Stability Of Vesicles Research Articles

Exploring lipids: A comprehensive review on their utilization in the formulation of liposomes, phytosomes, and ethosomes for advanced drug delivery systems"

This comprehensive review explores the diverse applications of lipids in the formulation of advanced drug delivery systems, specifically focusing on liposomes, phytosomes, and ethosomes. Lipids, crucial components in these formulations, play a pivotal role in enhancing drug solubility, stability, and bioavailability. The review systematically examines the latest advancements in lipid-based delivery systems, shedding light on their unique characteristics and applications. In the realm of liposomes, the study delves into various lipid compositions, highlighting their influence on liposomal structure and function. Additionally, the review explores the integration of phytosomes, which involve the complexation of drugs with plant-derived phospholipids, showcasing their potential to improve therapeutic efficacy. Ethosomes, lipid vesicles containing high concentrations of ethanol, are also extensively discussed, emphasizing their ability to enhance transdermal drug delivery. Critical analyses of recent research findings, including the impact of lipid selection on vesicle stability, drug release kinetics, and pharmacokinetics, are presented. The review further examines the challenges associated with lipid-based formulations, providing insights into potential avenues for future research and development. By synthesizing current knowledge, this review serves as a valuable resource for researchers, clinicians, and pharmaceutical scientists seeking a comprehensive understanding of the role of lipids in optimizing liposomal, phytosomal, and ethosomal drug delivery systems.

Enhanced assembly stability for amine-based cationic glycolipid

Glycolipids incorporating positive charges, mediated by an imidazolium cation, have shown potential for effective formulation of vesicular drug carriers, reflecting repulsive electrostatic forces, promoting the formation of nanosized assemblies and preventing unwanted Oswald ripening (Goh et al. (2019), ACS Omega 4, 17,039). Our continuous development of an assembly-based drug delivery system prompted us to investigate a pH-sensitive analogue, leading to the synthesis of a 6-amino-Guerbet glycoside. However, in contrast to the imidazolium counterpart, the amine-mediated charge increased the intermolecular cohesions, furnishing bigger assemblies instead, which further increased upon introduction of acid. Moreover, assemblies exhibited a significantly reduced positive charge density. It is concluded that strong proton-initiated hydrogen bonding between amino groups provide cohesive head group interactions overcompensating possible repulsive charge interactions. While this behavior invalidates the application of the amino-glucoside as dispersing agent for the formulation of small vesicles, it potentially paves a route towards enhanced vesicle stability.

Physicochemical Studies on Amino Acid Based Metallosurfactants in Combination with Phospholipid.

Dicarboxylate metallosurfactants (AASM), synthesized by mixing N-dodecyl aminomalonate, -aspartate and -glutamate with CaCl2, MnCl2 and CdCl2, were characterized by XRD, FTIR, and NMR spectroscopy. Layered structures, formed by metallosurfactants, were evidenced from differential scanning calorimetry and thermogravimetric analyses. Solvent-spread monolayer of AASM in combination with soyphosphatidylcholine (SPC) and cholesterol (CHOL) were studied using Langmuir surface balance. With increasing mole fraction of AASM mean molecular area increased and passed through maxima at ~60 mol% of AASMs, indicating molecular packing reorganization. Systems with 20 and 60 mol% AASM exhibited positive deviations from ideal behavior signifying repulsive interaction between the AASM and SPC, while synergistic interactions were established from the negative deviation at other combinations. Dynamic surface elasticity increased with increasing surface pressure signifying formation of rigid monolayer. Transition of monolayer from gaseous to liquid expanded to liquid condensed state was established by Brewster angle microscopic studies. Stability of the hybrid vesicles, formed by AASM+SPC+CHOL, were established by monitoring their size, zeta potential and polydispersity index values over 100 days. Size and spherical morphology of hybrid vesicles were confirmed by transmission electron microscopic studies. Biocompatibility of the hybrid vesicles were established by cytotoxicity studies revealing their possible applications in drug delivery and imaging.

