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Structural formula of phosphatidylcholine molecule and its derivatives/related phospholipids. The chemical moieties on the right panel replace the Choline moiety depicted on the left panel, and hence each phospholipid molecule is named based on its specific moiety on its hydrophilic head group.
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Introduction: Bioactive encapsulation and drug delivery systems have already found their way to the market as efficient therapeutics to combat infections, viral diseases and different types of cancer. The fields of food fortification, nutraceutical supplementation and cosmeceuticals have also been getting the benefit of encapsulation technologies....
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Context 1
... known as a bilayer phospholipid vesicle, liposome is a mesomorphic structure mainly composed of lipid, phospholipid and water molecules [32]. The main chemical components of liposomes and nanoliposomes are amphiphilic lipid/phospholipid molecules (Figure 1). They improve the efficacy of pharmaceutical, nutraceutical and other bioactive compounds by entrapment and release of water-soluble, lipid-soluble and amphipathic materials, as well as targeting the encapsulated drug molecules to particular cells or tissues [33,34]. ...
Context 2
... the surface area of vesicle's monolayer; d is the diameter of the vesicle; h is the thickness of the phospholipid bilayer (i.e., ~5 nm); a is the phospholipid head group area and E2 is exponent two (to the power 2). The headgroup area of phosphatidylcholine (a generally used ingredient in the manufacture of lipid vesicles, niosomes, tocosomes, etc.) is about 0.71 nm square, as depicted in Figure 1 [35][36][37]. Accordingly, Equation (4) can be simplified to: ...
Context 3
... known as a bilayer phospholipid vesicle, liposome is a mesomorphic structure mainly composed of lipid, phospholipid and water molecules [32]. The main chemical components of liposomes and nanoliposomes are amphiphilic lipid/phospholipid molecules (Figure 1). They improve the efficacy of pharmaceutical, nutraceutical and other bioactive compounds by entrapment and release of water-soluble, lipid-soluble and amphipathic materials, as well as targeting the encapsulated drug molecules to particular cells or tissues [33,34]. ...
Context 4
... the surface area of vesicle's monolayer; d is the diameter of the vesicle; h is the thickness of the phospholipid bilayer (i.e., ~5 nm); a is the phospholipid head group area and E2 is exponent two (to the power 2). The headgroup area of phosphatidylcholine (a generally used ingredient in the manufacture of lipid vesicles, niosomes, tocosomes, etc.) is about 0.71 nm square, as depicted in Figure 1 [35][36][37]. Accordingly, Equation (4) can be simplified to: ...
Citations
... The R S of 4.3 nm for LDH was taken from (Zinkham et al., 1968). To relate the surface occupancy to the ratio between protein in solution and amount of lipids used for liposome preparation, we took into account the total number of lipids per spherical unilamellar liposome (n l/tot ) with n l,tot ¼ P f là 4Ãπà R S,lipo ð Þ 2 þ4Ãπà R S,lipo Àd ð Þ 2  à a , (Mozafari et al., 2021), where (f l ) is the fraction of each respective lipid species in the liposome mixture, R S,lipo the R S of the liposome (nm), d the bilayer thickness (nm), and (a) the lipid head group area for the respective lipid (nm 2 ), both taken from (Navarro-Retamal et al., 2018) for monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), and sulfoquinovosyldiacylglycerol (SQDG) and from (Shahane et al., 2019) for egg Lα-phosphatidylglycerol (EPG). Thus, the surface occupancy can be expressed as c Prot Ãa Prot Ãn l,tot ÃMW Lipid a target Ãc Lipid ÃMW Prot for liposomes and c Prot Ãa Prot ÃMW LDH a target Ãc LDH ÃMW Prot for LDH, where c Prot , c LDH , and c Lipid are the concentrations (mg/mL) and MW Prot , MW LDH , and MW Lipid are the molecular mass (g/mol) of the protectant and the targets, respectively. ...
