid content (81.4%), followed by linoleic (7.99%) and palmitic acids (7.74%), demonstrating its excellence as an edible oil source. The impact of beeswax (BW) and glycerol monolaurate (GML) on camellia oil oleogels was investigated, revealing that increasing BW or GML concentrations enhanced hardness and springiness, with 10% BW oleogel exhibiting the highest hardness and springiness. FTIR results suggested that the structure of the oleogels was formed by interactions between molecules without altering the chemical composition. In biscuits, 10% BW oleogel provided superior crispness, expansion ratio, texture, and taste, whereas GML imparted a distinct odor. In sausages, no significant differences were observed in color, water retention, and pH between the control and replacement groups; however, the BW group scored higher than the GML group in the sensory evaluation. The findings suggest that the BW oleogel is an effective fat substitute in biscuits and sausages, promoting the application of camellia oil in food products.


Subject(s)
Camellia , Laurates , Monoglycerides , Organic Chemicals , Plant Oils , Waxes , Camellia/chemistry , Waxes/chemistry , Plant Oils/chemistry , Laurates/chemistry , Organic Chemicals/chemistry , Organic Chemicals/analysis , Monoglycerides/chemistry , Meat Products/analysis , Taste , Fatty Acids/chemistry , Fatty Acids/analysis
2.
Sci Rep ; 14(1): 15831, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38982188

ABSTRACT

2-Hydroxyoleic acid (2-OHOA) has gained attention as a membrane lipid therapy (MLT) anti-cancer drug. However, in the viewpoint of anti-cancer drug, 2-OHOA shows poor water solubility and its effectiveness still has space for improvement. Thus, this study aimed to overcome the problems by formulating 2-OHOA into liposome dosage form. Furthermore, in the context of MLT reagents, the influence of 2-OHOA on the biophysical properties of the cytoplasmic membrane remains largely unexplored. To bridge this gap, our study specifically focused the alterations in cancer cell membrane fluidity and lipid packing characteristics before and after treatment. By using a two-photon microscope and the Laurdan fluorescence probe, we noted that liposomes incorporating 2-OHOA induced a more significant reduction in cancer cell membrane fluidity, accompanied by a heightened rate of cellular apoptosis when compared to the non-formulated 2-OHOA. Importantly, the enhanced efficacy of 2-OHOA within the liposomal formulation demonstrated a correlation with its endocytic uptake mechanism. In conclusion, our findings underscore the significant influence of 2-OHOA on the biophysical properties of cancer plasma membranes, emphasizing the potential of liposomes as an optimized delivery system for 2-OHOA in anti-cancer therapy.


Subject(s)
Cell Membrane , Liposomes , Membrane Fluidity , Liposomes/chemistry , Humans , Cell Membrane/metabolism , Cell Membrane/chemistry , Cell Membrane/drug effects , Membrane Fluidity/drug effects , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Apoptosis/drug effects , Laurates/chemistry , Microscopy, Fluorescence, Multiphoton , Cell Line, Tumor , Neoplasms/drug therapy , Neoplasms/pathology , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Oleic Acids/chemistry , Fluorescent Dyes/chemistry
3.
Methods Enzymol ; 700: 105-126, 2024.
Article in English | MEDLINE | ID: mdl-38971597

ABSTRACT

Hyperspectral imaging is a technique that captures a three-dimensional array of spectral information at each spatial location within a sample, enabling precise characterization and discrimination of biological structures, materials, and chemicals, based on their unique spectral features. Nowadays most commercially available confocal microscopes allow hyperspectral imaging measurements, providing a valuable source of spatially resolved spectroscopic data. Spectral phasor analysis quantitatively and graphically transforms the fluorescence spectra at each pixel of a hyperspectral image into points in a polar plot, offering a visual representation of the spectral characteristics of fluorophores within the sample. Combining the use of environmentally sensitive dyes with phasor analysis of hyperspectral images provides a powerful tool for measuring small changes in lateral membrane heterogeneity. Here, we focus on applications of spectral phasor analysis for the probe LAURDAN on model membranes to resolve packing and hydration. The method is broadly applicable to other dyes and to complex systems such as cell membranes.