Microfluidic production, stability and loading of synthetic giant unilamellar vesicles

In advanced drug delivery, versatile liposomal formulations are commonly employed for safer and more accurate therapies. Here we report a method that allows a straightforward production of synthetic monodisperse (~ 100 μm) giant unilamellar vesicles (GUVs) using a microfluidic system. The stability analysis based on the microscopy imaging showed that at ambient conditions the produced GUVs had a half-life of 61 ± 2 h. However, it was observed that ~ 90% of the calcein dye that was loaded into GUVs was transported into a surrounding medium in 24 h, thus indicating that the GUVs may release these small dye molecules without distinguishable membrane disruption. We further demonstrated the feasibility of our method by loading GUVs with larger and very different cargo objects; small soluble fluorescent proteins and larger magnetic microparticles in a suspension. Compared to previously reported microfluidics-based production techniques, the obtained results indicate that our simplified method could be equally harnessed in creating GUVs with less cost, effort and time, which could further benefit studying closed membrane systems.

Polysaccharide functionalization reduces lipid vesicle stiffness

The biophysical properties of lipid vesicles are important for their stability and integrity, key parameters that control the performance when these vesicles are used for drug delivery. The vesicle properties are determined by the composition of lipids used to form the vesicle. However, for a given lipid composition, they can also be tailored by tethering polymers to the membrane. Typically, synthetic polymers like polyethyleneglycol are used to increase vesicle stability, but the use of polysaccharides in this context is much less explored. Here, we report a general method for functionalizing lipid vesicles with polysaccharides by binding them to cholesterol. We incorporate the polysaccharides on the outer membrane leaflet of giant unilamellar vesicles (GUVs) and investigate their effect on membrane mechanics using micropipette aspiration. We find that the presence of the glycolipid functionalization produces an unexpected softening of GUVs with fluid-like membranes. By contrast, the functionalization of GUVs with polyethylene glycol does not reduce their stretching modulus. This work provides the potential means to study membrane-bound meshworks of polysaccharides similar to the cellular glycocalyx; moreover, it can be used for tuning the mechanical properties of drug delivery vehicles.

Superior Drug Delivery Performance of Multifunctional Bilosomes: Innovative Strategy to Kill Skin Cancer Cells for Nanomedicine Application.

Numerous failures in melanoma treatment as a highly aggressive form of skin cancer with an unfavorable prognosis and excessive resistance to conventional therapies are prompting an urgent search for more effective therapeutic tools. Consequently, to increase the treatment efficiency and to reduce the side effects of traditional administration ways, herein, it has become crucial to combine photodynamic therapy as a promising therapeutic approach with the selectivity and biocompatibility of a novel colloidal transdermal nanoplatform for effective delivery of hybrid cargo with synergistic effects on melanoma cells. The self-assembled bilosomes, co-stabilized with L-α-phosphatidylcholine, sodium cholate, Pluronic® P123, and cholesterol, were designated, and the stability of colloidal vesicles was studied using dynamic and electrophoretic light scattering, also provided in cell culture medium (Dulbecco's Modified Eagle's Medium). The hybrid compounds - a classical photosensitizer (Methylene Blue) along with a complementary natural polyphenolic agent (curcumin), were successfully co-loaded, as confirmed by UV-Vis, ATR-FTIR, and fluorescent spectroscopies. The biocompatibility and usefulness of the polymer functionalized bilosome with loaded double cargo were demonstrated in vitro cyto- and phototoxicity experiments using normal keratinocytes and melanoma cancer cells. Thein vitrobioimaging and immunofluorescence study upon human skin epithelial (A375) and malignant (Me45) melanoma cell lines established the protective effect of the PEGylated bilosome surface. This effect was confirmed in cytotoxicity experiments, also determined on human cutaneous (HaCaT) keratinocytes. The flow cytometry experiments indicated the enhanced uptake of the encapsulated hybrid cargo compared to the non-loaded MB and CUR molecules, as well as a selectivity of the obtained nanocarriers upon tumor cell lines. The phyto-photodynamic action provided 24h-post irradiation revealed a more significant influence of the nanoplatform on Me45 cells in contrast to the A375 cell line, causing the cell viability rate below 20% of the control. As a result, we established an innovative and effective strategy for potential metastatic melanoma treatment through the synergism of phyto-photodynamic therapy and novel bilosomal-origin nanophotosensitizers.

