Dynamics of vesicle formation from lipid droplets: mechanism and controllability

Curcumin Transferosome-Loaded Thermosensitive Intranasal in situ Gel as Prospective Antiviral Therapy for SARS-Cov-2

Purpose

Immunomodulatory and broad-spectrum antiviral activities have motivated the evaluation of curcumin for Coronavirus infection 2019 (COVID-19) management. Inadequate bioavailability is the main impediment to the therapeutic effects of oral Cur. This study aimed to develop an optimal curcumin transferosome-loaded thermosensitive in situ gel to improve its delivery to the lungs.

Methods

Transferosomes were developed by using 33 screening layouts. The phospholipid concentration as well as the concentration and type of surfactant were considered independent variables. The entrapment efficiency (EE%), size, surface charge, and polydispersity index (PDI) were regarded as dependent factors. A cold technique was employed to develop thermosensitive in-situ gels. Optimized transferosomes were loaded onto the selected gels. The produced gel was assessed based on shape attributes, ex vivo permeability enhancement, and the safety of the nasal mucosa. The in vitro cytotoxicity, antiviral cytopathic effect, and plaque assay (CV/CPE/Plaque activity), and in vivo performance were evaluated after intranasal administration in experimental rabbits.

Results

The optimized preparation displayed a particle size of 664.3 ± 69.3 nm, EE% of 82.8 ± 0.02%, ZP of -11.23 ± 2.5 mV, and PDI of 0.6 ± 0.03. The in vitro curcumin release from the optimized transferosomal gel was markedly improved compared with that of the free drug-loaded gel. An ex vivo permeation study revealed a significant improvement (2.58-fold) in drug permeability across nasal tissues of sheep. Histopathological screening confirmed the safety of these preparations. This formulation showed high antiviral activity against SARS-CoV-2 at reduced concentrations. High relative bioavailability (226.45%) was attained after the formula intranasally administered to rabbits compared to the free drug in-situ gel. The curcumin transferosome gel displayed a relatively high lung accumulation after intranasal administration.

Conclusion

This study provides a promising formulation for the antiviral treatment of COVID-19 patients, which can be evaluated further in preclinical and clinical studies.

Preparation, characterization, and Co-delivery of cisplatin and doxorubicin-loaded liposomes to enhance anticancer Activities

Ovarian cancer stands as a leading cause of cancer-related deaths among women globally. This malignancy has hindered successful treatment attempts due to its inherent resistance to chemotherapy agents. The utilization of cisplatin and doxorubicin-loaded liposomes emerges as a strategically advantageous approach in the realm of biomedical applications. This strategy holds promise for augmenting drug efficacy, mitigating toxicity, refining pharmacokinetics, and facilitating versatile drug delivery while accommodating combination therapies. In pursuit of scholarly investigations, the eminent databases, including PubMed/MEDLINE, ScienceDirect, Scopus, and Google Scholar, were meticulously scrutinized. Within this study, a nano-liposomal formulation was meticulously designed to serve as a co-delivery system. This system was optimized by varying lipid concentrations, hydration time, and DSPC: cholesterol molar ratios to efficiently encapsulate and load doxorubicin (DOX) and cisplatin (CIS) to overcome drug resistance problems. The Lipo (CIS + DOX) formulation underwent rigorous characterization including dimensions, entrapment efficiencies and drug release kinetics. Notably, the entrapment efficiency of cisplatin and doxorubicin loaded liposomal nanoparticles was an impressive 85.29 ± 1.45 % and 73.62 ± 1.70 %, respectively. Furthermore, Lipo (CIS + DOX) drug release kinetics exhibited pH-dependent properties, with lower drug release rates at physiological pH (7.4) than acidic (pH 5.4). Subsequent cytotoxicity assays revealed the enhanced biocompatibility of dual-drug liposomes with HFF cells compared to free drug combinations. Impressively, CIS and DOX-loaded liposomes induced significant cytotoxicity against A2780 in comparison to free drugs and combinatorial free drugs. Furthermore, the CIS and DOX-loaded liposome showed induced apoptotic potential and cell cycle arrest in A2780 compared to CIS, DOX, and their combination (CIS + DOX). Combining CIS and DOX via liposomal nanoparticles introduces a promising therapeutic avenue for addressing ovarian cancer. These nano-scale carriers hold the potential for attenuating the untoward effects of singular drugs and their attendant toxicities.