Intrinsically disordered late embryogenesis abundant (LEA) proteins play a central role in the tolerance of plants and other organisms to dehydration brought upon, for example, by freezing temperatures, high salt concentration, drought or desiccation, and many LEA proteins have been found to stabilize dehydration‐sensitive cellular structures. Their conformational ensembles are highly sensitive to the environment, allowing them to undergo conformational changes and adopt ordered secondary and quaternary structures and to participate in formation of membraneless organelles. In an interdisciplinary approach, we discovered how the functional diversity of the Arabidopsis thaliana LEA protein COR15A found in vitro is encoded in its structural repertoire, with the stabilization of membranes being achieved at the level of secondary structure and the stabilization of enzymes accomplished by the formation of oligomeric complexes. We provide molecular details on intra‐ and inter‐monomeric helix–helix interactions, demonstrate how oligomerization is driven by an α‐helical molecular recognition feature (α‐MoRF) and provide a rationale that the formation of noncanonical, loosely packed, right‐handed coiled‐coils might be a recurring theme for homo‐ and hetero‐oligomerization of LEA proteins.
... Second, after rehydration in PBS, liposomes were extruded at a temperature above 60° C (the T m of DSPC), with 30 passes through a 100 nm membrane with an Avanti Polar Lipids Extruder. The concentration of lipids was calculated according to established methods (Mozafari et al., 2021). ...
Initial studies on the immunogenicity of SARS-CoV-2 (CoV-2) spike protein as a protein subunit vaccine suggested sub-optimal efficacy in mammals. Although protein engineering efforts have produced CoV-2 spike protein sequences with greatly improved immunogenicity, additional strategies for improving the immunogenicity of CoV-2 protein subunit vaccines are scaffolding and the use of adjuvants. Comparisons of the effectiveness of engineered protein-only and engineered protein-nanoparticles vaccines have been rare. To address this gap, we inoculated mice with two doses of either sequence-optimized trimeric spike protein or one of several sequence-optimized spike nanoparticles. We measured their immune response up to two months after the first dose. We also measured the immune response and protection against live virus in hamsters inoculated with either sequence-optimized trimeric spike protein or a liposome-based sequence-optimized spike nanoparticle. We found that in the presence of adjuvant, the antibody and neutralization titers elicited by spike-nanoparticles were not significantly greater than those elicited by spike-only in mice, even at doses as low as 0.1 µg/animal. Hamsters vaccinated with spike-only or spike-nanoparticles were equally protected from live virus one month after their first inoculation. These results indicate that sequence-optimized protein subunit vaccines in the form of individual prefusion-stabilized trimers can be as effective in improving immunogenicity as in scaffolded form.
... Thus, precise determination and control of concentration are key characteristics of NDDSs in nanomedicine to achieve maximum of drug efficacy and to minimize their toxicity in vivo [8]. There are theoretical methods for calculating the concentration of NPs [9,10]. Although mathematical models are quite simple, there are limitations for calculations, as well as discrepancies between theoretical value and empirical results [11]. ...
... Thus, precise determination and control of concentration are key characteristics of NDDSs in nanomedicine to achieve maximum of drug efficacy and to minimize their toxicity in vivo [8]. There are theoretical methods for calculating the concentration of NPs [9,10]. Although mathematical models are quite simple, there are limitations for calculations, as well as discrepancies between theoretical value and empirical results [11]. ...
Currently, there are problems to standardize methods for determining the concentration of nanoparticles and creation of etalon materials for calibrating measured concentrations. Accurate determination of nanoparticle concentration is necessary to assess the maximum dose of administered nanotherapeutics for diagnostics and therapy in vivo, to determine the order of reaction in enzymatic nanoreactors. In addition, this parameter determines biological effects, such as the formation of a protein corona on the outer surface of nanoparticles that precedes nanoparticles’ absorption and internalization in cells. This review discusses the most common methods for determining the concentration of nanoparticles based on direct visualization, using microscopy, light absorption or light scattering, direct counting of nanoparticles, and gravimetry. Results may differ from one method to the other. Thus, the use of a combination of several methods provides more reliable results. The advantages, disadvantages and ways to improve accuracy of results are also presented.