Subject(s)
Fluorescent Dyes , Spectrometry, Fluorescence , Fluorescent Dyes/chemistry , Spectrometry, Fluorescence/methods , Microscopy, Confocal/methods , Laurates/chemistry , Cell Membrane/chemistry , Cell Membrane/metabolism , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Lipid Bilayers/chemistry
4.
Food Chem ; 455: 139959, 2024 Oct 15.
Article in English | MEDLINE | ID: mdl-38850980

ABSTRACT

The Glycerol monolaurate (GML) oleogel was induced using Camellia oil by slowly raising the temp to the melting point (MP) of GML. Whey protein isolate (WPI) solution with different ratios was composited with GML oleogel by emulsion template methods, forming dense spines and honeycomb-like networks and impressed with an adjustable composite structure. Textural results showed that compared with single GML-based oleogels, the GML/WPI composite oleogels had the advantages of high hardness and molding, and structural stability. The composite oleogels had moderate thermal stability and maximal oil binding (96.36%). In particular, as up to 6 wt% GML/WPI, its modulus apparent viscosity was significantly increased in rheology and similar to commercial fats. Moreover, it achieved the highest release of FFA (64.07%) and the synergy provided a lipase substrate and reduced the body's burden. The resulting composite oleogel also showed intermolecular hydrogen bonding and van der Waals force interactions. These findings further enlarge the application in the plant and animal-based combined of fat substitutes, delivery of bioactive molecules, etc., with the desired physical and functional properties according to different proportions.


Subject(s)
Digestion , Laurates , Monoglycerides , Organic Chemicals , Whey Proteins , Whey Proteins/chemistry , Laurates/chemistry , Monoglycerides/chemistry , Organic Chemicals/chemistry , Viscosity , Rheology , Models, Biological , Camellia/chemistry , Animals , Lipase/chemistry , Lipase/metabolism , Fat Substitutes/chemistry
5.
Biophys Chem ; 311: 107269, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38815545

ABSTRACT

Reverse micelles (RMs) are spontaneously organizing nanobubbles composed of an organic solvent, surfactants, and an aqueous phase that can encapsulate biological macromolecules for various biophysical studies. Unlike other RM systems, the 1-decanoyl-rac-glycerol (10MAG) and lauryldimethylamine-N-oxide (LDAO) surfactant system has proven to house proteins with higher stability than other RM mixtures with little sensitivity to the water loading (W0, defined by the ratio of water to surfactant). We investigated this unique property by encapsulating three model proteins - cytochrome c, myoglobin, and flavodoxin - in 10MAG/LDAO RMs and applying a variety of experimental methods to characterize this system's behavior. We found that this surfactant system differs greatly from the traditional, spherical, monodisperse RM population model. 10MAG/LDAO RMs were discovered to be oblate ellipsoids at all conditions, and as W0 was increased, surfactants redistributed to form a greater number of increasingly spherical ellipsoidal particles with pools of more bulk-like water. Proteins distinctively influence the thermodynamics of the mixture, encapsulating at their optimal RM size and driving protein-free RM sizes to scale accordingly. These findings inform the future development of similarly malleable encapsulation systems and build a foundation for application of 10MAG/LDAO RMs to analyze biological and chemical processes under nanoscale confinement.


Subject(s)
Glycerol , Micelles , Myoglobin , Surface-Active Agents , Myoglobin/chemistry , Surface-Active Agents/chemistry , Glycerol/chemistry , Cytochromes c/chemistry , Flavodoxin/chemistry , Laurates/chemistry , Thermodynamics , Water/chemistry , Dimethylamines
6.
Food Chem ; 453: 139689, 2024 Sep 30.
Article in English | MEDLINE | ID: mdl-38781902

ABSTRACT

In this study, based on the discovery of thymol/glycerol monolaurate (GML) eutectic solvent, we studied the effect of GML as a multi-functional component (ripening inhibitor and antibacterial agent) on the formation, stability and antibacterial activity of eutectic nanoemulsions, and investigated the preservation of nanoemulsion in fresh pork. These results indicated that the formation of eutectic solvent was due to the hydrogen bonding between thymol and GML in the molten state. And eutectic nanoemulsions prepared with medium GML concentrations (20%, 40%, and 60%) of eutectic solvents as oil phases had small droplet diameters (<150 nm), exhibited sustained-release characteristics, and had excellent physicochemical stability. Moreover, the addition of GML enhanced the antibacterial activity of thymol nanoemulsion against S. aureus. as seen by their ability to inhibit affect formation more effectively. Treatment of fresh pork with optimized eutectic nanoemulsions (40% thymol/60% GML) extended its shelf life during refrigeration, which was mainly attributed to the ability of the encapsulated essential oil to inhibit microbial growth and lipid oxidation. These results provide a novel strategy to control Ostwald ripening and maintain the high antibacterial activity of thymol in nanoemulsion-based delivery systems.