Formulation optimization, in vitro and in vivo evaluation of niosomal nanocarriers for enhanced topical delivery of cetirizine

Cetirizine hydrochloride (CTZ), a second-generation anti-histaminic drug, has been recently explored for its effectiveness in the treatment of alopecia. Niosomes are surfactant-based nanovesicular systems that have promising applications in both topical and transdermal drug delivery. The aim of this study was to design topical CTZ niosomes for management of alopecia. Thin film hydration technique was implemented for the fabrication of CTZ niosomes. The niosomes were examined for vesicle size, surface charge, and entrapment efficiency. The optimized niosomal formulation was incorporated into a hydrogel base (HPMC) and explored for physical characteristics, ex vivo permeation, and in vivo dermato-kinetic study. The optimized CTZ-loaded niosomal formulation showed an average size of 403.4 ± 15.6 nm, zeta potential of - 12.9 ± 1.7 mV, and entrapment efficiency percentage of 52.8 ± 1.9%. Compared to plain drug solution, entrapment of CTZ within niosomes significantly prolonged in vitro drug release up to 12 h. Most importantly, ex-vivo skin deposition studies and in vivo dermato-kinetic studies verified superior skin deposition/retention of CTZ from CTZ-loaded niosomal gels, compared to plain CTZ gel. CTZ-loaded niosomal gel permitted higher drug deposition percentage (19.2 ± 1.9%) and skin retention (AUC0-10h 1124.5 ± 87.9 μg/mL.h) of CTZ, compared to 7.52 ± 0.7% and 646.2 ± 44.6 μg/mL.h for plain CTZ gel, respectively. Collectively, niosomes might represent a promising carrier for the cutaneous delivery of cetirizine for the topical management of alopecia.

Telmisartan-Loaded Lactosylated Chitosan Nanoparticles as a Liver Specific Delivery System: Synthesis, Optimization and Targeting Efficiency

Hepatocellular carcinoma (HCC) has a significant economic impact and a high mortality rate. Telmisartan (TLM) is a potential therapy for HCC, but it has a limited scope in drug delivery due to unpredictable distribution and poor bioavailability. The objective of this study was to prepare, design, and in vitro evaluate lactose-modified chitosan nanoparticles (LCH NPs) as a liver-targeted nanocarrier for TLM with the potential to offer a promising HCC therapy. The combination of chitosan with lactose was successfully attained using the Maillard reaction. TLM-LCH NPs were prepared, characterized, and optimized with the developed 2³ full factorial design. The optimized formulation (F1) was in vitro and in vivo characterized. LCH was synthesized with an acceptable yield of 43.8 ± 0.56%, a lactosylation degree of 14.34%, and a significantly higher aqueous solubility (6.28 ± 0.21 g/L) compared to native chitosan (0.25 ± 0.03 g/L). In vitro characterization demonstrated that, F1 had a particle size of 145.46 ± 0.7 nm, an entrapment efficiency of 90.21 ± 0.28%, and a surface charge of + 27.13 ± 0.21 mV. In vitro TLM release from F1 was most consistent with the Higuchi model and demonstrated significantly higher release at pH 5.5. Moreover, a significantly higher ratio of liver to plasma concentration was observed with TLM-LCH NPs compared to plain TLM and unmodified TLM-NPs. The obtained results nominate TLM-LCH NPs as a promising carrier for enhancing liver targeting of TLM in treatment of HCC.