... Due to the highest LC, F1 was chosen as the suitable formulation to characterize the physicochemical structure further. The particle number of F1 was calculated according to the previous study [26]. The number of particles was 6.5 × 10 11 vesicles/mL corresponding to 3.52 ± 0.01 mg/mL of EEP. ...
Secretory phospholipase B1 (PLB1) and biofilms act as microbial virulence factors and play an important role in pulmonary cryptococcosis. This study aims to formulate the ethanolic extract of propolis-loaded niosomes (Nio-EEP) and evaluate the biological activities occurring during PLB1 production and biofilm formation of Cryptococcus neoformans. Some physicochemical characterizations of niosomes include a mean diameter of 270 nm in a spherical shape, a zeta-potential of −10.54 ± 1.37 mV, and 88.13 ± 0.01% entrapment efficiency. Nio-EEP can release EEP in a sustained manner and retains consistent physicochemical properties for a month. Nio-EEP has the capability to permeate the cellular membranes of C. neoformans, causing a significant decrease in the mRNA expression level of PLB1. Interestingly, biofilm formation, biofilm thickness, and the expression level of biofilm-related genes (UGD1 and UXS1) were also significantly reduced. Pre-treating with Nio-EEP prior to yeast infection reduced the intracellular replication of C. neoformans in alveolar macrophages by 47%. In conclusion, Nio-EEP mediates as an anti-virulence agent to inhibit PLB1 and biofilm production for preventing fungal colonization on lung epithelial cells and also decreases the intracellular replication of phagocytosed cryptococci. This nano-based EEP delivery might be a potential therapeutic strategy in the prophylaxis and treatment of pulmonary cryptococcosis in the future.
... Due to the highest LC, F1 was chosen as the suitable formulation to characterize the physicochemical structure further. The particle number of F1 was calculated according to the previous study [26]. The number of particles was 6.5 × 10 11 vesicles/mL corresponding to 3.52 ± 0.01 mg/mL of EEP. ...
Secretory phospholipase B1 (PLB1) and biofilms act as microbial virulence factors and play an important role in pulmonary cryptococcosis. This study aims to formulate the ethanolic extract of propolis-loaded niosomes (Nio-EEP) and evaluate the biological activities occurring during PLB1 production and biofilm formation of Cryptococcus neoformans. Some physicochemical characterizations of niosomes include a mean diameter of 270 nm in a spherical shape, a zeta-potential of −10.54 ± 1.37 mV, and 88.13 ± 0.01% entrapment efficiency. Nio-EEP can release EEP in a sustained manner and retains consistent physicochemical properties for a month. Nio-EEP has the capability to permeate the cellular membranes of C. neoformans, causing a significant decrease in the mRNA expression level of PLB1. Interestingly, biofilm formation, biofilm thickness, and the expression level of biofilm-related genes (UGD1 and UXS1) were also significantly reduced. Pre-treating with Nio-EEP prior to yeast infection reduced the intracellular replication of C. neoformans in alveolar macrophages by 47%. In conclusion, Nio-EEP mediates as an anti-virulence agent to inhibit PLB1 and biofilm production for preventing fungal colonization on lung epithelial cells and also decreases the intracellular replication of phagocytosed cryptococci. This nano-based EEP delivery might be a potential therapeutic strategy in the prophylaxis and treatment of pulmonary cryptococcosis in the future.
... As the model of biomembranes (i.e., plasma membrane), artificial membranes comprising of lipids and proteins have been extensively used in biophysical research to understand the processes of living organisms because of their simpler structures and known physical properties [4,5]. Among the artificial vesicles, giant unilamellar vesicles (GUVs) can be used for the investigations of interaction of nanoparticles (NPs) with membranes containing PEG-grafted phospholipid using optical microscopes because the size-range of GUVs is comparable to that of biological cells [6][7][8]. ...