Effect of In Vitro Enzyme Digestion and Bile Treatment on Milk Extracellular Vesicles Stability.

Milk extracellular vesicles (EVs) are nanosized particles with potential immune bioactivities. This study examines their fate during in vitro infant gastrointestinal digestion (GI). Bovine milk is digested using the in vitro INFOGEST method, adjusted for the infant. To unravel the contribution of digestive enzymes from bile, milk is treated with digestive enzymes, bile, or a combination of both. EVs are collected posttreatment using differential ultracentrifugation. EVs characterization includes electrophoresis, immunoblotting, nanoparticle tracking analysis, and atomic force microscopy. EVs protein markers programmed cell death 6-interacting protein (ALIX), tumor susceptibility gene 101 (TSG101), cluster of differentiation 9 (CD9), and xanthine dehydrogenase (XDH) are detected after gastric digestion (G60), but their signal intensity is significantly reduced by intestinal conditions (p<0.05). Enzyme digestion, compared to bile treatment (I60+bile), results in a significant reduction of signal intensities for TSG101 and CD9 (p<0.05). Nanoparticle tracking analysis shows a significant reduction (p<0.05) of EV numbers at the end of the intestinal phase. EVs are detected by atomic force microscopy at the end of the intestinal phase, showing that intact EVs can survive upper gut digestion. Intact EVs can be found at the end of the intestinal phase. However, digestive enzymes and bile reduce the quantity and characteristics of EVs, with digestive enzymes playing a larger role.

Flow-driven translocation of polymer vesicle through a nanochannel

Flow-driven translocation of a polymer vesicle self-assembled from amphiphilic diblock copolymers through a nanochannel is studied using hybrid Lattice-Boltzmann Molecular Dynamics simulations. Three translocation modes are discovered: a single vesicle, small vesicles, and tiny micelles in sequence, respectively, as the width of the nanochannel is decreased, which is confirmed by the self-consistent field theory calculations. Accordingly, spherical vesicles, ellipsoidal vesicles, and worm-like micelles are formed sequentially after crossing the nanochannel. More importantly, we find that the critical flow rate monotonically decreases as the ratio of the polymer vesicle size and the width of the nanochannel decreases until it approaches 1. Our results provide a basis for characterizing the stability of vesicles or sorting vesicles with different sizes and also point to a new idea of regulating spherical vesicles to ellipsoidal vesicles or worm-like micelles.

Stabilization of Prebiotic Vesicles by Peptides Depends on Sequence and Chirality: A Mechanism for Selection of Protocell-Associated Peptides.

Cells require oligonucleotides and polypeptides with specific, homochiral sequences to perform essential functions, but it is unclear how such oligomers were selected from random sequences at the origin of life. Cells were probably preceded by simple compartments such as fatty acid vesicles, and oligomers that increased the stability, growth, or division of vesicles could have thereby increased in frequency. We therefore tested whether prebiotic peptides alter the stability or growth of vesicles composed of a prebiotic fatty acid. We find that three of 15 dipeptides tested reduce salt-induced flocculation of vesicles. All three contain leucine, and increasing their length increases the efficacy. Also, leucine-leucine but not alanine-alanine increases the size of vesicles grown by multiple additions of micelles. In a molecular simulation, leucine-leucine docks to the membrane, with the side chains inserted into the hydrophobic core of the bilayer, while alanine-alanine fails to dock. Finally, the heterochiral forms of leucine-leucine, at a high concentration, rapidly shrink the vesicles and make them leakier and less stable to high pH than the homochiral forms do. Thus, prebiotic peptide-membrane interactions influence the flocculation, growth, size, leakiness, and pH stability of prebiotic vesicles, with differential effects due to sequence, length, and chirality. These differences could lead to a population of vesicles enriched for peptides with beneficial sequence and chirality, beginning selection for the functional oligomers that underpin life.