Asymmetric Lipid Vesicles: Techniques, Applications, and Future Perspectives as an Innovative Drug Delivery System

Novel lipid-based nanosystems have been of interest in improving conventional drug release methods. Liposomes are the most studied nanostructures, consisting of lipid bilayers ideal for drug delivery, thanks to their resemblance to the cell plasma membrane. Asymmetric liposomes are vesicles with different lipids in their inner and outer layers; because of this, they can be configured to be compatible with the therapeutic drug while achieving biocompatibility and stability. Throughout this review, topics such as the applications, advantages, and synthesis techniques of asymmetric liposomes will be discussed. Further, an in silico analysis by computational tools will be examined as a helpful tool for designing and understanding asymmetric liposome mechanisms in pharmaceutical applications. The dual-engineered design of asymmetric liposomes makes them an ideal alternative for transdermal drug delivery because of the improved protection of pharmaceuticals without lowering adsorption rates and system biocompatibility.

Use of Novasomes as a Vesicular Carrier for Improving the Topical Delivery of Terconazole: In Vitro Characterization, In Vivo Assessment and Exploratory Clinical Experimentation

Purpose

This manuscript aimed at encapsulating an antifungal terconazole (TCZ) into innovative novasomes for improving its penetration into the skin and clinically modulating its therapeutic efficacy.

Methods

Novasomes containing free fatty acid (FFA) as a penetration enhancer were formulated using ethanol injection technique based on 2⁴ full factorial design to explore the impact of various formulation variables on novasomes characteristics regarding entrapment efficiency percent (EE%), particle size (PS), polydispersity index (PDI), and zeta potential (ZP). The optimum formulation was chosen using Design-Expert^® software and utilized for further explorations.

Results

The chosen formulation (N15; including 100 mg lipid components and Span 80 to oleic acid in a ratio of 2:1 (w/w)) exhibited an EE% = 99.45 ± 0.78%, PS = 623.00 ± 2.97 nm, PDI = 0.40 ± 0.04, and ZP = −73.85 ± 0.64 mV. N15 showed spherical vesicles with a higher deformability index (DI) (9.62 ± 0.15 g) compared to traditional niosomal formulation (0.92 ± 0.12 g). Further, N15 showed superior inhibition of Candida albicans growth relative to TCZ suspension using XTT (2,3-bis-(2-methyloxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) reduction assay. Moreover, in vivo skin deposition tests revealed a superior TCZ deposition inside the skin from N15 in comparison to traditional niosomal formulation and TCZ suspension. Furthermore, histopathological examination for rats assured the safety of N15 for topical use. A clinical study conducted on infants suffering from napkin candidiasis proved the superiority of N15 to placebo in providing a complete cure of such fungal infections.

Conclusion

Concisely, the obtained outcomes confirmed the pronounced efficacy of N15 to successfully treat skin fungal infections.

Self-Assembly Behavior of Amphiphilic Janus Dendrimers in Water: A Combined Experimental and Coarse-Grained Molecular Dynamics Simulation Approach

Amphiphilic Janus dendrimers (JDs) are repetitively branched molecules with hydrophilic and hydrophobic components that self-assemble in water to form a variety of morphologies, including vesicles analogous to liposomes with potential pharmaceutical and medical application. To date, the self-assembly of JDs has not been fully investigated thus it is important to gain insight into its mechanism and dependence on JDs’ molecular structure. In this study, the aggregation behavior in water of a second-generation bis-MPA JD was evaluated using experimental and computational methods. Dispersions of JDs in water were carried out using the thin-film hydration and ethanol injection methods. Resulting assemblies were characterized by dynamic light scattering, confocal microscopy, and atomic force microscopy. Furthermore, a coarse-grained molecular dynamics (CG-MD) simulation was performed to study the mechanism of JDs aggregation. The obtaining of assemblies in water with no interdigitated bilayers was confirmed by the experimental characterization and CG-MD simulation. Assemblies with dendrimersome characteristics were obtained using the ethanol injection method. The results of this study establish a relationship between the molecular structure of the JD and the properties of its aggregates in water. Thus, our findings could be relevant for the design of novel JDs with tailored assemblies suitable for drug delivery systems.