Subject(s)
Anti-Bacterial Agents , Emulsions , Laurates , Monoglycerides , Staphylococcus aureus , Thymol , Thymol/chemistry , Thymol/pharmacology , Emulsions/chemistry , Emulsions/pharmacology , Laurates/chemistry , Laurates/pharmacology , Monoglycerides/chemistry , Monoglycerides/pharmacology , Swine , Animals , Staphylococcus aureus/drug effects , Staphylococcus aureus/growth & development , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Food Preservation
7.
J Photochem Photobiol B ; 250: 112833, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38141326

ABSTRACT

The solvatochromic dye Laurdan is widely used in sensing the lipid packing of both model and biological membranes. The fluorescence emission maximum shifts from about 440 nm (blue channel) in condensed membranes (So) to about 490 nm (green channel) in the liquid-crystalline phase (Lα). Although the fluorescence intensity based generalized polarization (GP) is widely used to characterize lipid membranes, the fluorescence lifetime of Laurdan, in the blue and the green channel, is less used for that purpose. Here we explore the correlation between GP and fluorescence lifetimes by spectroscopic measurements on the So and Lα phases of large unilamellar vesicles of DMPC and DPPC. A positive correlation between GP and the lifetimes is observed in each of the optical channels for the two lipid phases. Microfluorimetric determinations on giant unilamellar vesicles of DPPC and DOPC at room temperature are performed under linearly polarized two-photon excitation to disentangle possible subpopulations of Laurdan at a scale below the optical resolution. Fluorescence intensities, GP and fluorescence lifetimes depend on the angle between the orientation of the linear polarization of the excitation light and the local normal to the membrane of the optical cross-section. This angular variation depends on the lipid phase and the emission channel. GP and fluorescence intensities in the blue and green channel in So and in the blue channel in Lα exhibit a minimum near 90o. Surprisingly, the intensity in the green channel in Lα reaches a maximum near 90o. The fluorescence lifetimes in the two optical channels also reach a pronounced minimum near 90o in So and Lα, apart from the lifetime in the blue channel in Lα where the lifetime is short with minimal angular variation. To our knowledge, these experimental observations are the first to demonstrate the existence of a bent conformation of Laurdan in lipid membranes, as previously suggested by molecular dynamics calculations.


Subject(s)
Laurates , Unilamellar Liposomes , Cell Membrane , Laurates/analysis , Laurates/chemistry , 2-Naphthylamine/chemistry , Fluorescent Dyes/chemistry , Fluorescence Polarization
8.
Biochim Biophys Acta Biomembr ; 1865(7): 184176, 2023 10.
Article in English | MEDLINE | ID: mdl-37328024

ABSTRACT

Cells are constantly adapting to maintain their identity in response to the surrounding media's temporal and spatial heterogeneity. The plasma membrane, which participates in the transduction of external signals, plays a crucial role in this adaptation. Studies suggest that nano and micrometer areas with different fluidities at the plasma membrane change their distribution in response to external mechanical signals. However, investigations linking fluidity domains with mechanical stimuli, specifically matrix stiffness, are still in progress. This report tests the hypothesis that the stiffness of the extracellular matrix can modify the equilibrium of areas with different order in the plasma membrane, resulting in changes in overall membrane fluidity distribution. We studied the effect of matrix stiffness on the distribution of membrane lipid domains in NIH-3 T3 cells immersed in matrices of varying concentrations of collagen type I, for 24 or 72 h. The stiffness and viscoelastic properties of the collagen matrices were characterized by rheometry, fiber sizes were measured by Scanning Electron Microscopy (SEM) and the volume occupied by the fibers by second harmonic generation imaging (SHG). Membrane fluidity was measured using the fluorescent dye LAURDAN and spectral phasor analysis. The results demonstrate that an increase in collagen stiffness alters the distribution of membrane fluidity, leading to an increasing amount of the LAURDAN fraction with a high degree of packing. These findings suggest that changes in the equilibrium of fluidity domains could represent a versatile and refined component of the signal transduction mechanism for cells to respond to the highly heterogeneous matrix structural composition. Overall, this study sheds light on the importance of the plasma membrane's role in adapting to the extracellular matrix's mechanical cues.