Daptomycin Liposomes Exhibit Enhanced Activity against Staphylococci Biofilms Compared to Free Drug.

The purpose of the present study was to investigate the anti-staphylococcal activity of liposomal daptomycin against four biofilm-producing S. aureus and S. epidermidis clinical strains, three of which are methicillin-resistant. Neutral and negatively charged daptomycin-loaded liposomes were prepared using three methods, namely, thin-film hydration (TFH), a dehydration-rehydration vesicle (DRV) method, and microfluidic mixing (MM); moreover, they were characterized for drug encapsulation (EE%), size distribution, zeta-potential, vesicle stability, drug release, and drug integrity. Interestingly, whilst drug loading in THF and DRV nanosized (by extrusion) vesicles was around 30-35, very low loading (~4%) was possible in MM vesicles, requiring further explanatory investigations. Liposomal encapsulation protected daptomycin from degradation and preserved its bioactivity. Biofilm mass (crystal violet, CV), biofilm viability (MTT), and growth curve (GC) assays evaluated the antimicrobial activity of neutral and negatively charged daptomycin-liposomes towards planktonic bacteria and biofilms. Neutral liposomes exhibited dramatically enhanced inhibition of bacterial growth (compared to the free drug) for all species studied, while negatively charged liposomes were totally inactive. Biofilm prevention and treatment studies revealed high antibiofilm activity of liposomal daptomycin. Neutral liposomes were more active for prevention and negative charge ones for treating established biofilms. Planktonic bacteria as well as the matured biofilms of low daptomycin-susceptible, methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE) strains were almost completely eradicated by liposomal-daptomycin, indicating the need for their further exploration as antimicrobial therapeutics.

Bilayer Charge Asymmetry and Oil Residues Destabilize Membranes upon Poration.

Transmembrane asymmetry is ubiquitous in cells, particularly with respect to lipids, where charged lipids are mainly restricted to one monolayer. We investigate the influence of anionic lipid asymmetry on the stability of giant unilamellar vesicles (GUVs), minimal plasma membrane models. To quantify asymmetry, we apply the fluorescence quenching assay, which is often difficult to reproduce, and caution in handling the quencher is generally underestimated. We first optimize this assay and then apply it to GUVs prepared with the inverted emulsion transfer protocol by using increasing fractions of anionic lipids restricted to one leaflet. This protocol is found to produce highly asymmetric bilayers but with ∼20% interleaflet mixing. To probe the stability of asymmetric versus symmetric membranes, we expose the GUVs to porating electric pulses and monitor the fraction of destabilized vesicles. The pulses open macropores, and the GUVs either completely recover or exhibit leakage or bursting/collapse. Residual oil destabilizes porated membranes, and destabilization is even more pronounced in asymmetrically charged membranes. This is corroborated by the measured pore edge tension, which is also found to decrease with increasing charge asymmetry. Using GUVs with imposed transmembrane pH asymmetry, we confirm that poration-triggered destabilization does not depend on the approach used to generate membrane asymmetry.

Sugar-based Cryoprotectants Stabilize Liposomal Vesicles by Exhibiting a Cholesterol-like Effect.

Liposomal vesicles tend to fuse and aggregate during lyophilization. To avoid these events, cryoprotectants are added to the dispersion before lyophilization. Herein, we have compared the effect of three commonly used cryoprotectants (mannitol, MTL; trehalose, THL; and β-cyclodextrin, β-CD) upon structural characteristics of liposomes. The formulation was prepared using ethanol injection method, and cryoprotectants were tested at three dose levels (2, 6, and 10 mM). We have elucidated their effect on soy lecithin (SL) liposomes formulated with and without cholesterol (CHL). Characterizations were performed using scattering, thermal, and spectroscopic techniques. CHL molecules interacted hydrophobically with the SL bilayer. In spite of triggering a noticeable increase in the hydrodynamic diameter (about 30 nm), CHL promoted the stabilization of vesicles. Hydrogen bonding interactions were verified by the shift in -OH stretching over 3300-3500 cm-1. This manifested in an increased phase transition temperature (Tm) of SL liposomes. Tm increased further upon incorporation of cryoprotectants, particularly with β-CD. Enthalpic changes were indicative of an affinity interaction between phospholipids and cryoprotectants, regardless of the presence of CHL. β-CD showed concentration-dependent changes in the energetics of this interaction. The affinity of cryoprotectant-liposome interaction has been ranked as β-CD ≫ THL > MNT.