The Peroxygenase Activity of the Aspergillus flavus Caleosin, AfPXG, Modulates the Biosynthesis of Aflatoxins and Their Trafficking and Extracellular Secretion via Lipid Droplets

Aflatoxins (AF) are highly detrimental to human and animal health. We recently demonstrated that the Aspergillus flavus caleosin, AfPXG, had peroxygenase activity and mediated fungal development and AF accumulation. We now report the characterization of an AfPXG-deficient line using reference strain NRRL3357. The resulting fungal phenotype included a severe decrease in mycelium growth, failure to sporulate, and reduced AF production. Increasing cellular oxidative status by administration of hydrogen peroxide and cumene hydroperoxide did not restore the AfPXG-deficient phenotype, which suggests that AfPXG-deficiency is not directly related to oxidative stress. To investigate possible alternative roles of AfPXG, a gain of function approach was used to overexpress AfPXG, with the reporter gene Gfp, in an AfPXG-deficient line, termed AfPXG+ . The resulting phenotype included elevated numbers of stable lipid droplets (LDs) plus enhanced AF production. Highly purified LDs from AfPXG+ cultures sequestered AF and this ability was positively correlated with overall LD number. Site-specific mutagenesis of AfPXG to delete Histidine 85 (AfPXGHis85), a residue essential for its catalytic activity, or deletion of the putative LD targeting domain (AfPXGD126-140), showed that AfPXG-peroxygenase activity was required for AF biosynthesis and that integration of AF into LDs was required for their export via a LD-dependent pathway. Ectopic expression in fungal cells of the plant LD-associated protein, oleosin, also resulted in both additional LD accumulation and enhanced AF secretion. These results suggest that both fungal LDs and their associated caleosin proteins are intimately involved in the biosynthesis, trafficking, and secretion of AF.

Ballistic Penetration of Highly Charged Nanoaerosol Particles through a Lipid Monolayer

To be used as a drug, inhaled nanoaerosol particles (NAPs) must first penetrate the lipid layer on top of the lung fluid before they will be able to reach the lung epithelium. We investigated how the penetration of NAPs through a model lipid monolayer (LM) depends upon their charging level and size. It was shown that deposition of NAPs 20-200 nm in diameter and charged to the Rayleigh limit gradually increased the surface tension of a dipalmitoylphosphatidylcholine monolayer (DPPC), indicating a loss of lipid molecules from the monolayer. This phenomenon was reproduced with a variety of NAPs produced from glucose, proteins, and polymers. Transfer of the lipid material into the subphase was documented by direct visualization of lipid nanoparticles in the subphase with atomic force microscopy after deposition of glucose NAPs on a DPPC monolayer, followed by collection of the lipid nanoparticles on a mica surface. Partial restoration of tension upon storage indicates that some of the lipid may return to the monolayer. Experiments with the deposition of highly charged calibrated polystyrene nanoparticles showed that the amount of lipid removed from the surface was roughly proportional to the overall surface area of the deposited NAPs. When the number of charges on the NAPs was reduced from their Rayleigh level of 10³-10⁴ units to 1-10 units, no notable changes in monolayer surface tension were observed even with prolonged deposition of such NAPs. It was therefore concluded that only highly charged NAPs of a certain size acquire sufficient speed from their attraction by mirror charges to enable ballistic penetration through a lipid monolayer.

Force Field Development for Lipid Membrane Simulations

With the rapid development of computer power and wide availability of modelling software computer simulations of realistic models of lipid membranes, including their interactions with various molecular species, polypeptides and membrane proteins have become feasible for many research groups. The crucial issue of the reliability of such simulations is the quality of the force field, and many efforts, especially in the latest several years, have been devoted to parametrization and optimization of the force fields for biomembrane modelling. In this review, we give account of the recent development in this area, covering different classes of force fields, principles of the force field parametrization, comparison of the force fields, and their experimental validation. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.