Subject(s)
Laurates , Membrane Fluidity , Cell Membrane/metabolism , Laurates/chemistry , Collagen/metabolism
9.
Methods Appl Fluoresc ; 11(1)2022 Nov 09.
Article in English | MEDLINE | ID: mdl-36252561

ABSTRACT

Hyperspectral imaging (HSI) is a paramount technique in biomedical science, however, unmixing and quantification of each spectral component is a challenging task. Traditional unmixing relies on algorithms that need spectroscopic parameters from the fluorescent species in the sample. The phasor-based multi-harmonic unmixing method requires only the empirical measurement of the pure species to compute the pixel-wise photon fraction of every spectral component. Using simulations, we demonstrate the feasibility of the approach for up to 5 components and explore the use of adding a 6th unknown component representing autofluorescence. The simulations show that the method can be successfully used in typical confocal imaging experiments (with pixel photon counts between 101and 103). As a proof of concept, we tested the method in living cells, using 5 common commercial dyes for organelle labeling and we easily and accurately separate them. Finally, we challenged the method by introducing a solvatochromic probe, 6-Dodecanoyl-N,N-dimethyl-2-naphthylamine (LAURDAN), intended to measure membrane dynamics on specific subcellular membrane-bound organelles by taking advantage of the linear combination between the organelle probes and LAURDAN. We succeeded in monitoring the membrane order in the Golgi apparatus, Mitochondria, and plasma membrane in the samein-vivocell and quantitatively comparing them. The phasor-based multi-harmonic unmixing method can help expand the outreach of HSI and democratize its use by the community for it does not require specialized knowledge.


Subject(s)
2-Naphthylamine , Laurates , Laurates/analysis , Laurates/chemistry , 2-Naphthylamine/analysis , 2-Naphthylamine/chemistry , Microscopy, Fluorescence/methods , Cell Membrane
10.
Am J Physiol Lung Cell Mol Physiol ; 322(2): L191-L203, 2022 02 01.
Article in English | MEDLINE | ID: mdl-34851730

ABSTRACT

By coating the alveolar air-liquid interface, lung surfactant overwhelms surface tension forces that, otherwise, would hinder the lifetime effort of breathing. Years of research have provided a picture of how highly hydrophobic and specialized proteins in surfactant promote rapid and efficient formation of phospholipid-based complex three-dimensional films at the respiratory surface, highly stable under the demanding breathing mechanics. However, recent evidence suggests that the structure and performance of surfactant typically isolated from bronchoalveolar lung lavages may be far from that of nascent, still unused, surfactant as freshly secreted by type II pneumocytes into the alveolar airspaces. In the present work, we report the isolation of lung surfactant from human amniotic fluid (amniotic fluid surfactant, AFS) and a detailed description of its composition, structure, and surface activity in comparison to a natural surfactant (NS) purified from porcine bronchoalveolar lavages. We observe that the lipid/protein complexes in AFS exhibit a substantially higher lipid packing and dehydration than in NS. AFS shows melting transitions at higher temperatures than NS and a conspicuous presence of nonlamellar phases. The surface activity of AFS is not only comparable with that of NS under physiologically meaningful conditions but displays significantly higher resistance to inhibition by serum or meconium, agents that inactivate surfactant in the context of severe respiratory pathologies. We propose that AFS may be the optimal model to study the molecular mechanisms sustaining pulmonary surfactant performance in health and disease, and the reference material to develop improved therapeutic surfactant preparations to treat yet unresolved respiratory pathologies.


Subject(s)
Amniotic Fluid/chemistry , Pulmonary Surfactants/chemistry , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Animals , Calorimetry, Differential Scanning , Humans , Hydrophobic and Hydrophilic Interactions , Laurates/chemistry , Lipids/chemistry , Membranes , Swine
11.
Biochim Biophys Acta Biomembr ; 1864(1): 183794, 2022 02 01.
Article in English | MEDLINE | ID: mdl-34627747

ABSTRACT

Employing fluorescence spectroscopy and the membrane-embedded dye Laurdan we experimentally show that linear changes of cell membrane order in the physiological temperature regime are part of broad order-disorder-phase transitions which extend over a much broader temperature range. Even though these extreme temperatures are usually not object of live science research due to failure of cellular functions, our findings help to understand and predict cell membrane properties under physiological conditions as they explain the underlying physics of a broad order-disorder phase transition. Therefore, we analyzed the membranes of various cell lines, red blood cell ghosts and lipid vesicles by spectral decomposition in a custom-made setup in a temperature range from -40 °C to +90 °C. While the generalized polarization as a measure for membrane order of artificial lipid membranes like phosphatidylcholine show sharp transitions as known from calorimetry measurements, living cells in a physiological temperature range do only show linear changes. However, extending the temperature range shows the existence of broad transitions and their sensitivity to cholesterol content, pH and anaesthetic. Moreover, adaptation to culture conditions like decreased temperature and morphological changes like detachment of adherent cells or dendrite growth are accompanied by changes in membrane order as well. The observed changes of the generalized polarization are equivalent to temperature changes dT in the range of +12 K < dT < -6 K.