Fabrication of Microalgae Oil Vesicles for Drug Delivery Applications.

In this study, it is demonstrated that natural microalgae oils, which contain fatty acid components including docosahexaenoic acid (DHA), could be directly applied to fabricate vesicular structures in aqueous phase through a forced formation process. The microalgae oil vesicles had initial average diameters of 170- 230 nm with negative charges apparently caused by dissociation of the fatty acid components. The vesicles possessed excellent stability with lifetimes for at least 450 days. The formation of the vesicular structures with hydrophilic cores/regions was confirmed by the transmission electron microscopy (TEM) image and successful encapsulation of a hydrophilic material. For encapsulation of a hydrophobic material, lutein, the vesicle size was increased probably due to the insertion of lutein into the hydrophobic vesicular bilayer structures. The analysis of Fourier transform infrared (FTIR) spectroscopy suggested that the vesicular bilayer fluidity was decreased by encapsulating lutein. However, the lutein-encapsulating microalgae oil vesicles still possessed high stability and the vesicular structures could maintain intact even at an environmental temperature up to 60℃. Applicability of the microalgae oil vesicles as drug delivery carriers was also demonstrated by successful encapsulation of curcumin. However, when the loaded curcumin was increased to a certain amount, physical stability of the microalgae oil vesicles was significantly reduced. This is probably because the vesicular structures with only limited spaces for accommodating hydrophobic materials were strongly affected by encapsulating a large amount of curcumin. It is interesting to note that by adding egg L-α-phosphatidylcholine, the curcumin encapsulation-induced instability of the microalgae oil vesicles could be alleviated. The results indicated that vesicular structures could be fabricated from microalgae oils and the microalgae oil vesicles were capable of encapsulating hydrophilic or hydrophobic materials for drug delivery applications. The findings lay a background for further dosage form development of nutritional supplements encapsulated by natural microalgae oils.

Insight into molecular structures and dynamical properties of niosome bilayers containing melatonin molecules: a molecular dynamics simulation approach.

Niosomes represent vesicular carriers capable of encapsulating both hydrophobic and hydrophilic drugs within their inner core or bilayer shell. They are typically composed of non-ionic synthetic surfactants such as sorbitan monostearate (Span60) with the addition of cholesterol (Chol). The physical properties and stability of niosomal vesicles strongly depend on the composition of their bilayers, which plays a significant role in determining the efficiency of drug encapsulation and release in drug delivery systems. In this study, we have explored the interactions between melatonin (Mel) molecules and the niosome bilayer, as well as their resulting physical properties. Molecular dynamics simulations were employed to investigate melatonin-inserted niosome bilayers, both with and without the inclusion of cholesterol. The simulation results revealed that cholesterol notably influences the location of melatonin molecules within the niosome bilayers. In the absence of cholesterol, melatonin tends to occupy the region around the Span60 tail groups. However, in the presence of cholesterol, melatonin is found in the vicinity of the Span60 head groups. Melatonin molecules in niosome bilayers without cholesterol exhibit a more ordered orientation when compared to those in bilayers containing 50 mol% cholesterol. The bilayer structure of the Span60/Mel and Span60/Chol/Mel systems exhibited a liquid-disordered phase (Ld). In contrast, the Span60/Chol bilayer system displays a liquid-ordered phase (Lo) with less fluidity. This study reveals that melatonin induces a disorderly bilayer structure and greater lateral expansion, whereas cholesterol induces an orderly bilayer structure and a more condensed effect. Cholesterol plays a crucial role in condensing the bilayer structure with stronger interactions between Span60 and cholesterol. The addition of 50 mol% cholesterol in the Span60 bilayers not only enhances the stability and rigidity of niosomes but also facilitates the easier release of melatonin from the bilayer membranes. This finding is particularly valuable in the context of preparing niosomes for drug delivery systems.