Lipid nanotechnology

Nanotechnology is a multidisciplinary field that covers a vast and diverse array of devices and machines derived from engineering, physics, materials science, chemistry and biology. These devices have found applications in biomedical sciences, such as targeted drug delivery, bio-imaging, sensing and diagnosis of pathologies at early stages. In these applications, nano-devices typically interface with the plasma membrane of cells. On the other hand, naturally occurring nanostructures in biology have been a source of inspiration for new nanotechnological designs and hybrid nanostructures made of biological and non-biological, organic and inorganic building blocks. Lipids, with their amphiphilicity, diversity of head and tail chemistry, and antifouling properties that block nonspecific binding to lipid-coated surfaces, provide a powerful toolbox for nanotechnology. This review discusses the progress in the emerging field of lipid nanotechnology.

On protein crowding and bilayer bulging in spontaneous vesicle formation

Spontaneous aggregation of lipids into bilayers and vesicles is a key property for the formation of biological membranes. Understanding the compartmentalization achieved by vesicle formation is an important step toward understanding the origin of life, and is crucial in current efforts to develop artificial life. Spontaneously formed vesicles may be applied as artificial cells if they can efficiently encapsulate biomacromolecules. Recent studies report an enhanced concentration of encapsulated proteins during vesicle formation. In order to obtain more insight into this encapsulation process, here we simulate the spontaneous transition of flat bilayers to vesicles in the presence of solvated model proteins using molecular dynamics simulations. In the bilayer-vesicle transition, which is found to be unaffected by the presence of the solvated proteins, the bilayer edge remains at almost the same height, while the center of the membrane bulges out, a molecular pathway we denominate "bilayer bulging". This bulging results in an interior protein concentration that is significantly lower than that of the solution. By means of an increased protein-membrane interaction, enhanced encapsulation of proteins inside the vesicles could be achieved in our simulations.

Structure of ABCA tetrablock copolymer vesicles and their formation in selective solvents: a Monte Carlo study

Vesicles formed by ABCA tetrablock copolymers in solvents that are selective for block A are studied using the Monte Carlo simulation. Simulation results show that the chain length ratio and hydrophobicity of blocks B and C are key factors determining the hydrophobic layer structure of the vesicles. If the B and C blocks are of the same hydrophobicity, the longer block C tends to form the closed hydrophobic layer, whereas the shorter block B is located on the outer surface of the closed hydrophobic layer. However, if the hydrophobicity difference between blocks B and C is high enough, the reverse will occur given that block B has a higher hydrophobicity and block C has a lower hydrophobicity. The kinetics of vesicle formation is also studied. Simulation results reveal that the hydrophobic layer structure is formed through the migration of the polymer chain within the vesicle membrane after the formation of the vesicle profile. This migration is independent of the differences in chain length ratio and the hydrophobicity between the blocks B and C. The packing mode and the migration of polymer chains within the vesicle membrane are also presented and discussed.

Modeling the self-assembly of lipids and nanotubes in solution: forming vesicles and bicelles with transmembrane nanotube channels

Via dissipative particle dynamics (DPD), we simulate the self-assembly of end-functionalized, amphiphilic nanotubes and lipids in a hydrophilic solvent. Each nanotube encompasses a hydrophobic stalk and two hydrophilic ends, which are functionalized with end-tethered chains. With a relatively low number of the nanotubes in solution, the components self-assemble into stable lipid-nanotube vesicles. As the number of nanotubes is increased, the system exhibits a vesicle-to-bicelle transition, resulting in stable hybrid bicelle. Moreover, our results reveal that the nanotubes cluster into distinct tripod-like structures within the vesicles and aggregate into a ring-like assembly within the bicelles. For both the vesicles and bicelles, the nanotubes assume trans-membrane orientations, with the tethered hairs extending into the surrounding solution or the encapsulated fluid. Thus, the hairs provide a means of regulating the transport of species through the self-assembled structures. Our findings provide guidelines for creating nanotube clusters with distinctive morphologies that might be difficult to achieve through more conventional means. The results also yield design rules for creating synthetic cell-like objects or microreactors that can exhibit biomimetic functionality.