The hydrophilic polymer polyethylene glycol-grafted phospholipid has been used extensively in the study of artificial vesicles, nanomedicine, and antimicrobial peptides/proteins. In this research, the effects of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N- [methoxy (polyethylene glycol)-2000] (abbreviated PEG-DOPE) on the deformation and poration of giant unilamellar vesicles (GUVs)-induced by anionic magnetite nanoparticles (NPs) have been investigated. For this, the size of the NPs used was 18 nm, and their concentration in the physiological solution was 2.00 μg/mL. GUVs were prepared using the natural swelling method comprising 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and PEG-DOPE. The mole% of PEG-DOPE in the membranes were 0, 2, and 5%. The degree of deformation of the GUVs was quantified by the parameter compactness (Com), which is 1.0 for the spherical-shaped GUVs. The value of Com increases with time during the interactions of NPs with GUVs for any concentration of PEG-DOPE, but the rate of increase is significantly influenced by the PEG-DOPE concentration in the membranes. The average compactness increases with the increase of PEG-DOPE%, and after 60 min of NPs interaction, the values of average compactness for 0, 2, and 5% PEG-DOPE were 1.19 ± 0.02, 1.26 ± 0.03 and 1.35 ± 0.05, respectively. The fraction of deformation (Frd) also increased with the increase of PEG-DOPE%, and at 60 min, the values of Frd for 0 and 5% PEG-DOPE were 0.47 ± 0.02 and 0.63 ± 0.02, respectively. The fraction of poration (Frp) increased with the increase of PEG-DOPE, and at 60 min, the values of Frp for 0 and 5% PEG-DOPE were 0.25 ± 0.02 and 0.48 ± 0.02, respectively. Hence, the presence of PEG-grafted phospholipid in the membranes greatly enhances the anionic magnetite NPs-induced deformation and poration of giant vesicles.
... Transfersome suspension was characterized in terms of MHD, PDI, and ζ-potential by dynamic light scattering (DLS, mod. Zetasizer Nano S, Worcestershire, United Kingdom) [21]. All measurements were performed in triplicate. ...
Transfersomes are deformable vesicles that can transport drugs across difficult-to-permeate barriers in human tissues. In this work, nano-transfersomes were produced for the first time by a supercritical CO2 assisted process. Operating at 100 bar and 40 °C, different amounts of phosphatidylcholine (2000 and 3000 mg), kinds of edge activators (Span® 80 and Tween® 80), and phosphatidylcholine to edge activator weight ratio (95:5, 90:10, 80:20) were tested. Formulations prepared using Span® 80 and phosphatidylcholine at an 80:20 weight ratio produced stable transfersomes (−30.4 ± 2.4 mV ζ-potential) that were characterized by a mean diameter of 138 ± 55 nm. A prolonged ascorbic acid release of up to 5 h was recorded when the largest amount of phosphatidylcholine (3000 mg) was used. Moreover, a 96% ascorbic acid encapsulation efficiency and a quasi-100% DPPH radical scavenging activity of transfersomes were measured after supercritical processing.
... After exposure to BDPA-CMs, fluorescence intensities of negatively charged liposomal dispersions dropped approximately 21% for BDPA-CM-I, 11% for BDPA-CM-II, and 20% for BDPA-CM-III with respect to their controls. This corresponds to binding of negatively charged liposomes at approximately 0.11 μmol/ (Mozafari et al. 2021). Assuming a particle diameter of 62 μm for BDPA-CMs and a cellulose density of 1.5 g/cm 3 , binding capacity of BDPA-CM-I for negatively charged liposomes would be 3.78 × 10 8 liposomes/mg and approximately 69,000 liposomes per single BDPA derivatized cellulose microsphere. ...