Subject(s)
Cell Membrane/chemistry , Erythrocyte Membrane/chemistry , Lipids/chemistry , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Cholesterol/chemistry , Fluorescent Dyes/chemistry , Laurates/chemistry , Phase Transition , Phosphatidylcholines/chemistry , Spectrometry, Fluorescence , Thermodynamics
12.
J Food Sci ; 86(10): 4717-4729, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34553787

ABSTRACT

(-)-Epigallocatechin-3-O-gallate(EGCG) was enzymatically modified to enhance the lipophilicity and the antioxidant property. The determination of optimal reaction conditions are as follows: Lipase DF "Amano" 15 and acetone were used as catalyst and solvent, respectively. Equal molar of EGCG and vinyl laurate (1:1); lipase addition of 6.0% (w/w of total substrates); reaction temperature of 50°C and reaction time of 96 h, which obtained the conversion rate of EGCG at 80.1%. The structure of EGCG lauroyl derivatives were 5″-O-lauroyl-EGCG, 3″,5″-2-O-lauroyl-EGCG, and 5',3″,5″-3-O-lauroyl-EGCG, identified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR). Compared with the logP of precursor EGCG (0.69 ± 0.03), the logP of EGCG lauroyl derivatives was 1.37 ± 0.19, 2.27 ± 0.33, and 3.28 ± 0.37, increasing by 0.98, 2.28, and 3.75 times, respectively (p < 0.05), suggesting the grafted fatty acid chains make EGCG derivatives more lipophilic, and the lipid solubility gradually increased as the number of substituents increased. Furthermore, EGCG lauroyl derivatives had excellent lipid oxidation than that of EGCG. The POVs (peroxide values) of soybean oil with mono-, di-, tri-lauroyl EGCG were significantly reduced by 42%, 47%, and 57% than that of EGCG at 21 days, respectively, indicating the antioxidative inhibition of these derivatives decreased with the increase in substituents. This indicates that these derivatives have broad prospects of the antioxidant application while improving their solubility properties in lipophilic environments/high-fat food. Practical Application: The lipophilic esterification reaction of EGCG catalyzed by new catalytic lipase DF "Amano" 15 was carried out in a non-aqueous solvent.Various reaction factors on a higher conversion rate of EGCG lauroyl derivatives were evaluated. The lipophilicity and antioxidant properties of EGCG lauroyl derivatives were much excellent than that of parent EGCG.


Subject(s)
Catechin/analogs & derivatives , Laurates , Vinyl Compounds , Antioxidants/chemistry , Antioxidants/pharmacology , Catechin/chemistry , Catechin/pharmacology , Esterification , Laurates/chemistry , Laurates/pharmacology , Lipid Peroxidation/drug effects , Vinyl Compounds/chemistry , Vinyl Compounds/pharmacology
13.
Biochim Biophys Acta Biomembr ; 1863(12): 183728, 2021 12 01.
Article in English | MEDLINE | ID: mdl-34416246

ABSTRACT

Using LAURDAN fluorescence we observed that water dynamics measured at the interface of DOPC bilayers can be differentially regulated by the presence of crowded suspensions of different proteins (HSA, IgG, Gelatin) and PEG, under conditions where the polymers are not in direct molecular contact with the lipid interface. Specifically, we found that the decrease in water dipolar relaxation at the membrane interface correlates with an increased fraction of randomly oriented (or random coil) configurations in the polymers, as Gelatin > PEG > IgG > HSA. By using the same experimental strategy, we also demonstrated that structural transitions from globular to extended conformations in proteins can induce transitions between lamellar and non-lamellar phases in mixtures of DOPC and monoolein. Independent experiments using Raman spectroscopy showed that aqueous suspensions of polymers exhibiting high proportions of randomly oriented conformations display increased fractions of tetracoordinated water, a configuration that is dominant in ice. This indicates a greater capacity of this type of structure for polarizing water and consequently reducing its chemical activity. This effect is in line with one of the tenets of the Association Induction Hypothesis, which predicts a long-range dynamic structuring of water molecules via their interactions with proteins (or other polymers) showing extended conformations. Overall, our results suggest a crucial role of water in promoting couplings between structural changes in macromolecules and supramolecular arrangements of lipids. This mechanism may be of relevance to cell structure/function when the crowded nature of the intracellular milieu is considered.