Controlling molecular self-assembly of inverse-phosphocholine lipids at oxide interfaces with divalent cations

Sub-100 nm vesicles composed of inverse-phosphocholine (CP) lipids are versatile building blocks for interfacing with inorganic material surfaces and demonstrate unique chemical functionalities due to outward-facing phosphate groups. Compared to typical phospholipids, the surface presentation of CP lipids has enabled new covalent possibilities like click chemistry for drug delivery and imaging applications while utilizing this phosphate chemistry in noncovalent self-assembly contexts remains unexplored. Herein, we report that the presence of phosphate-binding divalent cations such as Ca2+ and Mg2+ can dramatically shift the self-assembly behavior of CP lipid vesicles on TiO2 and SiO2 surfaces, inhibiting spontaneous supported lipid bilayer (SLB) formation on TiO2 in cases where it typically occurs and promoting SLB formation on SiO2 in cases where lipid adsorption is otherwise negligible. Quartz crystal microbalance-dissipation (QCM-D) measurements were performed to track the corresponding adsorption kinetics and self-assembly outcomes. Importantly, an optimal combination of CP lipid fraction in vesicles and specific divalent cation type was also identified, which enabled SLB formation on both TiO2 and SiO2 surfaces under equivalent conditions. SLB fluidity on SiO2 surfaces was additionally confirmed by fluorescence recovery after photobleaching (FRAP) experiments. We rationalize these molecular-level phenomena in terms of vesicle stability and lipid-surface interactions, demonstrating a versatile approach to control CP lipid self-assembly with divalent cations.

Effect of invasome composition on membrane fluidity, vesicle stability and skin interactions

Invasomes have been widely exploited to enhance the percutaneous permeation of drugs. On the other hand, few studies have been dedicated to evaluating how their composition impacts the interaction with the skin, vesicle rigidity and stability, which was the focus of this investigation. Light scattering and spectroscopic techniques were considered for vesicle characterization. The addition of cholesterol (CHOL) into the phosphatidylcholine (PC) vesicles led to increased membrane rigidity (from PC:CHOL 5:0.5) and a concentration-dependent disorder effect on skin domains. Nevertheless, these vesicles were showed to be less stable. Ethanol, in turn, resulted in larger and more flexible vesicles, which can be attributed to its preferential distribution in headgroups of PC. The effect of limonene on membrane rigidity was dependent on the vesicle composition. It reduced the rigidity when few constituents were considered, but an opposite effect was observed for vesicles containing PC, CHOL, ethanol and limonene. Competitive effects of limonene and CHOL by the same domains in PC could explain these findings. Limonene was crucial to obtaining more monodisperse vesicles and it showed a synergistic action with CHOL in the disruption of lipid domains in the skin. Invasomes were more stable than liposomes. CHOL-free invasomes showed to be stable for up to 40 days at room temperature.

Stability of Blueberry Extracellular Vesicles and Their Gene Regulation Effects in Intestinal Caco-2 Cells.

Plant extracellular vesicles (P-EVs) are considered promising functional food ingredients due to their various health benefits. In this study, blueberry extracellular vesicles (B-EVs) were collected and purified by size exclusion chromatography (SEC). The chemical compounds in B-EV extracts were analyzed by LC-MS/MS. In addition, the stability of B-EVs was evaluated during short- and long-term storage, heating, and in vitro digestion. The results showed that the B-EVs had a desirable particle size (88.2 ± 7.7 nm). Protein and total RNA concentrations were 582 ± 11.2 μg/mL and 15.4 μg/mL, respectively. The optimal storage temperatures for B-EVs were 4 °C and -80 °C for short- and long-term storage, respectively. Fluorescent labeling and qRT-PCR tests showed that B-EVs could be specifically internalized by Caco-2 cells, whereas virtually no cytotoxic or growth-inhibitory effects were observed. B-EVs down-regulated the expression levels of IL-1β and IL-8 and up-regulated the expression levels of NF-κβ and TLR5 in Caco-2 cells. Overall, the results proved that the intact structure of B-EVs could be preserved during food storage and processing conditions. B-EVs had the ability to reach the human intestine through oral delivery. Moreover, they could be absorbed by intestinal cells and affect human intestinal function.