Spherical materials capable of binding to negatively charged biomembrane bearing species like bacterial cells in still or flowing liquids can have a number of important applications. For example, they could be used to remove bacterial cells from blood facilitating the diagnosis and treatment of bacteremia (i.e., bacterial infection of blood). Other applications involve removal of such species from aqueous foodstuffs, pharmaceutical formulations, and wastewater discharges. Here we report of the preparation of bis(dipicolylamine) (BDPA) bearing nonporous cellulose microspheres (CMs) for the sequestration of negatively charged biomembrane bearing species. When complexed with Zn²⁺ ions, BDPA ligands are capable of binding to biomembranes that display negatively charged phosphate amphiphiles on their outer surfaces. Three different chemical ligation strategies (amide bond formation, reductive amination, and epoxide opening) were employed to obtain BDPA derivatized CMs. Using fluorescence microscopy and spectroscopy it was demonstrated that these BDPA-CMs were capable of binding to negatively charged liposomes, but not to neutral liposomes. Fluorescence microscopy also revealed that all the BDPA-CMs were capable of binding to green fluorescent protein-expressing Escherichia coli (K12). Quantification of bacterial binding of one of these BDPA-CMs revealed binding capacities of 1.01 × 10⁸ colony forming units (CFU)/g for E. coli (K12) through fluorescence spectroscopy, and ≥ 8.96 × 10⁷ and 5.93 × 10⁷ CFU/g respectively for E. coli (ATCC 35049) and Staphylococcus aureus (ATCC 25923) using optical density measurements at 600 nm (OD600). Such high binding capacities make these materials good candidates for future applications where sequestration of bacterial cells and other species with similar membrane properties from liquids is desired.
Graphical abstract
... In order to calculate the number of phospholipid vesicles, in the form of a unilamellar vesicle, in any particular volume of sample, Eq. 3 was used. Once the total concentration of phospholipids of our liposomes in the suspending media is known, then the total number of particles per mL can be calculated (Mozafari et al. 2021). ...
... where N lipo is the number of liposomes per milliliter; M lipid is the molar concentration of lipid; NA is the Avogadro Number (6.02 × 10 23 ), and N tot is the total number of lipids per liposome which can be calculated using the following equation (Eq. 4) (Mozafari et al. 2021): where R is the radius of vesicles, h is the thickness of the phospholipid bilayer (i.e., ∼ 5 nm) (Mozafari et al. 2021;Regan et al. 2019), and a is the phospholipid head group area (for the DOPC, headgroup is 0.725 nm 2 ) (Petrache et al. 2004). For this equation, the size of control liposomes measured by zeta sizer was used. ...
... where N lipo is the number of liposomes per milliliter; M lipid is the molar concentration of lipid; NA is the Avogadro Number (6.02 × 10 23 ), and N tot is the total number of lipids per liposome which can be calculated using the following equation (Eq. 4) (Mozafari et al. 2021): where R is the radius of vesicles, h is the thickness of the phospholipid bilayer (i.e., ∼ 5 nm) (Mozafari et al. 2021;Regan et al. 2019), and a is the phospholipid head group area (for the DOPC, headgroup is 0.725 nm 2 ) (Petrache et al. 2004). For this equation, the size of control liposomes measured by zeta sizer was used. ...
nirC gene coding for the nitrite channel of E. coli K12 was cloned into the pET28a vector and expressed in E. coli BL21 cells. 28.5 kDa NirC monomer was purified from membrane components of E. coli. Selectivity of NirC for different ions including nitrite, nitrate, sulfate, formate, and acetate anions, and a divalent cation, magnesium, was compared with that of bacterial aquaporin from Halomonas elongata. Water and ion permeability values were determined by measuring the light scattering rates of proteoliposomes containing NirC and aquaporins during their water loss and gain. NirC shows a selective permeability to nitrite and is more resistant to the entry of other anions as compared to aquaporin. The single channel permeability of NirC for nitrite is about 10-fold that of a single aquaporin channel. Both aquaporin and NirC channel proteins were impermeable to MgCl2 and (NH4)2SO4 and their permeability to other tested ions was remarkably lower as compared to nitrite ions. The study also presents the 3D model and channel characteristics of NirC. The translocation channel of E. coli NirC is determined to be larger, and its length is shorter than aquaporin channels. Although the NirC channel throat is more hydrophobic than aquaporin, its water permeability is almost equal to that of aquaporin. The hydrophobic nature of the NirC channel might play an important role in the selective permeability of the channel for nitrite ions.