Subject(s)
Immunoglobulin G/chemistry , Lipids/chemistry , Serum Albumin, Human/chemistry , Water/chemistry , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Gelatin/chemistry , Glycerides/chemistry , Laurates/chemistry , Molecular Conformation , Phosphatidylcholines/chemistry , Polyethylene Glycols/chemistry , Polymers/chemistry
14.
ACS Appl Mater Interfaces ; 13(25): 29936-29948, 2021 Jun 30.
Article in English | MEDLINE | ID: mdl-34143617

ABSTRACT

Alzheimer's disease (AD) is a major cause of dementia characterized by the overexpression of transmembrane amyloid precursor protein and its neurotoxic byproduct amyloid beta (Aß). A small peptide of considerable hydrophobicity, Aß is aggregation prone catalyzed by the presence of cell membranes, among other environmental factors. Accordingly, current AD mitigation strategies often aim at breaking down the Aß-membrane communication, yet no data is available concerning the cohesive interplay of the three key entities of the cell membrane, Aß, and its inhibitor. Using a lipophilic Laurdan dye and confocal fluorescence microscopy, we observed cell membrane perturbation and actin reorganization induced by Aß oligomers but not by Aß monomers or amyloid fibrils. We further revealed recovery of membrane fluidity by ultrasmall MoS2 quantum dots, also shown in this study as a potent inhibitor of Aß amyloid aggregation. Using discrete molecular dynamics simulations, we uncovered the binding of MoS2 and Aß monomers as mediated by hydrophilic interactions between the quantum dots and the peptide N-terminus. In contrast, Aß oligomers and fibrils were surface-coated by the ultrasmall quantum dots in distinct testudo-like, reverse protein-corona formations to prevent their further association with the cell membrane and adverse effects downstream. This study offers a crucial new insight and a viable strategy for regulating the amyloid aggregation and membrane-axis of AD pathology with multifunctional nanomedicine.


Subject(s)
Amyloid beta-Peptides , Disulfides/chemistry , Membrane Fluidity/physiology , Molybdenum/chemistry , Quantum Dots/chemistry , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Actins/chemistry , Actins/metabolism , Alzheimer Disease , Amyloid beta-Peptides/chemistry , Amyloid beta-Peptides/metabolism , Cell Line, Tumor , Cell Membrane/chemistry , Cell Membrane/metabolism , Humans , Hydrophobic and Hydrophilic Interactions , Laurates/chemistry , Microscopy, Confocal , Molecular Dynamics Simulation , Nanomedicine
15.
Int J Mol Sci ; 22(6)2021 Mar 18.
Article in English | MEDLINE | ID: mdl-33803648

ABSTRACT

Free fatty acids are essential structural components of the cell, and their intracellular distribution and effects on membrane organelles have crucial roles in regulating the metabolism, development, and cell cycle of most cell types. Here we engineered novel fluorescent, polarity-sensitive fatty acid derivatives, with the fatty acid aliphatic chain of increasing length (from 12 to 18 carbons). As in the laurdan probe, the lipophilic acyl tail is connected to the environmentally sensitive dimethylaminonaphthalene moiety. The fluorescence lifetime imaging analysis allowed us to monitor the intracellular distribution of the free fatty acids within the cell, and to simultaneously examine how the fluidity and the microviscosity of the membrane environment influence their localization. Each of these probes can thus be used to investigate the membrane fluidity regulation of the correspondent fatty acid intracellular distribution. We observed that, in PC-12 cells, fluorescent sensitive fatty acid derivatives with increased chain length compartmentalize more preferentially in the fluid regions, characterized by a low microviscosity. Moreover, fatty acid derivatives with the longest chain compartmentalize in lipid droplets and lysosomes with characteristic lifetimes, thus making these probes a promising tool for monitoring lipophagy and related events.