Unraveling the Phase Behavior, Mechanical Stability, and Protein Reconstitution Properties of Polymer-Lipid Hybrid Vesicles.

Hybrid vesicles consisting of natural phospholipids and synthetic amphiphilic copolymers have shown remarkable material properties and potential for biotechnology, combining the robustness of polymers with the biocompatibility of phospholipid membranes. To predict and optimize the mixing behavior of lipids and copolymers, as well as understand the interaction between the hybrid membrane and macromolecules like membrane proteins, a comprehensive understanding at the molecular level is essential. This can be achieved by a combination of molecular dynamics simulations and experiments. Here, simulations of POPC and PBD22-b-PEO14 hybrid membranes are shown, uncovering different copolymer configurations depending on the polymer-to-lipid ratio. High polymer concentrations created thicker membranes with an extended polymer conformation, while high lipid content led to the collapse of the polymer chain. High concentrations of polymer were further correlated with a decreased area compression modulus and altered lateral pressure profiles, hypothesized to result in the experimentally observed improvement in membrane protein reconstitution and resistance toward destabilization by detergents. Finally, simulations of a WALP peptide embedded in the bilayer showed that only membranes with up to 50% polymer content favored a transmembrane configuration. These simulations correlate with previous and new experimental results and provide a deeper understanding of the properties of lipid-copolymer hybrid membranes.

Influence of N-Glycosylation on Virus-Host Interactions in Halorubrum lacusprofundi.

N-glycosylation is a post-translational modification of proteins that occurs across all three domains of life. In Archaea, N-glycosylation is crucial for cell stability and motility, but importantly also has significant implications for virus-host interactions. While some archaeal viruses present glycosylated proteins or interact with glycosylated host proteins, the direct influence of N-glycosylation on archaeal virus-host interactions remains to be elucidated. In this study, we generated an N-glycosylation-deficient mutant of Halorubrum lacusprofundi, a halophilic archaeon commonly used to study cold adaptation, and examined the impact of compromised N-glycosylation on the infection dynamics of two very diverse viruses. While compromised N-glycosylation had no influence on the life cycle of the head-tailed virus HRTV-DL1, we observed a significant effect on membrane-containing virus HFPV-1. Both intracellular genome numbers and extracellular virus particle numbers of HFPV-1 were increased in the mutant strain, which we attribute to instability of the surface-layer which builds the protein envelope of the cell. When testing the impact of compromised N-glycosylation on the life cycle of plasmid vesicles, specialized membrane vesicles that transfer a plasmid between host cells, we determined that plasmid vesicle stability is strongly dependent on the host glycosylation machinery. Our study thus provides important insight into the role of N-glycosylation in virus-host interactions in Archaea, while pointing to how this influence strongly differs amongst various viruses and virus-like elements.

Morphogenesis of starfish polymersomes

The enhanced membrane stability and chemical versatility of polymeric vesicles have made them promising tools in micro/nanoreactors, drug delivery, cell mimicking, etc. However, shape control over polymersomes remains a challenge and has restricted their full potential. Here we show that local curvature formation on the polymeric membrane can be controlled by applying poly(N-isopropylacrylamide) as a responsive hydrophobic unit, while adding salt ions to modulate the properties of poly(N-isopropylacrylamide) and its interaction with the polymeric membrane. Polymersomes with multiple arms are fabricated, and the number of arms could be tuned by salt concentration. Furthermore, the salt ions are shown to have a thermodynamic effect on the insertion of poly(N-isopropylacrylamide) into the polymeric membrane. This controlled shape transformation can provide evidence for studying the role of salt ions in curvature formation on polymeric membranes and biomembranes. Moreover, potential stimuli-responsive non-spherical polymersomes can be good candidates for various applications, especially in nanomedicine.