Subject(s)
Fatty Acids/metabolism , Fluorescent Dyes/metabolism , Intracellular Space/metabolism , Membrane Fluidity , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Animals , Fluorescence , Laurates/chemistry , Lysosomes/metabolism , PC12 Cells , Rats , Solvents , Viscosity
16.
J Oleo Sci ; 70(4): 571-580, 2021 Apr 02.
Article in English | MEDLINE | ID: mdl-33692238

ABSTRACT

Polyglycerol monolaurates are generally recognized as safe food additives and are commonly used as food emulsifiers. In this study, the antimicrobial effect of four polyglycerol monolaurates on two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram-negative bacteria (Escherichia. coli and Pseudomonas aeruginosa) were investigated. The minimum inhibitory concentration (MIC) of diglycerol monolaurate (PG2ML), triglycerol monolaurate (PG3ML), hexaglycerol monolaurate (PG6ML), and decaglycerol monolaurate (PG10ML) against S. aureus was 0.16, 0.32, 0.63, and 1.25 mg/mL, respectively. The MIC of PG2ML, PG3ML, PG6ML, and PG10ML against B. subtilis was 0.32, 0.63, 1.25, and 3.75 mg/mL, respectively. No apparent antimicrobial effect of these four polyglycerol monolaurates on E. coli and P. aeruginosa was observed even up to 10.00 mg/mL. The underlying mechanism was investigated by assessing cell membrane permeability, the integrity of cell membrane, and morphology. We concluded that polyglycerol monolaurates might eliminate Gram-positive bacteria by disrupting the cell membrane, thereby increasing cell membrane permeability, releasing the cellular contents, and altering the cell morphology.


Subject(s)
Anti-Bacterial Agents , Emulsifying Agents , Food Additives , Glycerol/pharmacology , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Laurates/pharmacology , Polymers/pharmacology , Cell Membrane/drug effects , Cell Membrane Permeability/drug effects , Dose-Response Relationship, Drug , Drug Resistance, Bacterial , Food Microbiology , Glycerol/chemistry , Gram-Negative Bacteria/cytology , Gram-Positive Bacteria/cytology , Laurates/chemistry , Microbial Sensitivity Tests , Polymers/chemistry , Structure-Activity Relationship
17.
J Sci Food Agric ; 101(13): 5660-5670, 2021 Oct.
Article in English | MEDLINE | ID: mdl-33782974

ABSTRACT

BACKGROUND: Electrospun fibers are a good candidate for the delivery of bioactive compounds in the food industry because of their advantages that include a tunable diameter, high porosity and a high specific surface area. In the present study, we fabricated gelatin/glycerol monolaurate (GML) microemulsion nanofibers by solubilizing GML in Tween-80 followed by mixing with gelatin solution for electrospinning. We hypothesized that the addition of GML microemulsions affects the properties of the gelatin solution and modifies the physical and antimicrobial properties of the resulting nanofibers. RESULTS: Both pure gelatin solution and gelatin/GML microemulsions showed shear-thinning behavior. However, electrospinnability was not affected by the addition of GML microemulsions. A significantly higher average diameter of nanofibers (1147 nm) with 5% GML was observed compared to the gelatin fiber diameter of 560 nm. Fourier transform infrared spectroscopy showed hydrogen bonding between gelatin molecules and GML microemulsions. Thermal analysis and X-ray diffraction indicated an amorphous structure of gelatin/GML microemulsion nanofibers, although a small amount of crystalline GML existed in the nanofibers with high GML content. Gelatin/GML microemulsion nanofibers showed high thermal stability and improved hydrophilicity. Nanofibers with 5% GML (weight with respect to nanofiber) (D64 nanofibers) showed effective antimicrobial activity against Escherichia coli and Staphylococcus aureus. CONCLUSION: Gelatin/GML microemulsion nanofibrous films demonstrate superhydrophilicity and fast dissolution properties as a result of the high surface-to-volume ratio, amorphous structure and improved hydrophilicity of the nanofiber surface. The results indicate the potential application of gelatin/GML microemulsion nanofibrous films as edible antimicrobial food packaging. © 2021 Society of Chemical Industry.


Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Drug Compounding/methods , Laurates/chemistry , Laurates/pharmacokinetics , Monoglycerides/chemistry , Monoglycerides/pharmacokinetics , Escherichia coli , Gelatin/chemistry , Nanofibers/chemistry , Polysorbates/chemistry , Solubility , Staphylococcus aureus/drug effects , Staphylococcus aureus/growth & development
18.
J Food Sci ; 86(3): 867-873, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33580513

ABSTRACT

The solubility of oxygen and its transfer rate to the lipid phase play important roles in lipid oxidation, which affects the taste and safety of lipid-containing foods. In this study, we measured the Henry's constants (solubility) of oxygen for fatty acids, fatty acid esters, and triacylglycerols (TAGs; vegetable oils), as well as the mass transfer coefficients of oxygen at the gas- and water-lipid interfaces. The constants and coefficients were estimated by analyzing the change over time in the oxygen partial pressure or concentration in the closed container based on the mass balance equations of oxygen in the gas and liquid phases. The constant for water obtained by the method used in this study was in agreement with the previously reported value to confirm the validity of the method. The constants for lipids depended on the lipid type, and were higher in the order of fatty acid ester, fatty acid, and TAG. That is, the solubility of oxygen decreased in this order. For all lipids, the constant increased as the number of carbon atoms in the fatty acid chain increased. The constants for fatty acids and their esters were linearly correlated with the enthalpies of evaporation of the lipids. The mass transfer coefficients of oxygen at the gas-liquid interface were on the order of 10-5 m/s for water and methyl dodecanoate and of 10-6 m/s for TAG (rapeseed oil). The coefficient at the water-lipid interface was on the order of 10-6 m/s. PRACTICAL APPLICATION: The Henry's constants (solubility) and transfer rate of oxygen to the lipid phase, fatty acids, fatty acid esters, and triacylglycerols (TAG) were measured. The lipids solubilized three to five times more oxygen than water, and mass transfer rate of oxygen at gas- and water-lipid interfaces were almost same. The constants for fatty acids and fatty acid esters were linearly correlated to their enthalpies of evaporation, and this correlation is expected to be useful for estimating the Henry's constants for other fatty acids and their esters.


Subject(s)
Lipids/chemistry , Oxygen/chemistry , Water/chemistry , Esters/chemistry , Fatty Acids/chemistry , Laurates/chemistry , Lipid Peroxidation , Rapeseed Oil/chemistry , Solubility , Thermodynamics , Triglycerides/chemistry
19.
Carbohydr Polym ; 256: 117525, 2021 Mar 15.
Article in English | MEDLINE | ID: mdl-33483046

ABSTRACT

Microfibrillated cellulose (MFC) is widely used as a reinforcement filler for biocomposites due to its unique properties. However, the challenge of drying MFC and the incompatibility between nanocellulose and polymer matrix still limits the mechanical performance of MFC-reinforced biocomposites. In this study, we used a water-based transesterification reaction to functionalize MFC and explored the capability of oven-dried MFC as a reinforcement filler for polylactic acid (PLA). Remarkably, this oven-dried, vinyl laurate-modified MFC improved the tensile strength by 38 % and Young's modulus by 71 % compared with neat PLA. Our results suggested improved compatibility and dispersion of the fibrils in PLA after modification. This study demonstrated that scalable water-based surface modification and subsequent straightforward oven drying could be a facile method for effectively drying cellulose nanomaterials. The method helps significantly disperse fibrils in polymers and enhances the mechanical properties of microfibrillar cellulose-reinforced biocomposites.


Subject(s)
Cellulose/chemistry , Laurates/chemistry , Nanocomposites/chemistry , Polyesters/chemistry , Vinyl Compounds/chemistry , Calorimetry, Differential Scanning , Cellulose/ultrastructure , Desiccation/methods , Elastic Modulus , Humans , Materials Testing , Microscopy, Electron, Scanning , Nanocomposites/ultrastructure , Surface Properties , Tensile Strength , Thermogravimetry , Water/chemistry
20.
Carbohydr Polym ; 256: 117560, 2021 Mar 15.
Article in English | MEDLINE | ID: mdl-33483062

ABSTRACT

The recent progress in the manufacturing of new functional cellulose-derived materials shows that the renewable side of these materials does not ensure sustainable development. In contrast, reaction/process design and waste minimization play a key role here. Herein, reactive extrusion was used as a fast method for cellulose transesterification with vinyl laurate in 1-ethyl-3-methylimidazolium acetate (EmimOAc)/DMSO system. It was demonstrated that cellulose laurate can be synthesized with high reaction efficiency (91 %). The low amount of solvent during the process provides high cellulose concentration (20 wt%) mild chemical modification within minutes and without any depolymerization. Temperature has a significant influence on the reaction kinetics. To examine the sustainability of the process E-factor was employed. Processing properties of obtained cellulose laurates were investigated. Samples with DS of 2.5 and higher can be easily extruded showing low melt viscosity. EmimOAc was recovered and reused for subsequent cellulose transesterification exhibiting high catalytic activity.


Subject(s)
Cellulose/chemistry , Imidazoles/chemistry , Ionic Liquids/chemistry , Laurates/chemistry , Solvents/chemistry , Calorimetry, Differential Scanning , Catalysis , Esterification , Kinetics , Magnetic Resonance Spectroscopy , Reference Values , Solubility , Spectroscopy, Fourier Transform Infrared , Temperature , Thermogravimetry , Viscosity , X-Ray Diffraction
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